ST EREO - americanradiohistory.com · 2019-07-17 · form of projection unit. Acoustic boundaries...

ST EREO1 9 6 1 TECHNICAL ARTICLES

Stereo Cartridges Discs Styli Arms

Changers & Players Speaker Systems

Tape Recorders Selling Stereo

Stereo Packages Stereocasting

Equipment Selection

BUYERS DIRECTORY OFMANUFACTURERS & PRODUCTS

Names Addresses Products

Models Prices

Published by ELECTRONIC TECHNICIAN Magazine

From 18 to 40,000 cps

. ~W. ., ó .,,;,

TA260 Festival II -60 Watt Stereo AM -FM ReceiverThe most powerful receiver of all-the new Stereo Festi-val II, model TA260, delivers 60 undistorted watts from18 to 40,000 cycles. But the actual performance of theFestival goes beyond the point of superb specifications.It is the best sounding stereophonic receiver you can buy.

The "Citation Sound," acclaimed by audio authoritieseverywhere, was developed by Harman-Kardon in thedesign of its remarkable new Citation instruments. It isprecisely this quality that distinguishes the performanceof the new TA260: the clean, solid bass; the silky trans-parent highs. And, there is power - power to spare, todrive the most inefficient speakers. The result: the newStereo Festival II actually sounds recognizably best -regardless of price.

Music Power Output in accordance with IHFM standards, 1,4% distortion.

The TA260 includes a powerful 60 watt stereo amplifier (120 wattpeaks ), separate and remarkably sensitive AM and FM sectionsand dual preamplifiers with all the controls necessary to achievethe finest performance from all program sources.Features: SPECIALLY DESIGNED MASSIVE OUTPUT TRANSFORMERSinsure superior bass and high frequency response; HEAVY DUTYOUTPUT TUBES, conservatively rated, provide high power outputwith far less heat and longer life; DUAL FRICTION -CLUTCH TONECONTROLS; BLEND CONTROL to eliminate "hole -in -the -middle" effect;SPEAKER PHASING; two MAGNETIC INPUTS; SPECIAL HEADPHONE RE-CEPTACLE; CLOSE TRACKING LOUDNESS CONTROL; CONTOUR, RUMBLEand SCRATCH FILTERS; separate BAR -TYPE TUNING EYES for AM andFM; THIRD CHANNEL AMPLIFIER OUTPUT. The Stereo Festival IIis handsomely designed in brushed gold and charcoal brown.The Stereo Festival II, Model TA260... $299.95. CX26 MetalEnclosure... $12.95. WW30A Walnut Enclosure... $29.95.For more complete information on the Stereo Festival II, write:Dept. ET -61, Harman-Kardon, Westbury, N. Y.

All prices slightly higher in the West.

harman kardonFor more data, circle 9-80-1 on coupon, p. 78

80 ELECTRONIC TECHNICIAN September, 1960

TEBEO 1961CONTENTS

FEATURES and ARTICLES

Adjusting Stereo To The Room Environment 85

Solving The Stereo Disc Puzzle .... 88

The Stereo Cartridge Stylus Partnership 90

Loudspeaker Installation Problems 92

Status Of Stereo Broadcasting 98

Stereo Changers, Players And Turntables 102

Analyzing Stereo Tape Equipment 104

Evaluating Stereo Packages 106

Stereo Sales Set -Up For Dealers 108

Audio Newsletter 113

New Products 117

BUYERS DIRECTORY

Products listed under each manufacturerCompany names

A to D 111 L to S 114

D to L 112 S to T 115

T to W 116

ALBERT J. FORMAN ARTHUR P. SALSBERGEditor Managing Editor

NORMAN CROWHURST B. V. SPINETTA CHARLES DREYERStereo Consultant Directory Editor Art Director

STEREO 1961 is published by ELECTRONIC TECHNICIANMagazine, the leading technical journal of the audio -electronic maintenance field. Printed in U.S.A. 50C per copy.

Copyright 1960 by Electronic Technician, Inc.,480 Lexington Avenue, New York 17, N.Y.

HOWARD A. REED, Publisher

Another Philco first!

Philco

MODEL 1720R READY NOWT Besides REVERB has a five -speaker stereo sound andamplifier system. Two speakers with matching grille cloth play inside-or outside-forup to 30 ft. of separation! Lightweight tone arm and dual sapphire needle. 45 -RPMspindle and tape input jack. Provision for drop -in, play -in AM-FM tuner. Mahogany-,walnut- or maple -finish cabinets.

MAGAZINE ADS

' Pa.ce Muncel

DISPLAVS ,. PHILCO_ REVERRaphonkSound

/

EXCLUSIVE PHILCO ADVERTISING CAMPAIGNOnly Philco gives you the drawingpower of famous PATRICE MUNSELto pull customers into your store!

DEALER ADSBANNERS

Complete national and local ad campaign! In leading national magazines- local newspapers - even musical mailers - Patrice Munsel will invitecustomers into your store for a Philco REVERBaphonic Sound Systemdemonstration! And when they come in, there's Miss Munsel in yourwindow - on your sales floor - in life-size, lifelike full color! Get in onthis nationwide Philco REVERB promotion! It's ready now!Call your Philco Distributor today! Don't miss seeing and hearing PhilcoREVERB at your Distributor's.

TIE IN! BUY IN! AND YOU'LL SELL RIGHT NOW!82

ELECTRONIC TECHNICIAN September, 1960

Ready now for immediate delivery!The newest, most exciting sound in music!

REVERS!The new dimension in sound... the step beyond stereo!Another Philco exclusive...Patrice Munsel is ready to help you sell thePhilco REVERBaphonic Sound System now!The new Philco REVERBaphonic Sound System makes any record-monaural,stereo-even old 78's-sound thrillingly different-alive!-new! No new records

to buy! New Philco REVERBaphonic Sound System transforms AM/FM andtape! Exclusive REVERB Demonstrator lets you show customers the livingdifference right on your sales floor. Turn on REVERB and the walls seem to

roll back. Customers will literally leap with amazement! It's the most dem-

onstrable feature in phonograph history! And you can deliver Philco REVERB

right now! No waiting, no delay!AND THAT'S NOT ALL!

Philco backs REVERB with an all-out national and local TV, magazine and

newspaper promotion! Tied right to your store! See details on opposite page.

MOST EXCITING "DEMO" EVERT No more fuss-ing with acoustical backdrops, no more specialfloor arrangements. With this remote controlit's "push-button" easy to demonstrate PhilcoREVERS anywhere in your store. It's analmost unbelievable musical experience!

. .. /,.

"4,11,111111._.ti..:.,

TURNS YOUR STORE AND YOUR CUSTOM-ER'S ROOM INTO A VAST CONCERT HALL!Philco REVERB rolls back the walls! Even asmall room becomes a ballroom with REVERB.Your customers have never heard anythinglike it. They must hear it to believe it!

FOR THE MOST ADVANCEDFEATURES IN HIGH FIDELITY

YOU NEED

EMI

CONTROL PANEL HAS EXCLUSIVE REVERBDIAL WITH 4 DEGREE SETTINGS! Custom -blend your own REVERS. It's so easy! Uniquecontrol knob lets you add as much or as littleREVERB as you want. There's absolutelynothing like it! And it's ready now!

C flOP CITDD®For more data, circle 9-83-1 on coupon, p. 78

ELECTRONIC TECHNICIAN September, 1960 83

MOST SENSITIVE!

MOST POWERFUL!

The New 6o-Watt

FISHER 800Stereo Receiver

THE NEW FISHER 800 is twice as sensitive as any other receiver in the over $400 price range-and the mostpowerful! THE STEREO AMPLIFIER features the new, revolutionary Type -7591 power output tube,

producing 60 watts of Music Power totally devoid of audible hum, noise and distortion! THE FM TUNERprovides 1 microvolt sensitivity for 20 db of quieting; with the identical GOLDEN CASCODE front-end builtinto the FISHER tuners used by broadcast stations! THE AM TUNER delivers a signal of FM calibre,free of hiss and birdies. THE STEREO MASTER AUDIO CONTROL has 22 controls, including anexclusive, front -panel Center Channel Volume Control! Before you buy any stereo receiver, protect yourinvestment-remove the bottom cover from the 800 and any other stereo receiver. Compare the immaculatewiring assembly of the 800 to the others. The difference will amaze you! No other receiver can w A50match the quality, the finger-tip simplicity and grand -organ flexibility of the FISHER 800. $4295°J

WRITE TOD4V FOR DETAILED BROCHURE ON THE FISHER 800!

FISHER RADIO CORPORATION 21-24 44TH DRIVE L. I. CITY 1, N.Y.For more data, circle 9-84-1 on coupon, p. 78


Adjusting Stereo To The RoomEnvironment

Selection, Placement & Adjustment Of Equipment To Suit Room

Acoustics For Optimum Listening A stereo high fidelity show lastyear had as its theme, "DecorateYour Home With Music." It empha-sized selection of components tovisually suit a decor.

This theme is certainly not anobjectionable one, since visual ac-ceptance brings stereo greater salesacceptance.

What appears more important,however, in the final analysis, isacoustical satisfaction for thecustomer's ears. How a stereo sys-tem sounds in the home will deter-mine stereo's "staying power." Thismeans suiting the room decoracoustically.

As well as using different colorsand styles of furnishing to comple-ment a room, every room must be"adjusted" to complement its soundcharacteristics, too. It is not too farfetched to say that furnishingsmust be adjusted to the system forbest stereo results. Since the audioprofessional and technician is lim-ited in this direction, the next best

Fig. 1-Arrangement for a typical oblongroom with two doors at one end and picturewindow at the opposite end.

4-3PICTURE WIND^W

SEPARATEMID -RANGE

6 TWEETERSFOR EACH CHANNEL-,

SINGLEWOOFER

thing is to adjust the stereo equip-ment to the furnishings, for opti-mum results.

Acoustic Treatment

Most rooms can be improvedacoustically. If a customer has themoney to build and properly fur-nish a room specially for listeningto stereo, skillful use of acoustictile, drapes, etc., will help achievethe best overall sound effect. Butfew persons willingly go to this ex-pense. For most, the placement ofabsorption and reflecting surfacesis limited.

Consequently, a stereo systemmust be designed and built to suitthe room. Primarily, this meansproper selection and placement ofspeakers to provide an optimumlistening area. Some arrangementsare shown in Figs. 1 through 6 forvarious type rooms. Since there canbe an almost infinite variety ofroom conditions to satisfy-differ-ent sizes, shapes, varying areas of

Fig. 2-One arrangement for "L" shapedroom with each channel enclosure projecting90 apart. Note effective listening area.

r_\CHANNE.

2

STEREODUE TO

SECONDARYEFFECT

/ STEREODUE TO

SECONDARYA EFFECTNAIN

Pleasure

NO CORNERTHIS SIDE,

SUITABLE FORSPEAKER \

SINGLE SATELLITE SYSTEMCOMPLETES STEREO EFFECT

EXISTINGCORNER

SPEAKER

l/N/1

LISTENING

AREA

Fig. 3-Unorthodox room area uses singlesatellite with corner enclosure for complet-ing true stereo listening area.

reflecting and absorbing surfaceson walls, ceiling and floor-thesearrangements are to be consideredas helpful guides only.

As the professional audio manalready knows, a room, in effect, be-comes part of a speaker's enclosure.For this reason, rooms with bothdimensions less than 10 to 15 feetare best served generally by someform of projection unit. Acousticboundaries of the room are effec-tively expanded, and inconsisten-cies developed by a "big" speakersystem are avoided. (See Fig. 5A)

When both dimensions of a roomare more than 20 to 25 feet, projec-tion units are not desirable. Speak-ers should be well spaced, prefera-bly in corner enclosures (See Figs.4 and 5-B). Reverberant effects ofthe "big" system (similar to that ina movie theatre) will be acceptablein the large room, although somelisteners prefer some absorbingmaterial at the four wall centers toreduce reverberation time and im-prove intelligibility.

Depending upon a number of fac-tors, rooms of medium size may beeasier or more difficult to handle.Either system may be used but each


must be adapted specifically to suitthe acoustic properties of the par-ticular room.

Audio text books frequently ex-plain in detail how to set up stereoin a convenient rectangular (ob-long) room. But it is surprisinghow many rooms have some othershape, particularly some form ofL -shaping. (See Figs. 2 and 6A).Even when these rooms are oblong,

MID -RANGE MID -RANGESPEAKER SPEAKER

AREA OF" TRUE" STEREO

MID -RANGE FREQUENCIES CONTRIBUTE

MOST TO THE STEREO EFFECT IN THIS AREA

Fig. 4-Typical "average" room stereo ar-rangement with two corner enclosures.

varying wall surfaces require de-liberate out -of -balance treatment.Such an arrangement is shown inFig. 6B.

Careful consideration of theacoustic characteristics of a room'swalls, floor and ceiling height be-fore speakers are selected and lo-cated cannot be overstressed. Fur-thermore, at some point the cus-tomer should be advised that anover -stuffed wing or barrel backchair seldom makes a good listen-ing chair-even when located in thebest sound area. Absorbing mate-rial near the listener's ear is a high-ly undesirable condition.

Speaker Enclosure Selections

For this discussion, loudspeakerscan be placed in three groups, asfollows : Omnidirectional-givingsmooth radiation in all directions;directional - concentrating thesound into a fairly narrow beam;and semi-directional-usually re-stricting the sound to horizontaldirections, but distributing it wellaround in the horizontal plane.

When a room's floor and ceilingare absorbent, with carpet andacoustic tile, but with reflectivewalls (painted plaster or glass win-dows) diffuse omnidirectional

speakers will probably do the bestjob.

Where the walls are also absor-bent, with drapes, bookshelves,paintings, and other absorbent ma-terials present in wall center areas,omnidirectional speakers frequentlyseem over "dead." In this case, di-rectional units can be used to beamthe sound to null or "dead" points.

The typical "recreation room,"having bare composition tile floorsand ceiling, with painted or barewood walls, and metal -canvas -slingfurniture, can be helped some bytiling the ceiling. Semi -directionaltype speakers can also help by hori-zontal radiation, minimizing reflec-tions from floor and ceiling.

Separate speakers offer greaterplacement versatility. Conversely,speakers enclosed in one cabinet

Fig. 5 (A)-Two channel angle projection pro-vides optimum results for smaller room. (B)-Larger room gives better results with cornerenclosures. Absorbent surfaces are optional ineach case for reducing reverberation timeconstant.

ABSORBENTSURFACES

O SMALLER ROOM

ABSORBENT

SURFACES

................... . v..:::f:

LARGER ROOM

have less placement versatility.

Optimizing Equipment

Whether your customer has thenew dual units designed speciallyfor stereo, or two of the older mono-phonic type components, stereo isa more complicated installation.Because of this, many hi-fi listen-ers have become dissatisfied withstereo, concluding it doesn't work,or feel it is not worth it. Generally,the real cause of this dissatisfac-tion is that their system has notbeen optimized to perform as it canand should.

Frequency Balance

Audio professionals know aboutbalancing left and right-even if

Fig. 6 (A)-Another arrangement for an "L"shaped room. (B)-Arrangement for optimumresults where one wall is draped and the op-posite wall is reflecting.

411-DRAPES OR

ABSORBENCY

PLASTEROR GLASS

WINDOW


they disagree on the best way toachieve this. What is commonlyoverlooked is balance in the fre-quency range.

Some hi-fi owners have the habitof working their monophonic sys-tem with the maximum bass andtreble boost, under the impressionthis gives them a maximum of"everything." When they havestereo installed they continue thepractice-and are, more often thannot, disappointed with results.Some call their technician ; somegive up listening to stereo.

The customer should be advisedthat operating stereo in this man-ner leaves a hole in the response,right where it is important forgood stereo. The best setting iswith bass and treble controls bothclose to flat-neither boost nor roll -off.

System Phasing

For many reasons, a largeamount of confusion exists on thesubject of phasing. Some maintainthat phasing of stereo systemsmakes no noticeable difference.There may be some circumstanceswhere phasing makes little differ-ence, but it makes a very dramaticdifference, generally.

With one of the speaker systemsout -of -phase with the other, therewill be noticeable loss of bass, thin-ness or unnatural effect in the mid-range and treble, and confusion ofsound rather than a clear stereo ef-fect. The easiest way for the tech-nician to check this, if the preampdoes not have a phasing switch, isto reverse connections at one speak-er and see which is best, as shownin Fig. 7A.

But phasing must be checkedthroughout. It can be right onphono and wrong on tape. It may beeither way on radio, especially theAM/FM type. The system must bephased out so it is right on allmodes employed in the system.

An easy way to check phasing onphono is to play a mono record.This will show center location ofsound when correctly phased andbalanced. There is no such easyway to phase for tape and radio.

On phono or tape, phasing canbe switched at either the input oroutput. But on radio the only fea-sible place to change it is at the

loudspeaker (see Fig. 7A). Conse-quently, where radio is used, theloudspeakers must be phased tosuit radio, and the phono and tapeinput connections then used tophase these program sources, asshown in Fig. 7B.

Ground Loop Hum

When hum is a problem thestereo system should first bechecked for ground loops. Discon-

AM FMTUNER

DUALAMPLIFIERS

AO THESE LEADS CANNOT BEREVERSED BECAUSE ONESIDE OFEACH IS GROUND

TAPEHEAD

PHONOPICK-

UP

RADIO MUST BEPHASED AT THE SPEAKERS

DUALAMPLIFIERS

4 -TERMINAL TYPE PICKUP

Fig. 7 (A)-First step in proper phasing ofa stereo system should begin at voice coilsof speakers with radio reception. (B)-Tapeplayer or phono phasing is accomplished atthe tape head or phono pick-up.

nect everything except one mono-phonic channel from one input-say phono. If this clears the hum,it is probably ground loop trouble.If the hum appears only when thestylus touches the groove, it isn'thum at all and falls in the classifica-tion of rumble. The rumble may beeliminated by working on the mo-tor, but chances are a better turn-table or changer is needed.

Fig. 8-Ohmmeter is used to trace groundloop causing hum in stereo equipment.

Having proved it to be groundloop hum by removing everythingbut one channel and one input, nowconnect everything back, one at atime, until the culprit is located.Then trace the ground circuit tosee how the loop occurs. Ratherthan rely on a visual check, anohmmeter should be used to checkthe loop, as shown in Fig. 8. Thetrouble may not be a loop, as such,but a leaky power transformer al-lowing line currents to stray intothe ground system. Sometimes re-versing the power plug for the com-ponent causing trouble will mini-mize or eliminate the hum. The bestthing is a new transformer.

Remote Control

The nature of stereo motivatesthe listener's need and desire forremote control. It is difficult to ob-tain correct balance by walking overto the amplifier to make an adjust-ment and then go back to the chairto find out what results were ob-tained. But there are right andwrong ways to solve this problemby remote control from a favoritelistening point. Sometimes thewrong way can cause trouble : ei-ther a ground loop or loss of highsbecause of excessive cable capaci-tance.

There are two ways to avoid lossof highs caused by cable capaci-tance:

1. Reduce capacitance by em-ploying low capacitance cable.

2. Use a cathode follower at theinput to the remote cable.

A listener usually wants the pho-nograph, tuner and tape deck con-trols at the remote location, leavingonly the power amplifiers hiddenaway in the installation. For thiscombination, the preamp shouldhave a cathode follower output toprevent high frequency loss by thelong shielded leads to the ampli-fiers. If the customer's preamp doesnot have a cathode follower output,special low -capacitance cable mayprove satisfactory if the run is nottoo long.

Whether or not the hi-fi ownercalls because he is dissatisfied, thetechnician can boost his neighbor-hood prestige and customer's con-fidence by suggesting equipment op-timization. If not, the listener maybe disillusioned with stereo.


Fig. 1-The standard stereo recording andplay -back system is based on the Westrex45'/45 method of diagonal stylus movement.

The evolving art of stereo is firm-ly entrenched in the minds andpocketbooks of consumers. And, inthe disc -versus -tape controversy,stereo disc is the sales king, thusfar. Therefore, it is especially im-portant for technicians associatedwith audio sales and service to un-derstand the operating principlesof a stereo disc.

Solving The StereoDisc Puzzle

Theory And Practice Of Two Channels InOne Record Groove

45/45 System

Getting two channels into onegroove isn't as complex as it mightinitially appear. Record groovemodulations can be transmitted bya single stylus to a twin cartridgethrough diagonal movements, asshown in Fig. 1.

Let's consider the left channel

Fig. 2 (A)-When the left channel (inner wall of record groove) is modulated, the stylus movesdiagonally up to the right or down to the left. (B)-Stylus moves up to the left or down to theright when the right channel (outer groove wall) is modulated. Unmodulated grooves areshown as straight lines to simplify the drawing (they're actually curved).

LEFT HANDCHANNEL

UNMODULATED ORREFERENCE GROOVE

i REFERENCE i

y CENTER y 0

n".

4

OUTER SIDEWALL

GROOVE CENTER

INNER SIDEWALL

RIGHT HANDCHANNEL


REFERENCEv CENTER v

II

INNER SIDEWALL

GROOVE CENTER

OUTER SIDEWALL117

first, which is identified as the innerwall of the record groove, as seenby the viewer. Fig. 2A illustratesthe motion that the stylus will haveif only the left hand wall is mod-ulated : the stylus will travel some-where on an "up to the right" or"down to the left" plane, dependingon the inner sidewall's thickness.Fig. 2B illustrates the right handchannel with modulation. This isthe outer sidewall of the recordgroove. Accordingly, the stylus willtravel diagonally "up to the left"and "down to the right" if only thissidewall is modulated.

The stylus will travel up, eitherin the right 45° plane left45° plane, when the groove becomesnarrower. Or, conversely, it willtravel down when the groove be-comes wider. When the stylus movesback and forth, the center line ofthe modulated groove moves accord-ingly. The stylus tip, it should bepointed out, is always in the groovecenter and contacting both side-walls.

Although it is necessary to firstanalyze stereo recording principlesas a distinct right and left channel,it should be understood that bothchannels are recorded at the sametime; not right and left separately.In a similar manner, both channelsare played back at the same time.The stylus is in one position onlyat any given instant. This position"defines" both walls.

Vector Forces

Fig. 2 clearly illustrated how astylus can move diagonally by fol-lowing the groove modulations ofeither the left hand or right handchannel. A combination of bothforces, however, is more likely tooccur in a recording. The concept


The Stereo RecordHow does the stylus move when

Groove width changes? Groove center changes? Groove changes combine?

For answers to these, and otherperplexing stereo questions-see text.

of stereo sound, is, after all, a psy-cho -physical manifestation. Orches-tral instruments don't resoundfrom only the extreme left or right.Some instrument groups are placedat left center, some right center,some at the precise center, etc. Forsound direction to appear at otherthan extreme left or right, bothchannels must be modulated.

Fig. 3 illustrates how this occursin relation to stylus movement. Toreiterate, the stylus can only be inone position at a given instant. Theresultant force of the left channelforce and the right channel forceestablishes this position. When bothchannel walls push up at the sametime, with the same force, thestylus will travel straight up. Thisis only natural since both forces,which are opposite, yet equal, willneutralize each other.

When the grooves are narrow,the stylus is "pinched" and conse-quently raised vertically. As thegrooves widen, the stylus tip low-

ers vertically. This is shown in Fig.4. An out -of -phase force, that is,one channel pushing up while theother is cut beyond the referencepoint, resulting in a down force, willcause the stylus to travel laterally.The stylus' horizontal movementwill be to the left or right, depend-ing on the direction of the resultantforce. Fig. 3 illustrates a stylusmovement to the left due to the re-sultant force being in this direc-tion.

The stylus can, therefore, be dis-placed horizontally, vertically, orboth, from the reference point atany given instant.

Complex Grooves

Thus far, we have discussed leftand right sidewalls that are essen-tially the same, though having a90° relationship to each other. Buthow does the stylus operate whenboth channels are decidedly differ-ent? One mental conception thatmust be overcome to understandhow stereo grooves affect stylusmovement in relation to the draw-ings is : horizontal expansion andcontraction of the groove sidewallsindicate vertical movement. Thishorizontal motion is frequently mis-construed as stylus lateral motion.

The upper two drawings of Fig.4 illustrate this point. As the side -

Fig. 3-The instantaneous position of a stylus tracing a stereo record groove is determined by aforce which is the resultant of combining both left and right groove forces.

ONLY

CHANNEL AMODULATED

2

ONLY

CHANNEL BMODULATED

3

REFERENCE

BOTH

CHANNELS AaB

MODULATED

GROOVE

1111

5

4

\_2_/

3


Y 1

I,

INNERSIDEWALL

II 9

2G 5 31 6

OUTERSIDEWALL

6 3

3

OUTERSIDE

\WALL

GROOVE CENTER

Fig. 4-Pinched and expanded grooves makethe stylus rise or fall. A straight center lineindicates no lateral motion. Curved centerline shows lateral movement. Unvarying ref-erence groove width doesn't displace stylusvertically up or down.

walls widen and narrow the stylusis lowered or raised. It is only wherereference or groove center changesthat lateral stylus motion is de-scribed pictorially, as shown in thelower two drawings of Fig. 4.

The stylus can assume a positionthat is displaced both horizontallyand vertically from a given refer-ence point on a stereo recordgroove. The position will vary fromone instant to the next, dependingon the different width and lateraldisplacement of the groove at agiven instant.

Since the groove walls vary fromone instant to the next, they do notappear symmetrical, as indicatedin Fig. 5. The first stylus drawingshown displays lateral movementto the left and vertical motiondown. The stylus obviously tracedthe groove shown at its right. No-tice the displaced groove from thereference groove, indicating later -

(Continued on page 126)


The Stereo CartridgeStylus Partnership

Single -Stylus Twin -Channel Cartridges

Translate Stereo MechanicalForces Into Stereo Electrical Signals

CERAMICDR CRYSTAL

MOVING IRONor VARIABLE RELUCTANCE

MOVING MAGNET

Cartridge manufacturers madethe transition from monophoniccartridge to stereophonic cartridgeproduction in a remarkably shorttime (some mono cartridges arestill being produced for replace-ment purposes) . However, produc-tion is not the only important re-sult; improved quality and new de-sign concepts are major contribu-tions, also.

Piezo-electric cartridges arechallenging many magnetic car-tridges in today's stereo hi-fi mar-ket, whereas hi-fi aficionados for-merly held crystal or ceramiccartridges in low esteem. Thischanging attitude is due to manyimprovements, such as : lowertracking force, imperviousness tomoisture (for ceramics), and widerfrequency range. Other advantagesare : no hum pickup, self -equaliza-tion.

Since stereo hi-fi amplifiers donot always include a ceramic input,some piezo cartridge manufactur-ers include magnetic adapters,thereby allowing persons who pre-fer ceramics to use them in theirsystems. In spite of the inroadsmade by piezo cartridges, theirmajor use is still in package stereo,where preamplifiers and equaliza-tion is rarely employed.

Magnetic cartridges have notbeen stagnant, either. A new mag-netic design has made many friends-the moving magnet cartridge.Here, a magnet attached to a stylusmoves between stationary magneticcoils. Other magnetic cartridgeswere upgraded in performance.Moving iron and moving coil car -

Stereo Cartridge/Styli

Magnetic

Moving IronMoving CoilMoving Magnet

Piezo

CrystalCeramic

Styli Size

0.5 & 0.7 Mil

tridges are still very popular trans-ducers.

Operation

Cartridge design changes in-voked by stereo discs are essential-ly internal; externally, only thenumber of connection terminals,either three or four, identifies it as"stereo." Instead of a side -to -sidestylus motion transmitting me -

CHART I

Piezo Type Cartridges

Model

Recom-mended

LoadResistor

Recom-mendedTra cking

Force(Grams)

Astatic 2 meg 5-713TBX

CBS Electronics adapters 1 .5 4

Professional 55

CBSSC -1 1.2 meg 5-7SC -7 3 meg 5-7

Duotone 2 meg 2-4GPS 73

Electro -Voice 22K -47K 2-431 MD (for mag.input)

Erie 3 meg 4-6

Ronette .5 meg 4-6106

Sonotone 1-5 meg 3-68T

Weathers 47K 1-2C-501 3-6

* Higher force for record changers. Where twoforces are indicated, the higher range is for chang-ers; lower range for professional -type tone arms.


Fig. 1-Equal in -phase mechanical forces re-sult in moving the stylus vertically up ordown. Equal out -of -phase forces cause later-al left or right stylus movement.

CHART II

Magnetic Type Cartridges

Model

Recom-mended

LoadResisto-

Recom-mended"Tracking

Force(Grams)

Audio Empire 47K 2 5

88

Audio gersh 37K 4-6Stereotwin

Dynaco 47K 2-4Stereodyne

Electrosonic 47K 2 4

C-100

General Electric 100K 3.5 7GC -7

General Electric 47K 2 4

VR-225 5 -7VR-227

Grado 5K 3

Master

Norelco 68K 3-5AG 3400

Pickering 47K 2-7371

Pickering 47K 2-5380

Recoton 68K 3-5RG-745

Scott -London 50K 3-51000 (integrated arm)

Shure 47K 3-4M3D

Shure 47K 4-7M7DM8D

Shure 47K 1.5-2M216

(integrated arm)

* Higher force for record changers. Where twoforces are indicated, the higher range is for chang-ers; lower range for professional -type tone arms.

ELECTRICAL PHASEOUT

IN OUTMECHANICAL PHASE

SIGNALVOLTAGE

POLARITY

STYLUSMOTION

Fig. 2-Stereo recording standards require that in -phase signals result in lateral groove modu-lation. Mechanical in -phase forces, however, result in vertical displacement, as shown in Fig.

1. To comply with standards, one of the two cutter head coils are reversed. This reversal placesthe essentially in -phase bass signal modulations in the horizontal component of the disc, there-

fore minimizing vertical modulation difficulties. To reproduce the original phasing beforereversing a cutter head coil, one channel of the playback cartridge is reversed by the manu-facturer. Thus, in -phase mechanical forces result in out -of -phase electrical signals, and vice -versa.

chanical energy to the cartridgeelements (where mechanical energyis converted to electrical energy)stereo cartridges must respond tohorizontal and vertical motion.

The stylus displacement, andtherefore pressure or position ofthe cartridge's internal elements, isbased on combined mechanicalforces, as shown in Fig. 1. In -phasemechanical forces, that is both rec-ord groove sidewalls exerting ei-ther an upward -diagonal or down-ward diagonal force, will displacethe stylus vertically. Out -of -phaseforces occur when one sidewallexerts a down -diagonal pressureand the other sidewall an upward -diagonal force; or vice -versa. Thisresults in horizontal stylus dis-placement.

To achieve the RIAA's recom-mendation of equal in -phase sig-nals causing lateral modulation ofthe record groove, the leads to oneof the record groove cutter head'scoils are reversed. Accordingly, theplayback cartridge terminals are,or should be, reversed in phase bythe manufacturer. Consequently,the playback cartridge reproducesa mechanical in -phase signal witha lateral motion instead of a verti-cal motion (see Fig. 2).

Stereo cartridges can play mono-phonic records, also. Since verticalmotion is not employed in monogrooves the cartridge should bemade insensitive to it. This is ac-complished by a switching arrange-ment incorporated in most modernpreamplifiers or control sections.

The stereo cartridge elements areconnected in parallel, enabling thecartridge to combine lateral infor-mation, yet be insensitive to verti-cal information. (Equal and oppo-site voltages cancel each other.)

Specifications

Most stereo cartridge/stylusspec terms remain essentially thesame as their mono counterparts.A new specification, however, wasintroduced for stereo-channelseparation. Since two channels areactivated by one stylus, a degree ofcross -talk exists (audio of onechannel appearing in the otherchannel, or vice -versa). In otherwords, cross -talk states how welleach channel's sound is separatedfrom the other. A 20 db or greaterchannel separation is consideredadequate for minimum cross -talk.

Although other specification ter-minology remains the same, nu-merically they differ. Stylus pres-sures, for example, have undergoneradical changes. Today, a styluspressure of two or three grams isnot uncommon. In pre -stereo daysthis would have been fantastic.

Compliance, although not a newterm, is a commonly used one to-day. It indicates the amount ofstylus movement per one dynepressure. High compliance permitslighter tracking. Mono cartridgesneeded only lateral compliance,since vertical force signals were un-necessary. Stereo cartridges, how -



CHANNEL 1

8 11

anon

CHANNEL#2

1611 o811 o

1611

LIVINGROOM

DEN

KITCHEN

POWER DISTRIBUTION TABLE

LOCATIONSPEAKER

IMPEDANCEAMPLIFIERTAP USED

PROPORTION OFTOTAL POWER

LIVING RM. 16n 8n .5

DEN 1611 4n .25KITCHEN 16n 4n .25

1.00

Fig. 1-Arrangement for connecting threespeakers to a stereo amplifier's output forproper division of power and correct imped-ance match. For stereo, three additional speak-ers are connected to the second channel.

16 Il

CHANNELA

AMPLIFIER

CHANNEL

BAMPLIFIER

Fig. 2-Connecting one remote speaker tocombine left and right channel outputs.

AUDIOGENERATOR VTVM

Fig. 3-Test set-up for determining a speaker'sresonant frequency. Speaker is removed fromenclosure. Cone faces upward on bench.

92

Loudspeaker

Installation ProblemsEnclosure Tuning & Multiple Speaker Feeds

Are Some Of The Tasks ConfrontingTechnicians Today

Recurrent problems concerningspeakers can be disturbing, espe-cially if the answers are not athand. Some of these problems al-most always include the following:multiple feeds, electrostatics, fus-ing, and baffle tuning.

Multiple Feeds

After getting stereo in the livingroom, many people would like tohave extra speakers so they can lis-ten to it in a dining room, bedroomor any other part of the house.

An important consideration hereis having an amplifier with sufficientpower to drive all speakers at once,if required. Since most remotespeakers are high -efficiency types,this doesn't present any difficultiesto today's high power amplifiers. Ifa low -efficiency speaker is beingused, though, be sure the amplifiercan drive it adequately when allthe other speakers are employed.

Multiple output connections canbe arranged so: (a) each speakergets a proportion of the total pow-er to give equal apparent loudnessin each room, and (b) the overallmatching on the amplifier is cor-rect, so it can deliver its ratedmaximum. See Fig. 1.

The remote speakers can beturned "on" or "off" by a few meth-ods. A simple on -off switch may beused, connecting a dummy loadresistor to the "off" position circuit.The proportion of power going tothe speaker will be maintained.This makes the amplifier deliver itsfull power, regardless of how manyspeakers are working ... evenwhen they're all off !

Another connection method thatcan be used is the "L" or "T" padsystem, whereby each speaker's

volume can be individually con-trolled without changing the im-pedance match to the amplifier.Each attenuator-speaker combina-tion draws a constant proportion ofpower. Pads are available in 4, 8,and 16 ohm impedances and variouswattage ratings.

Although stereo hookups may berequested, the probable customerdesire is often a less elaborate one;a mono speaker for the remotespeaker. This could be accom-plished by tapping both channels,consequently feeding both signalsinto one speaker, as shown in Fig. 2.

Electrostatics

What's the "electrostatic" speak-er story? Apart from the fact thatthey work and can give quite goodreproduction, there is still a ques-tion of whether a particular ampli-fier can drive them. Many ampli-fier makers test for this by connect-ing a capacitor across the output. Ifthe amplifier works without break-ing into oscillation, it may be ratedsuitable for driving electrostatics.

An electrostatic speaker, thoughno more likely than a dynamicspeaker to cause an amplifier to be-have badly, should be checkedwith the intended amplifier.

Fusing

What about fusing to protectloudspeaker voice coils from blow-out? If someone, say a child, turnsup the volume control so that theamplifier is driving the speaker atfull power, the speaker's voice coilmay be burned out if the wattagegreatly exceeds speaker designlimits. Ohm's Law enables the tech -

(Continued on page 94)For more data, circle 9-93-1 on coupon, p. 78 -3.ELECTRONIC TECHNICIAN September, 1960

The Garrard Laboratories Proudly Announce an Entirely New Kind of Record Playing Unit

AN AUTOMATIC

TURNTABLEGARKAK1

1a80Ra10Av

SERIES

Now, at last, you can enjoy all the advantages of atrue, dynamically -balanced tone -arm (with a built-in calibratedpressure gauge), a full-size, heavy -weight professional turn-table, a laboratory -balanced precision motor...plus the much -wanted convenience of the world's finest automatic record-player...all in one superb instrument! p No one but the Garrard

THE ONLY DYNAMICALLY -BALANCED TONE ARM ON ANAUTOMATIC UNIT Now, for the first time, a tone armwhich meets the very latest engineering standardsestablished by the Industry-has been incorporatedinto an integrated record -playing unit. This highlyadvanced tone arm is put in perfect dynamic balanceby moving an adjustable counterweight. At this point,it is in "gyroscopic" balance, with zero pressure. Toset the tracking pressure designated for any cart-ridge, a pointer is moved along a calibrated scale atthe side of the arm which is graduated in grams. Thisbuilt-in stylus pressure gauge now shows the precisetracking force. The accuracy of this setting is evengreater than that which could be measured by anyseparate stylus pressure gauge. The arm will nowtrack correctly even if the player is intentionallytilted, or if the record is warped or not perfectlyconcentric.

And incidentally, regardless of the number of recordson the turntable, the angle at which the stylus meetsthe record is negligible, due to the unique geometryof this arm. A Since all of these engineering re-quirements guarantee that there is no unequal pres-sure on the sides of the stereo record grooves...distortion, channel imbalance, record and stylus wearare eliminated, resulting in perfect stereo reproduc-tion. But "perfect performance" also requires mini-mum friction, and this is assured by the twoprecision needle pivots on which the arm is set. Thisarm is precision -mounted for you, thus affording allthe advantages of the separate arm, yet none of itsinherent disadvantages. Thedanger of the tracking errorwhich often occurs in themounting of separate tonearms, is eliminated com-pletely because there is nopossibility of even the slight-est mislocation of the arm.

FULL-SIZED, HEAVILY WEIGHTED, BALANCED, CAST, POL-ISHED TURNTABLE The weight of six pounds has beendetermined as the optimum for perfect balance,

Laboratories, with their unmatched facilities, could have ac-complished it. With 40 years of manufacturing experience, andthe highest engineering and precision standards in the Industry,Garrard set out to develop an all -in -one unit that would satisfyevery critical requirement, even surpassing the professionalturntable standards established by the NARTB.

torque and flywheel action in this unit. This combina-tion insures silent, on -speed running. The Garrardengineers have conceived of this new turntable as a"sandwich". It is actually two turntables balancedtogether...a drive table inside, and a heavy, castturntable outside. The two turntables are separated bya resilient foam barrier, which effectively damps outany possibility of noise orvibration. Furthermore,being of non-ferrous metal,

at-traction to sensitive mag-netic pickups.

NEW "LABORATORY SERIES" MOTOR The Type A isbuilt around a newly -developed Garrard four -poleshaded motor, which was designed especially for it.This laboratory motor is the perfect match for the newturntable system, and provides quiet accuracy, re-gardless of load or voltage changes. Constancy ofspeed is such that this motor will bear the closestscrutiny by sensitive measuring instruments. The arma-ture is micro -balanced on exclusive Garrard equip-ment, and free of vibration. The total result is truemusical pitch and clear sustained musical passages,without the irritation of wow or flutter. The "Labora-tory Series" motor is completely shielded, top andbottom, with specially -designed and accurately orientedplates, insuring the absence of hum,even with the most sensitive magneticpickups. To minimize even the slightest ,vibrations, the entire motor assembly '.is isolated from the unit by shockmounts of a special formula and design.

THE GREAT PLUS FEATURE OF AUTOMATIC PLAY-WITH-OUT COMPROMISE! The convenience and desirabilityof being able to play records automatically, and tohave the unit shut itself off, have long been recognizedand accepted. Certainly, even the most critical userwould want these features, but only if they could beincorporated without compromising the quality, per-formance or inducing record wear. This has now beenaccomplished in the Type A, by adding Garrard's ex-clusive pusher platform changing mechanism, with itssmooth, one-piece center spindle, to the arm, turn-table and motor described above. This unique com-

bination of features meansthat for the first time ever,there is a record playing unitwhich answers every require-ment of both performanceand convenience. It accomplishes this to such a de-gree that it is certain to appeal to every person,regardless of whether he already owns equipment, oris planning to buy a new system. The fact is that theType A obsoletes all previous equipment. It protects

better, It has performance and featuressuperior to separate turntables and arms. It also in-corporates professional characteristics not found inany record changers.

The concept of this great new Garrard record -playingunit was extravagant, but the price of

$ e a 50is surprisingly modest-made possibleonly because of Garrard's extensive facilities, highlydeveloped production methods and critical qualitycontrol procedures. A If there ever was a singlerecord -playing device which answered every require-ment of every music system-we believe this is it.A And with the Type A, once and for all let us lay theghost that simply because a record player makes avail-able certain automatic conveniences (which you mayor may not use at your option)-that this in any wayimplies that the unit cannot be actually superior to aseparate turntable and arm. A For in this bold newunit you will find the realization of everything youhave wanted in a record player. Examine it thoroughly,and you'll want to install the Garrard Laboratory SeriesType A in your own music system-now. A Your dealerhas-or soon will receive-the LABORATORY SERIESTYPE A GARRARD. Let your own eyes and your ownsearching examination, prove beyond doubt that thisis indeed the record player for you. Or, if you prefer,write today for illustrated, descriptive booklet.

aizia ari.dWrite Department GM -550

Garrard Division of British Industries Corporation,Port Washington, New York.

There's a Garrard for every high fidelity system...all engineered and wired for Stereo

Type AAutomaticTurntable$69.50

RC88DeluxeChanger$59.50

Model 210Deluxe Intermix ,.Changer$49.50

301 ? 4HFTranscription 'Turntable

Transcriptionl ' Manual Player$89.00 f $59.50

and Monaural records.

Model TillManualPlayer$32.50

Canadian inquiries to Chas. W. Pointon, Ltd., 66 Racine Road, Rexdale. Ontario Territories other than U.S.A. and Canada to Garrard Engineering & Mfg. Co., Ltd.,Swindon, Mts., England

Loudspeaker

(Continued from page 92)nician to calculate the fuse amper-age necessary to protect a speakerunder these conditions.

A fuse, however, will not protecta speaker voice coil from burningout if excessive parasitic oscillationis present in the amplifier. Nor willsudden unusually large transientsblow-out the fuse. They may, how-ever, damage the voice coil con-nection by reason of the mechan-ical force they generate.

Baffle Tuning

Baffle tuning is a question oftenpresented by hi-fi technicians whodo custom installation work. Whatkind of speakers can be used to

SPEAKEREQUIPMENT

CABINET SPEAKER

(1) O O OIffill I-/FP)

POR

ADJUSTABLE (SLIDING)BLOCK OF WOOD

Fig. 4-Adjustable port -tuned enclosure forimproved speaker bass response. When properport opening is determined by adjusting thewood block, it should be secured in the sameposition inside the enclosure.

obtain high fidelity performance inan enclosure that doesn't match it?

The technician has three prac-tical choices : insert any popularspeaker and accept the perform-ance for what it is-less than opti-mum, place a bookshelf -type speak-er, enclosure and all, inside thecabinet, or try to match cabinetand speaker by converting thecabinet into a tuned baffle.

The first two choices are obvi-ously simple ... and inadequate.The latter choice is not as simple,but can result in satisfactory sound.Perhaps the easiest method toproperly baffle a speaker in an en-closure that has already been builtis to change the cabinet to a bass -reflex enclosure. The cabinet-mak-

AUDIOGENERATOR

40111 50'U52'0

SCOPE

54 ti

35'1" 43'U 48ti 51'U 54 Q.,

58'U 72'U56 PU

58'1) 62'1J 70'1) 85'u

Fig. 5-Test set-up with audio oscillator and scope for adjusting port. Note pattern's increasedamplitude as resonance (54 cps) is approached. The bottom row of patterns typify those obtainedwhen the port is correctly tuned.

The purpose of the tuned en-closure is to reinforce this resonantcurve, thereby flattening it and ex-tending the bass response. To ac-complish this, it will be necessaryto cut a port at the lower front sideof the enclosure. Arrange the open-ing to be adjustable, as shown inFig. 4.

A compatible port opening canbe determined by feeding thespeaker from an audio generatorthrough a series resistor, as shownin Fig. 5, and viewing the patternon a scope. At resonance, the trace


FREE AIR

RESONANCE

TUNED PORTRESONANCE

I I I j

20 40 80 100FREQUENCY

Fig. 6-Voltage-frequency resonance curve ofspeaker before and after adjusting port.

For more data, circle 9-95-1 on coupon, p. 78 -94 ELECTRONIC TECHNICIAN September, 1960

er's responsibility is to build a cabi-net that can withstand the tremen-dous sound pressures within it byusing at least 3/4" plywood andproper bracing and damping ma-terial. The technician's responsibil-ity is to select a speaker that willoperate well in the allotted cabinetspace. Speaker manufacturers canhelp here.

Once the speaker has been se-lected, it's a good idea to learn itsbass resonance point ; the lower thebetter (provided the cabinet islarge enough). The simple test set-up shown in Fig. 3 will determinethe speaker's resonant frequency.The series damping resistor shouldbe roughly 5 to 10 times the speak-er's impedance. Tuning the audiooscillator through a series of lowfrequencies, say, 30 cps through120 cps, at 10 cycle intervals, willenable the technician to plot a fre-quency graph. The resonant fre-quency will be indicated by themaximum peak voltage indicatedon the VTVM. Test is made outsidethe enclosure with the speaker conefacing open air.

the people who brought you the

L1f

LIFETIMEGUARANTEE

TKE lace freethis

¡lure

uta

loud-

speaker

reneto anyew or reerform0 o

failureoriginal

speaker due during the lifetime handling,

M any timecharge

ma or

materials or servicing orowner. Malabo Customer Pays

inspection, orreplacement.

any repairpostage only.

MORE POWER

PER POUND

SPEAKER now offer

MORE SOUND

PER LIFE

in the revolutionary

LIFETIME

SPEAKERguaranteed

for the life of the owner24 hours a day, we lay our reputation (andour profits) on the block! We guarantee per-fection of performance for a lifetime. Todo this, we have to make the speakers of ourlifetime ... and we do!

Order a Utah Lifetime for your next re-placement and see! (All popular sizes andshapes).

Utah Radio á Electronic Corp., Huntington.1nt;

the ultimate ina dynamically -

balanced

tonearm

NEW

REKTM

Model S-22012" arm

$2995net

PLUS THESE EXTRA FEATURES...

Acoustically isolated counterweight.

Exclusive precision low friction Sili-cone damped horizontal bearing -eliminates horizontal oscillation.

Exclusive gimbal assembly incorpo-rates individual double sets of 5 ball,1 mm. bearings - provides freestlateral and vertical motion and as-sures perfect tracking.

Plus many other exclusive Rek-O-Kutfeatures.Model S-260 16" arm 34.95 netExtra Stereo Shell-

Model PS -20L 5.95Still available-Model S-120...12" arm Now 24.95 NetModel S-160...16" arm... Now 27.95 net

STEREO TONEARMwith superb new featu .es for higher

playback quality and in.itallation ease:

MICROPOISE DYNAMIC

BALANCE CONTROL-By di<ling

the cushioned, spring -tension

Microscope Balance Contrc I,the arm is dynamicallybalanced and set for accu-atestylus pressure:

PERMANENTLY ATTACHED

PLUG-IN CABLE-fully shiededsingle -jacket cable is anchc red

to the arm-includes twocolor -coded plug-in leads,

2 shields and a ground wire.No soldering! No humproblem! Fast, correctinstallation assured!

FAST SINGLE -HOLE MOUNTING:

Arm base mounts throughsingle hole by tighteningof single locknut.

Revolutionary automaticcontrol accommodating theS-220 will soon be announced!

Rek-O-Kut Company, Inc., Dept. ET -A38-19 108th St., Corona 68, N. Y.

Please send me free brochure:

Name

Address

City Zone State

Export: Morhan Exporting Corp. 458 Broadway, N. Y. 13.Canada: Atlas Radio, 50 Wingold Ave., Toronto 19.

Loudspeaker

(Continued from page 94)

will swing 'round rapidly and peakup vertically. Proper port adjust-ment should affect this in two ways :(1) the resonance should be as lowin frequency as possible, and (2)the vertical rise due to resonancepeaking should not be as severe aswithout the port. This can bechecked by closing the port com-pletely and noting the difference inthe scope trace. When the properport opening is obtained, duplicatethe amount of port closing at theinterior side of the port with ablock of wood. Repeat this proce-dure with the second speaker en-closure, also.

Another bass -reflex enclosure tun-ing method can be employed by us-ing an a -c voltmeter across thespeaker's voice coil, as shown inFig. 3. Here, a constant voltageaudio signal is again swept throughvaried bass frequencies. The woodblock that varies the port openingsize is adjusted until the smoothestmeter reading is noted. When thisoccurs, transfer the wood block tothe inside of the enclosure, main-taining the accepted port size.

A voltage rise will be detected atthe speaker's resonant frequency.The port should be adjusted for thelowest, flattest response. Fig. 6 il-lustrates an idealized final responsecurve in a properly tuned bass -re-flex enclosure compared to the high-ly -peaked resonant frequency whenthe enclosure is untuned. Actualcurves will, naturally, be jaggedrather than the idealized smoothcurve shown.

Be sure that no enclosure air leaksexist when making tests except forthe port opening. The enclosureback should be sealed with at least34" plywood and secured tightlywith screws.

F For more data, circle 9-96-1 on coupon, p. 78

JE 1RO LO

tROUDLY PRESENTIN,ó ...

magic carpet4)-.'Y, FM antenna

Now! Provide your customerswith the most exciting newconcept in FM reception in tenyears. A precision -designed,printed -circuit indoor antennathat produces receptioncomparable to what couldpreviously be achieved only byusing outdoor antenna equipment.Gone are unsightly, expensiveand hazardous rooftop antennas.Banished are ugly indoor devices.With the "Magic Carpet"antenna your customers willenjoy twice the gain of a singlebay turnstile outdoor antenna ata fraction of the cost. And hisFM signals will come throughbrilliantly and reliably withoutdistortion or noise.What's more, with a JERROLDTV -FM frequency -sensitivecoupler (Model TX -FM) you canalso assure excellent TV receptionfrom the same "Magic Carpet"antenna without loss to eithersignal ... allow simultaneousoperation of both sets.The "Magic Carpet" opens up awhole new and profitable marketfor you. It takes but a simpledemonstration to sell it.

JERROID

$9.95 list

ELECTRON ICS

)fFI 111111)

1Fltltl

magic carpet`

carpet*antenna.1/ 0.1-ffr 11 a OK* IMMT.111 C.1131491

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Write for complete details and catalog showingthe entire line of Jerrold reception aids .. .

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1

For more data, circle 9-97-1 on coupon, p. 7dELECTRONIC TECHNICIAN September, 1960 97

Status Of Stereo BroadcastingNumerous Stereocasting Systems Tested & Evaluated By Industry

Committee For Recommendation To FCC

Tuner and receiver manufactur-ers, as well as the stereo -mindedpublic, are anxiously awaiting theFCC's decision regarding the ac-cepted stereo transmission method.Many systems have been proposedand, obviously, a system cannot beadopted without considerable pre-liminary investigation.

As an example, the National Ster-eophonic Radio Committee hasevaluated 4 FM/FM, 7 FM/AM and7 AM stereo multiplexing systems.

Multiplexing Systems

The three FM/FM proposals, ex-cluding the Percival (EMI) sys-tem, differ primarily in the band-width allotted for the subcarrier.These are the Calbest, Halstead, andCrosby systems.

The Calbest multiplexing system,as shown in Fig. 1, adds a sub -car-rier frequency to the MX oscillator

tuned circuit plus the standard 455kc i -f frequency, and the discrimin-ator transformer is tuned to thesub -carrier frequency. The 25 to 75kc FM multiplex sub -carrier istuned.

In the Halstead method, as shownin the simplified diagram at Fig. 2,one wide band and one narrow bandchannel is used. The system does notgive full fidelity and the stereo deptheffect is partly lost.

Using the sum and difference fre-quency principle as carriers for themultiplex stereo signal, the Crosbysystem (Fig. 3), appears to be aleading contender for selection asthe accepted method.

The Percival system (EMI) em-ploys a form of coded stereo and isconsidered by some as a possible al-ternative to the Crosby system. Thereceiver has a signal containing theaudio frequency plus 22 kc coupledto the amplifier rectifier. This sig-

Fig. 1-Simplified schematic of the Calbest multiplexing system which adds a sub -carrier to themultiplex oscillator circuit plus the standard 455 kc i -f frequency. Discriminator transformer istuned to subcarrier frequency.

MX INFROM

MAIN DET

Y

11

10.7 PRIMARY

455 455

10.7 XFORMERSECONDARY

MX LIMITER

MX OSC.455 (SUBCARRIER`' KC +455 KC)-

bT\SUBCARR IER

TUNE TO - 1.11

MX AUDIOOUT

98

TUNER

AUDIO

OUTPUT

MULTI-PLEX

DEMODULATOR

FULL

FIDELITY

NARROW

BAND

SPEAKERS

1:14

Fig. 2-Functional diagram of Halstead sys-tem which employs a wide and a narrowband channel.

nal is divided into two frequenciesafter passing through the Hall mul-tiplier, with the outputs fed to theleft and right channel amplifiers. Aswe know, this system was developed

England and has been tested bythe B.B.C. The NSRC has indicatedsome reservations about the system.

As previously mentioned, thereare 7 FM/AM systems under con-sideration: GE employs a full AMsubcarrier, Philco a S.S.B. modu-lated subcarrier system with thesubcarrier nearly suppressed. Othersystems involved are the RCA, Zen-ith, Volpe, Svorec, Nealy and Lip-pencott. The system designed byRCA is shown in Fig. 4. In thismethod the incoming signal istapped after the i -f amplifier andpart is fed to the FM detector whilethe main signal goes to the matrixnetwork. After de -emphasis, the de-tected signal is also fed to the ma-trix stage and its output is fed toamplifier one as A + B, while thesignal for channel 2 is A-B.

Testing of the Halstead, Calbest,Zenith, Crosby, GE, and EMI stereoreceivers was performed this sum-mer. Units were checked for fre-quency response, separation, dis-tortion, s/n ratio, subjective evalu-ation, cross -talk, r -f spectrum, andease of tuning. In addition to elec-tronic tests, mechanical design andstructure was evaluated and given

(Continued on page 100)For more data, circle 9-99-1 on coupon, p. 78>


UP TO FOUR TIMES THE WORKING DISTANCE OF CARDIOID TYPES* with the Electro -Voice model 644 sound spot

)f all the audio problems confronting sound engineers, one of the most difficult to overcome is the use of microphones in spacious areas.Turches, auditoriums and amphitheaters present formidable problems in room acoustics and reverberation which degrade audio quality.:onsequently, microphones cannot be graced at conventional distances from the source of sound. Under such conditions, loss of level and'presence" further add to the enigma of proper pick-up. The Model 644 Sound Spot is the answer. Here is a microphone providing acceptancevithin an included angle of 900 at high frequencies, high axial sensitivity, wide frequency response extending from 40 to 12,000 cps and excellentvind noise cancelling characteristics. Its highly directional feature permits unusual microphone working distances as well as startling flexibilityn loudspeaker placement. Effective cancellation of sound at the rear and sides for unparalleled rejection of random noise, reverberation and feed -tack without frequency response loss. See Polar Pattern. Stop at your Electro -Voice distributor today and let him demonstrate the Model 644.Depending on Acoustical conditions.

ither features: Output level -53 db. 150 ohm and high impedance. Impedance changed byloving one connection to connector. Low impedance only: line balanced to ground andhased. Acoustalloy diaphragm, shielded from dust and magnetic particles. Non -welded Polarircuit with Alnico V and Armco magnetic iron. Pressure cast case. %"-27 thread. Satin Pattern ,j>/, Commercial Products Divisionhrome finish. 18 ft. cable with MC4M connector. ON -OFF switch. Size: 2fá" diam. 16" length. ELECTRO -VOICE, INC.let Wt.: 2 lb. 9 oz. less cable. List Price $110.00. Desk stand available (extra). Dept. 90T Buchanan, Michigan.

Elecyfor'cne

rFM RECEIVER

(A+B) + (A -B) (A+B)+(A-B)

FRONT11."AMPU- 01"TECDETECTORFI

L

DE -EMPHASISNETWORK

H FILTERII

A -B -(A-B)¡ (A+B)-(A-B)=2E\I MULTIPLEX ADAPTER

(A+B) + (A -B) -zA

rAUDIOAMPLIFIER -

A-B A+B

DEMOD- y PHASE ULATOR T INVERTER

AUDIO

AMPLIFIER

Fig. 3-Functional diagram of Crosby system showing multiplex adapter connected from dis-criminator output. Proposal uses a sum and difference frequency system for stereo reception.

(Continued from page 98)strenuous tests. Each unit was alsochecked for field strength, reactionto airplane flutter, noise ejectionand ability to reject interference.

The stereo transmitter used atest tape that put each receiverthrough a rigorous aural test ob-served by a panel of distinguishedexperts in the field. Naturally, thepanel was briefed on the testingprocedure used and informed re-garding variations to expect in testtransmissions.

The following is an example ofexerpts from actual test tape:"Stereo test 4: Over the course of atwo minute duration the tape trans-mission will shift from straightstereo to stereo with a modificationadded. The shifts will appear atfive second intervals. In this testthe low frequencies are processedand will appear to originate fromthe speaker closest to the listener.In the case where the speakers areequi-distant, the sound will appearto originate from some point be-tween the two speakers." Listenerswere seated about 10 feet awayfrom a pair of loudspeakers 7 feetapart.

Other tests included processingof high frequencies and mixture ofboth signals. The panel listenerswere advised of the manner of pres-entation, before each test, and thedeviation from straight stereo tomultiplexing appeared in a seriesof regular and precise intervals. Inaddition to pre -performance an-nouncements of mixed transmis-sion, each participant was providedwith a clock indicating five and ten -second durations for normal andmultiplex stereo operation.

Instrumentation for the afore-mentioned tests was elaborate. Thisequipment included :

1. Ampex stereo recorders

2. H -P VTVM Model 4003. H -P Distortion Analyzer Model 3304. H -P wave analyzer Model 3025. Stereo monitor amplifier and speaker6. RCA field strength meter Model

BW-77. Boonton FM Signal generator Model

2028. Measurements FM signal generator

Model 210

Some deplore the delay in reach-ing decisions about stereocasting.It could be infinitely worse, how-ever, to have the wrong decisionsmade in a hurry. All of the variousproposals must be properly evaluat-ed to determine what system has thebest prospects; both immediate andfuture potential.

A comprehensive report pub-lished in Britain sees the Crosbysystem as the only sensible multi-plex contender. There, the Percivalsystem is considered an alternativeto Crosby multiplex.

Fig. 4-System developed by RCA employsA 7 B and A B information for two chan-nel stereo reception.

AMP MIXER AMP

AMDETECTOR

A+B4 MATRIX

FM DETECTOR I f

6 DEEMPHASIS A -B

`-- AF AMPLIFIER- AFAMPLIFIER

DEMOD-ULATOR

OUTPUT

CONVENTIONALAUDIO OUTPUT,WITH OR WITHOUT

CATHODE FOLLOWER

DE EMPHASISNETWORK"

MULTIPLEX OUTPUT,WHERE PROVIDED

Fig. 5-Basic circuit of provision for multi-plex in some tuners. An adapter is neededfor whatever system is accepted.

What will be needed to make con-version when the time comes ? Tun-ers presently on the market makevarious claims about adaptabilityto multiplex. What do these claimsmean?

Actually, conversion to multiplexstereo, whether sum -and -differenceCrosby type, or the coded Percivaltype, is not too difficult with anytuner of reasonable quality. Someunits provide a separate outputsocket for multiple operation, asshown in Fig. 5. This is variouslycalled : "providing for multiplex,""adaptable to multiplex," etc. Thisextra output socket is merely a con-nection ahead of the de -emphasisnetwork. A multiplex adapter willstill be needed to suit whatever typeof multiplex operation is eventuallyapproved.

A tuner that does not have thisspecific output socket can also beused (see Fig. 6) by tapping inahead of the de -emphasis, or by us-ing a simple R -C pre -emphasis com-bination to restore the proper char-acteristic needed to complete thestereo conversion. Either way, theadapter is needed to complete theconversion, plus the rest of a stereosystem, of course.

Fig. 6-It's not necessary to internally modifya tuner not provided with a conversionadapter output. The network shown here canbe used externally. The multiplex adapter,however, needs about 20 db more gain.


How 8,600 electronic servicemenmade an extra x1,500 per ,year

`Electronic Technician' research reveals important side income from sale of sound equipment

Now, pre -planned Signet Sound Pit easy for any servicemen to move

All you need is a sharp eye and a Signet catalog.Armed with these you'll have no problem discoveringthe innumerable profit opportunities all around you.

Start to add up the hundreds of meeting halls,smaller churches, sports and social clubs or fraterni-ties, taverns, restaurants in your area. Don't forgetfamilies who are proud of their outdoor entertaining.

Consider this fact. Few people know about sound.Even less realize its convenience and effectiveness...and how little it costs.

And this is where you come in. You are the pro-fessional.. accepted expert in your community.You can point out the benefits of sound and offerprofessional equipment, expertly engineered byStromberg-Carlson - the greatest name in sound.

You can offer a complete choice-size and price -wise - of pre -planned ready -to -install Signet SoundPackages. All you need is the catalog.

For more data, circleELECTRONIC TECHNICIAN September, 1960

ackages by Stromberg-Carlson makein on a profitable, expanding market.

You earn a good profit on the equipment and getpaid for installing it. And nothing is easier to installthan Signet Sound. Result ... for comparativelylittle effort you pocket between $40 and $200 spare-time profit on each installation.

Is it as easy as it sounds ? Yes. Especially withSignet Sound Packages. Electronic Technician Mag-azine showed that Servicemen sold over Sixty-fourmillion dollars worth of this type of sound equip-ment and service during 1958. And considerablymore equipment has been sold this year.

It will pay you to write for detailed informationand the Signet Sound Catalog to:

Commercial Products Division,1474-09 North Goodman Street,

Rochester 3, New York.

STROM BERG -CARLSONA DIVISION OF GENERAL DYNAMICS

9-101-1 on coupon, p. 78101

Stereo Changers, Players &Turntables

A Mechanical Profile Of Stereo Record Playing Equipment

Fig. 1-Some examples of drive devices usedto rotate disc turntables are shown here.

MOTOR SHAFT

IDLER TURNTABLE

GUMRUBBERTYPEDRIVE

TURNTABLE

0

TURN--.TABLE

MOTOR SHAFT

STEP PULLEY

IDLER

IDLER

TURNTABLE

MOTORSHAFT

TURNTABLE

CONICAL MOTOR SHAFT

Record changers, players, turn-tables, and their respective tonearms are the mechanical accompa-niments of any disc playing system,whether mono or stereo. Stereo justmakes the equipment requirementsa little more rigorous.

The concept of stereo sound andincreased high fidelity consciousnessof our citizenry had a profound ef-fect on disc -rotating equipment.Record changers, for example, nowinvariably incorporate a mechani-cal switch to disengage its changermechanism; in effect, allowing thechanger to be employed as a man-ual player.

Aside from many record changerand turntable innovations since1958, we witnessed the emergenceof another major product-recordplayers. Not the pre -stereo recordplayers that were actually recordchangers minus changing mecha-nisms, but units that offer, in manyinstances, turntable performance,and the convenience of a pre -mounted professional -type tonearm. In fact, some of the "players"are top -grade turntables that incor-porate a matched professional tonearm. This relieves purchasers ofdrilling mounting holes and posi-tioning a separate tone arm, thoughrestricting selection of a specifictonearm.

Turntable Drives

The turntable drive types usedwith these players are interestingfrom an operational and serviceviewpoint. Whereas record chang-ers have essentially maintained theidler -type drive system shown inFig. 1A, players have adapted bothrecord changer and turntable drivesystems : idler drive and idler driveor belt drive, respectively. The lat-ter, belt drive, is illustrated in Fig.1B. In addition, other type drivesare being used, such as those shownin Figs. 1C through 1E.

Variations of the aforementioneddrives are, of course, also used. Oneleading turntable manufacturer

Mechanical Sources

Motive DeviceChangerPlayerTurntable

Tone -Arm

Pre -assembled

SeparateIntegrated

uses twin precision idler wheels toobtain accurate speed for 33% and45 rpm speeds, as opposed to oneidler wheel and a step pulley ar-

changing speeds.It is a simple matter to replace

idler wheels when their rubber rimsdevelop "flats," glazed hardness, orunusual wear, resulting in wow, flut-ter or incorrect speeds. The same istrue of worn and frayed belts.

Idler wheels, or pucks, can wearout -of -round by skidding if theturntable is stopped forcibly whilethe drive is running, or by being leftwith pressure on one spot when notrunning. A puck drive should bedisengaged when it is not driving;either automatically or manually.Belts can stretch unevenly, so they"warp," causing them to ride errati-cally.

When servicing, never, underany circumstances, apply oil orgrease to idlers, belts, or turntablerims. These areas should be cleanedwith denatured alcohol to removeany accumulated grime.

As far as record changers are con-cerned, careful design has upgrad-ed changers so they compare favor-ably with many turntables. Thesame drive problems exist with rec-ord changers as with players andturntables. Added to the potentialbreakdown list, however, are nu-merous mechanical linkages thatcan frustrate a mechanical engi-neer. Service literature and practi-



0411, W, o O4° Q ALL -NEW V -M TAPE RECORDER RECORDSSTEREOPHONICALLY! UNIQUE V -M"ADD -A -TRACK" FEATURE! 4 -TRACKMONOPHONIC RECORD and PLAY!Here's V -M's newest and by far, most versatile taperecorder! V -M Model 722 `tape-o-matic'® PortableTape Recorder, in addition to "Add -A -Track," re-cords stereophonically, too! Unique V -M "Add -A -Track" feature enables you to record on one track,rewind, add additional voices or accompaniment on asecond track while listening to the first track! Onplay -back both recordings are heard simultaneously!High -Fidelity Speaker System $259.95 List*

V-M/'tape-o-matic® 4 -Track Stereo Record/Play TapeRecorder-Model 722V-M/StereoVoice Auxiliary Amplifier-Speaker-Model168 Completes the stereo system $75.00 List*

V -M PRECISION RECORD CHANGERS DE-SIGNED TO SELL IN VOLUME!Acclaimed the world's finest changers! Play all recordsizes and speeds both stereo and monophonic! DIAMOND NEEDLE INCLUDED (Models 1571, 1586) EXCLUSIVE V -M TRI-O-MATIc'® SPINDLE PROFESSIONALLY MASSIVE I I* TURNTABLE NEW AUTOMATIC MANUAL -PLAY FEATURE EXTRA LONG, DYNAMICALLY BALANCED, NON -

RESONANT TONE ARM NEW SCIENTIFICALLY PRECISE TURNTABLE BEARING

SYSTEM

V-M/Deluxe 'Stere-O-Matic'® 4 -Speed RecordChanger with Cartridge and Diamond Needle!-Model 1571 (Shown with Accessory 45 spindle adap-tor)-Available with 4 -pole motor and plug-in tonearm head for magnetic cartridges as Model 1572.Model 1586 is Model 1571 mounted on a base. Model1587 is Model 1572 mounted on a base.Models 1571, 1572 $50.00 List*Models 1586, 1587 ;56.00 List*

V-M/High-Fidelity Custom Turntable-Model 1580-Comes complete with diamond needle stereo car-tridge. New, massive eleven -inch turntable for custominstallations. Special stereo motor. Micro -precisionturntable bearing system with Teflon thrust bearing.Special V -M 45 rpm insert spindle $35.00 List*

INCREASE YOUR SALES VOLUME AND INSPIRECUSTOMER SATISFACTION-PROMOTE AND SELLAMERICA'S MOST POPULAR TAPE RECORDERSAND QUALITY COMPONENTS! Slightly Higher West

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For more data, circle 9-103-1 on coupon p. 78ELECTRONIC TECHNICIAN September, 1960 103

Analyzing Stereo Tape Equipment

SUPPLY

GUIDEPOST

TAKEUP

HEADSCAPSTAN

GUIDEPRESSURE POST

PADS PRESSUREROLLER

Fig. 1-Basic top -deck components of a typi-cal tape recorder. The capstan-not the take-up reel-pulls the tape past the heads. Thetakeup reel employs a slipping clutch systemto evenly wind used tape around its hub.

RECORD -PLAYBACK

PLAYBACKAMPLIFIER

RECORDAMPLIFIER

ERASE

BIASOSC.

Fig. 2-Electronic blocks of a tape recorder.Four -track stereo players employ twin ampli-fiers and oscillators, plus quadruple gaps andseparate channel windings.

Fig. 3-Test set-up for checking head align-ment employing a -c voltmeter and test tape.Following manufacturer's recommendations,head bracket screws are adjusted for maxi-mum voltage reading.

MAXIMUMOUTPUT

CORRECTAZIMUTH

ALIGNMENT

EXAGGERATEDAZIMUTH

DEVIATIONc, '~11111E11111

TAPE HEAD GAPS

p®40TAPE RECORDER

LOADRESISTOR

OUTPUT

Cartridge Innovations And 4 -Track TapeDraw Interest. Correcting MechanicalDefects Is A Key Service Problem

The tape equipment sales reces-sion during the early days of stereodiscs is past history. Introductionof four -track tape and agreementamong most recording companiesto merchandise 71/2 ips pre-record-ed tape through a central organiza-tion, United Stereo Tape, madesales figures respectable again.

Reel-to-reel four -track tapeequipment is the major seller. Mostreel-to-reel tape units incorporate33/4 and 71/2 ips speeds ; some alsoinclude a 17/8 speed. The funda-mental reel-to-reel tape handlingmethods and electronic circuitblocks are maintained in four -trackequipment, as shown in Figs. 1 and2.

Reel -To -Reel Operation

A full reel of tape is placed onthe supply spindle and the tape isplaced through an inline slot andthreaded on an empty takeup reel.And that's all there is to it!

The purpose of the tape han-dling mechanism is to feed the tapefrom the supply reel past the tapeheads to the takeup reel-at aconstant, unvarying speed. This isthe precision -like task of the cap-stan. The capstan pulls the tapepast the heads at a constant speed,aided by a pressure roller whichpresses the tape against the cap-stan for traction purposes. Pres-sure pads maintain the tape againstthe tape heads.

Cartridge TapesThe potential of "automatic"

tapes has yet to be fulfilled. The33/4 ips, four -track cartridge tapeplayback equipment didn't catchthe public eye. It's difficult to de-termine the specific reason for itsfailure thus far. Probably, it's due

to combined factors : unattractivepackaging, high relative cost, in-ability to record, only one majorsupplier of pre-recorded cartridgetape, early production "bugs," low-er speed (with less, though good,fidelity than 71/2 ips tapes) , strongcompetition by reel-to-reel manu-facturers.

But the cartridge tape prospectshave not diminished. In fact, an-other system has been introduced;a 17/s ips cartridge that can bestacked like discs on a recordchanger. The system is not yet inproduction.

The system employs three tracktape. Two tracks are used for ste-reo material, while the third track,located in the center of a 150 milwide tape, is intended to carry anoptional reverberation channel.

Fig. 4-Commonly used tape drive systems areshown here. A precision flywheel typically in-sures smoother capstan motion.

IDLERMOTORSHAFT

TAKE-UP REEL

FLYWHEEL

$AIAPS!N

TAKE-UP REEL

MOTORSHAFT


When the third track is used, it isplayed on one or more backgroundspeakers behind and around the au-dience. This adds reverberation ac-cording to the original program re-quirements, thereby simulatingconcert hall or auditorium effects.

ServiceHead -cleaning will be a service

needed for a while yet. This re-quires care and should be done withone of the cleaners made for thepurpose, not a wire brush or otherharsh agent that could spoil thehead. New tape material drastical-ly reduces the rate at which headsgum up.

Owners should clean their taperecorder heads after a few hoursplaying time. Unfortunately theydon't, though it's just as simple ascleaning a disc. When the headswear, the frequency response de-teriorates because of the wideninghead gap. Consequently, replace-ment is eventually required.

When servicing tape recorderstechnicians should check headalignment, both record -playbackand erase or any other head com-bination used, with a test tape.Alignment procedures vary andthe manufacturer's recommenda-tions should always be followed.The alignment set-up illustrated inFig. 3 is the basic method thatshould be used. Connect an a -cvoltmeter to the output of the taperecorder and, running the test tape,adjust the head bracket screws as

suggested by the manufacturer un-til maximum output voltage isreached.

Pressure pads are frequent of-fenders in tape recorders. Theirpurpose is to maintain the tapeagainst the head gaps and un -wrinkle it, if necessary. After aperiod of time, they will wear down.When this happens, the felt -likepads should be replaced to avoidpitting of the tape heads. Thismay be done with either a newpressure pad and arm, or, the paditself can be pried off and a newpad cemented in the exact sameposition as the old one. Check thepads to make sure they are proper-ly holding the tape against thehead.

Don't oil or grease the capstan,pressure roller, guide posts, or anyother surface that the recordingtapes will touch. Lubricants shouldbe used very sparingly since con-tact with rubber will underminethe mechanical purpose of a taperecorder's transport system.

Most performance inadequaciesof a tape recorder are related tomechanical deficiencies. They cantake the form of wow or flutter,incorrect speed, improper or notape movement, or rewind, or fast -forward, tape rubbing noise, me-chanical gear or drive noise, tapebreakage or spillage.

Observing the mechanical oper-ation of the various parts will bean invaluable aid in locating amechanical defect. Clutches,

Fig. 5-A motor test and repair bench illustrates the variety of motortypes employed in tape equipment.

brakes, drives, takeup tensions,and other mechanical parts willvary from make -to -make. Sometypical capstan drive systems areshown in Fig. 4. The varied motortypes employed is emphasized bythe motor test and repair benchphoto shown in Fig. 5. Mechanicaldifficulties cannot be solved as sim-ply as electronic problems. No easysolution is available, such as in-serting a signal to the input andnoting its output. The technician'sbasic "school" must be manufac-turers' service manuals and plentyof practical experience that can beacquired "on the bench" (see Fig.6).

There are relatively few top serv-ice specialists in the tape recorderfield. Yet, the average stereo taperecorder often costs more than aTV set. And since the initial costof the unit is high, customers areless inclined to refuse a job if theservice work warrants a relativelyhigh charge.

A prominent tape recorder man-ufacturer recently made a surveyconcerning tape recorder charges.The results of this survey indicatedan average minimum servicecharge on tape recorder repairs as :$7.50, with one company charging$9.00. The average per hour ratecharged, plus parts, is also $7.50,with one company charging $10.00per hour. And-customers bringtheir sets to the shop.

Illustration Credit: Sigma Elec-tric Co., New York, N. Y.

Fig. 6-Mechanical "know-how" for effective tape recorder servicingis obtained primarily on the work bench.


Evaluating Stereo PackagesStereo Portable & Console Analysis Provides An Illuminating

View Of Services, Sales, And New Developments

The person who buys compo-nent high fidelity stereo can selecteach component and thus "custombuild" a system. For many, how-ever, a package stereo system of-fers the better approach to stereo.The reason (s) for this choice mayvary : lower cost, compactness, aes-thetics, no confidence in own "hook-ups," unwillingness to pay extra forinstallation, confusion over separatecomponent selections, confidence ina "name" brand or retailer. What-ever the reason, though, stereopackages-from the inexpensivemanual player to the moderately

expensive console-are big sellers.As such, they are major servicemoney earners for technicians alertto their mass ownership.

Packages come in a very wideprice range. But price is not neces-sarily an index of quality. Manypackage set prices depend on howwell some non -manufacturing mer-chandisers have negotiated withthe suppliers who assemble the sets,profit structure of the company,how much added for "free service,"what type of cost cutting, etc.

As an example of good "basic"cost-cutting, take the newly devel-

Fig. 1-New stereo input and output circuits achieve push-pull output with only two tubes,instead of four, and one center -tapped transformer instead of two.

INPUT

mig awlSPECIALSTEREO

PICKUP

CONVENTIONALAMPL I FIER,WITH DUAL

VOLUME CONTROLS,TONE CONTROLS,

ETC.

OUTPUT

L2

s+

oped type of dual amplifier. It usespush-pull operation for the monopart of the program and push -pushto handle the stereo part. This ef-fects several economies, enablingcomparable quality to be achievedfor much less cost.

This modified form of a push-pullaudio output stage is shown in Fig.1. Unlike the usually designed push-pull output stage, "push-pull" isachieved with only one tube, ratherthan two tubes. Therefore, in astereo unit, only two tubes areneeded instead of the usual fourtubes-a saving of two tubes.

How It Works

Except for the cartridge connec-tions to the input tubes and the out-put circuit, everything in betweenis typical familiar circuitry. Revers-ing one channel's cartridge connec-tions, as shown in Fig. 2, changesour known phase development. In-stead of an out -of -phase signal pro-duced by a vertical cut and an in -

phase signal produced by a lateralcut, the reverse occurs : a verticalcut produces an in -phase signaland a lateral cut produces an out-of -phase signal. Consequently,when substituting cartridges, becertain to use either the exact re-


placement or a four -terminal one.This system uses what is some-

times called a double matrixingnetwork, composed of two outputtransformers. One operates in push-pull and the other in push -push.One speaker voice coil is reversedfor proper accoustical in -phase op-eration. In effect, by phase shift-ing, the sum and difference signalscan be recombined as right and leftsignals.

When a monophonic record isplayed, the system operates push-pull and both speakers receive andreproduce identical signals simul-taneously from the push-pull outputsecondary. No output is obtainedfrom the push -push transformer. Inthis case a switch should be usedto short out either the primary orsecondary of the push -push trans-former to eliminate any verticalcomponent such as rumble, etc.

When a stereo record is playedand in -phase signals appear on thetwo amplifier tube grids, they op-erate in push -push or parallel. Thetwo in -phase currents appearingacross both halves of the transform-er primary are cancelled at the cen-ter tap and no signal is induced inthe secondary. The untapped push -push transformer, however, addsthe voltage drops across its pri-mary since they are in phase. Thus,a signal is induced in the second-ary. Since the speakers are effec-tively in series with the secondarythey will each receive the samesignal.

When out -of -phase signals ap-pear on the amplifier grids, thepush-pull arrangement automati-cally becomes effective. Currentsat opposite ends of the push -pushtransformer primary are opposite in

phase and therefore no signal isinduced in the secondary. The cen-ter tap of the push-pull transformeris now effectively at ground poten-tial. Out -of -phase signals appearacross the push-pull secondary, op-erating the two speakers as before.

Another example of intelligentcost-cutting is, of course, the use ofpiezo-type cartridges (crystal orceramic). Their much higher out-put, as compared to magnetic car-tridges, permits elimination of thestandard preamplifier stage. Con -

4.J

o -.-o

WJ ICONVENTIONAL

STEREOPICKUP

oL. 1-..

LLI 1 -?.0J CC

+ - - +L.

WJ C --C.

PHASE-SHIFTEDSTEREOPICKUP

Fig. 2-Modified push-pull audiooutput circuit shown in Fig. I re-quires cartridge phase reversal ofone channel. Unless a speciallyphased 3 -terminal pickup is used,4 -terminal one must be employed.

sequently, cost is lowered and a po-tential hum stage is removed fromthe circuitry.

Reverberation Circuits

Stereo package manufacturersare obviously not content to sit backand design modified copies of com-ponent equipment circuitry. Re-verberation systems can attest tothis. Motorola, Philco, and Zenithhave already announced incorpora -

Fig. 3-Philco reverberation system adds a controlled amount of echoto the output sound. Permits listener to insert reverberation accordingto his room size, furnishings and taste.

10(5

LI....,.PL,IK

41157

511110

Wag 501.1./.1,011 51.5T5

k

lets taB 9

CIF

II " III

L----

nt

e.

e its

tion of a sound delay system intheir newest stereophonic sets.

The principle is exciting. In aneffort to produce the effect of lis-tening to "live" sound, the acousti-cal properties exhibited in a hall orauditorium are simulated throughan echo -producing system. The de-gree of echo or reverberation canbe adjusted by the user to effectthe most pleasing personal soundreverberation [see ELECTRONICTECHNICIAN, July 1960], thereby"adjusting" sound to the listeningarea. Figs. 3 and 4 illustrate two re-verberation circuits now being used.

Evaluating Packages

Realistic personal appraisal ofstereo package sets is invaluable toboth dealer and non -dealer servicetechnician. The non -dealer techni-cian must familiarize himself withthe capabilities ... and limitationsof new stereo portables and consolesthat he will eventually service. Thedealer technician must, additionally,select merchandise that will fulfillhis sales needs and meet the chal-lenge of competitors. This requiresintelligent evaluation of set perfor-mance.

Evaluating a package set is moredifficult than evaluating a compo-nent unit. Package sets aren't sub-ject to the magnified attention thatcomponents are given in variousconsumer publications. It's the rareindividual that even knows thename of a speaker in a package set,or the amplifier's output wattage.The real test for a package is to lis-ten to it critically. Use appropriateprogram material and try to per-ceive if it delivers solid, clean bassat sufficient volume for your needs.


Fig. 4-Zenith also utilizes a reverberation system. As is the currentpractice with reverberation units, one channel's sound is delayed ap-proximately 33 milliseconds by a mechanical delay line.


Stereo Sales Set -Up For DealersMerchandising Techniques For Selling Stereo Equipment

& Accessories

After basic retail sales principles,selling techniques must be based onthe type of merchandise being of-fered. Thus, retail sales of stereoequipment, especially components,require specialized selling methodsbeyond basic merchandising.

Stereo package equipment gen-erally demands appliance -type sales-manship. Purchasers are usuallyless audio sophisticated than com-ponent purchasers. Additionally,package equipment purchasing isoften influenced by brand name,price and "furniture" appeal. Conse-quently, "packaged"on salesmen are limited to a surfaceknowledge of stereo principals andapplying this knowledge to the unitbeing sold. Standard selling meth-ods are, thus, typically employed,as in appliance, hardware, or de-partment stores.

Component selling, on the otherhand, requires additional salesskills. Prospective buyers are oftenvery much aware of stereo hi-fi ter-minology and applications. Most candetect a salesman not "in -the -know"without difficulty. They've generallybeen influenced by consumer maga-zine evaluations, performance speci-fications in advertising, friends whoalready own a stereo hi-fi system,and previous hi-fi salon shopping.In substance, they may already havean excellent layman's knowledge ofstereo and high fidelity.

This doesn't deny that a largecross-section of component shop-pers are unaware of stereo and hi-fi's many facets, but the salesmanmust be prepared to sell both thetyro and experienced customer. Thelatter customer is usually more dif-ficult to sell since much of his"picked -up" knowledge is misinter-preted by him due to technical limi-

tations. The salesman may, there-fore, have to correct some distortedviewpoints of an individual thatfeels he "knows" the field. This de-mands patience, tact-and knowl-edge.

Sales Demonstrations

Stereo component sales (as wellas package sales) constitutes an"active" selling field, rather than apassive one. Customers want to hearthe equipment they're contemplatingbuying. Thus, the salesman mustdemonstrate his wares.

Ideally, stereo should be demon-strated in the customer's home.

2=2=^PARTS E.

SERVICESHOP

COUNTER

SPEAKERS

STEREO -HI -FI

DEMON-STRATION

AREA

DISPLAY DISPLAY QAREA AREA

Oo,000Fig. 1-Stereo components demonstration areain a small service -sales store. Although spacemay be limited, demonstration areas shouldnot conflict with store traffic.

Since this is impractical, the nextbest way is to have a demonstrationroom. Most companies, however,cannot set up a separate listeningroom in their store. This leaves onlyone sensible demonstration method,that is, if the sales dealer is trulyserious about selling stereo-ademonstration area.

The demonstration place can bea plush area set aside in a section ofthe store, or, if space doesn't permit(and it usually doesn't), a shelf dis-play that partially infringes on theselling space of other items. Cus-tomers should, however, be able toconveniently stand and listen to thesets without being constantly jos-tled by other incoming and outgoingcustomers. Standing and listeningspace must be provided or the dem-onstration equipment set-up will benullified. A typical small -store dem-onstration area is shown in Fig. 1.

Equipment

We hesitate to say nobody willadopt an elaborate demo area, but itis very expensive, and very fewdealers are likely to adopt it. Themajority of dealers, however, cansuccessfully employ a small -storestereo sales set-up. This can beachieved with a one unit demonstra-tion system.

The single system, minimum in-vestment set-up is simple. A medi-um power stereo amplifier/preamp-lifier can be used, with two book-shelf -type speakers, a record chang-er, and a few interchangeable cart-ridges. The -particular makes can beselected from numerous availableunits. Dealers choosing the "mini-mum investment" set-up should becautious about their single compon-ent purchases. The componentsshould be readily available from alocal distributor, have reasonablygood hi-fi performance, and the dis-count should enable the dealer toobtain an adequate sales profit.

Other profits, aside from the saleof components, will naturally ac-crue : accessories, installation, serv-ice, and increased store traffic. Total


INPUTLEVEL

COMPENSATION

oo

INPUTSELECTOR

SWITCH

o

o

PHONO, TAPE OR TUNERSOURCES

LOWLEVELINPUT

HIGHLEVELINPUT

MASTERPRE AMP

EQUALIZERCONTROL

POWERAMPLIFIERS

SPEAKER EFFICIENCY COMPENSATION

-

o

L

o

oo

--

AMPLIFIER GAIN COMPENSATION

GANGED

AMPLIFIER SELECTOR SWITCH

L GANGEDSPEAKER SELECTOR SWITCH

-o

OI0-,D2

/1 O-O 3

j 0--04o O5

U COM

SPE AKERS

Fig. 2-Modest switching panel for A -B listening tests. Sensitivity andefficiency of equipment is compensated so playing level doesn't changewhen switching from one component, or speaker, to another. Since

initial investment need not exceed$400. If the dealer cannot approachthis amount for investment purpos-poses, however, he should never hopeto establish himself beyond the oc-casional sales level.

The big, impressive demonstra-tion panel is, of course, a wonder-ful way to sell stereo. If the dealerreally wants to make the stereo hi-fifield sales a major factor in hisstore, he can do it with a modestversion of a switching panel, asshown in Fig. 2. A small represen-tative number of components will berequired.

He will want to switch a few am-plifiers, speakers, tuners, changersand turntables, and perhaps a tapedeck. Tuner and pickup inputs needcompensating so the level does notchange when switched from one toanother. To the unaware customer,nothing is more obvious thanchange in volume ; he may naturallyconclude that the one soundingloudest is the best for him.

The same procedure is necessaryto compensate for different efficien-cies in loudspeakers. The best placeto do this is ahead of the main am-plifiers. This complicates theswitching somewhat, but makes theoverall result worth it. Set every -

most customers conclude the loudest sound is best, maintaining thesame sound level during a comparison demo permits buyers to makeunprejudiced selections.

thing up so the least efficient loud-speaker, with the least sensitivepickup and tuner, gives adequatevolume with the compensating con-trols all out. Then adjust the con-trols for other units so they all givethe same volume when changes aremade.

Many demonstrations are spoiledby using poor program material. Itcan be poor because it is just poorstereo, because the recording is poorin other respects, or because thetype of music selected doesn't ap-peal to the prospect. Don't assumehis musical tastes are the same asyours. Have on hand a good selec-tion of recordings that give goodstereo at high program quality.

Play what the prospect fancies.And try to give him a cross-section:small intimate presentations, big or-chestra and chorus presentations,pop vocals, etc.

Having acquainted your prospectwith what stereo can sound like andwhat he gets for how much, see whatelse he needs to fulfill his specificrequirements.

Accessories

Don't sneer at accessory sales;they're big money makers. Variousaccessories can be chosen by the

dealer to boost sales profits. But re-gardless of which ones are selectedthey must be prominently displayed.Otherwise, how would your custom-ers know you stock them, or makeimpulse purchases?

Accessories can be roughly di-vided into four areas: componentparts, chemicals, test, and installa-tion.

Component parts consists of re-placement or original parts such asphono cartridges, tape heads, audiotubes, microphones, and phono idlerwheels; tape splicing equipment,tape head demagnitizers and FMantennas ; in other words, service orupgrading aids.

Chemicals, unlike most other ac-cessories, are depleted after a whilethrough use. They are used to cleanrecords, remove record static, cleantape heads, etc. Chemically impreg-nated record cloths are also popular.

Test accessories are varied. Someof the more popular ones are : recordstrobes for indicating speed, tonearm pressure measuring devices,tape strobes, level indicators, andstereo balance meters.

Installation parts are becomingincreasingly popular, especiallysince peg -board displays have been



The greatest beauty of

Thorens famous quality...

you can afford it!

TD -184

MARVELOUS!TD -184. Includes tone armand simple dialing systemthat lets you selectrecords and start turntable.All 4 speeds. Save $20 onturntable, up to $30 ontone arm. Look at TD -184... only $75.00 net.

MATCHLESS!TD -124. All four speeds.Plays any record. Easy -to -use lighted strobe setsexact speed for best musicalreproduction. Completelysilent. Many more exclusivefeatures... only $99.95 net.

No need to hesitate, you can afford Thorensfamous quality. You can have music as it'smeant to be heard. You can relax with Thorensunique one year guarantee. There's a Thorensmodel that fits handily into any budget.

Whether you know a lot or a little abouthigh-fidelity equipment, you'll particularlyenjoy the courteous and knowledgeable way aThorens franchised dealer earns your confidence.Each Thorens dealer is carefully selected forknowledge, ability and integrity. They'll makebuying your Thorens almost as much fun asowning it. Shop around this page for a few ofthe outstanding features and then stop inand see all of them for yourself. 0.5

Guaranteed for one full year. Sold only throughcarefully selected franchised dealers.

SWISS MADE PRODUCTSMUSIC BOXES HI-FI COMPONENTSSPRING -POWERED SHAVERS LIGHTERSNew Hyde Park, N. Y.

MOST ECONOMICAL!TDK-101. You can assemblethis Thorens turntableyourself. The superb qualityof the components makesall your work worthwhile.Look at Thorens TDK-101... only $47.50 net.

For more data, circle 9-110-1 on coupon, p. 78110 ELECTRONIC TECHNICIAN September, 1960

MORE ECONOMICAL!TD -134. The finest 4 -speedmanual turntable you canbuy. Includes tone arm.Elimination of semi-automatic feature saves youanother $15. You can alsosave up to $30 on thetone arm. Look at TD -134... only $59.95 net.

TD -134

MANUFACTURER & PRODUCT

STEREO DIRECTORYACOUSTIC RESEARCH, INC., 24 Thorndike St.,Cambridge 41, Mass.-Spkr AR -1, $185.00.AR -2, $96.00. AR -2A, $122.00. AR -3,$216.00. Spkr-Enc AR -3t, $92.00. AR-3st,$35.00.ACTION SYSTEMS, Meriden, Conn. -Baffles,Record Players, Tuners.ADVANCED ACOUSTICS CORP., 391 LakesideAve., Orange, N.J.-Spkr #440, self -en-closed bi-phonic coupler, $134.50. Modu-laire, self -enclosed, $120.40.ALDSHIR MFG. CO., 111 Lake Ave., Tuckahoe,N.Y.-Needles. Cartridges. Acces, phono.ALL CHANNEL PRODUCTS CORP., 47-39 49thSt., Woodside 77, N.Y.-Acces, FM antenna$19.95, $29.95.ALLIED RADIO CORP. (KNIGHT), 100 N. West-ern Ave., Chicago 80, III. -Tuner KN-125B,FM -AM, $139.95. KN-135B, FM -AM,$84.50. Rcvr KN-300, $169.50. Amp stereoKN-728B, 28 watt, $79.95. KN-740B, 40watt, $99.95. KN-775, 75 watt, $169.50.Spkr KN-2000A, 12" 3 -way with enclosure,$84.50. KN-800A, 12" 3 -way, $44.95. KN-600HC, 12", $64.50. KN-810A, 15", $54.95.KN-850, 12" Deluxe, $79.50. KN-815A, 15"Deluxe, $89.95. Turntable KN-1000, $49.95.Cartridge KN-500, $12.95. KN-500X,$17.95. Tape Rec KN-4300, $249.95.ALONGE PRODUCTS, INC., 163 W. 23 St.,New York 11, N.Y.-Acces, tape splicer800, $29.95.AMERICAN CONCERTONE, INC., 9449 W. Jef-ferson Blvd., Culver City, Calif. -Tape Rec505, $495.00. TR-100 $199.95. 93, $995.00.33, $995.00. Mark VII, $940.00.AMERICAN GELOSO ELECTRONICS, INC., 251Park Ave., South, New York 10, N.Y.-MikeM-60, M-61, $60.00. M-62, M-63, $48.00.M-110, $19.95. M-51, $14.95.AMERICAN MICROPHONE CO., Rockford, III.AMERICAN TELEVISION & RADIO CO. (ATR)300 E. 4th St., St. Paul I, Minn.-Acces, DC -AC Inverters 12U-RHG, $66.34. 12U-RSF,$50.00. 12T-RME, $33.00. Tube Protector#250, $2.63.AMPEX AUDIO CO., 1020 Kifer kd., Sunny-vale, Calif.-Amp/Spkr, unmounted #304,$295.00. #2010 portable, $199.50. StereoPreamp/control ctr #404, $159.50. Tuner,AM -FM stereo, #504, $249.50. #550 StereoAM -FM & preamp, $275.00. Tape Rec #902,unmounted stereo, $349.50. #910, mountedportable, $399.50. #952, unmounted stereo,$499.50. #960, mounted portable, $495.00.#970 stereo monitoring, $595.00.AMPEX MAGNETIC TAPE PRODUCTS, P.O. Box190, Opelika, Ala. -Tape.AMPLIFIER CORP. Of America, 398 Broadway,New York 13, N.Y.-Tape Rec TransMagne-mite 612A,B,C,TD,SD,E, $445.00-$505.00.TransFlyweight 312A,B,C,TD,SD,E,$396.00-$477.00. VU Magnemite 610 AV,BV,CV,TV,DV,EV, $315.00-$425.00. Magne-loop 535B,C,D,E, $315.00-$810.00. Acces,magneraser 200-C, $18.00.

ARGOS PRODUCTS CO., 301 Main St., Genoa,III.-Spkr TSE -1S, $24.95. TSE-2AS,$39.95.ARKAY INTERNATIONAL, INC., 88-06 VanWyck Expwy., Richmond Hill, N.Y.ASTATIC CORP., Conneaut, Ohio -Cartridge13TB ceramic, $7.95. 13TBX ceramic,$11.95. 86TSTB crystal, $8.50. 76TSTBcrystal, $7.95. 9-7B ceramic, $7.25. 9-7BXceramic, $13.25. 11T7B ceramic, $7.95.13AT ceramic, $7.95. 13ATX ceramic,$13.95. Mike 77 dynamic, $82.50. 788 dyna-mic, $78.50. 888 dynamic, $110.00. 988 dyna-mic, $150.00. 333 ceramic, $17.90. 332crystal, $17.90. 335H dynamic, $26.50. 335Ldynamic, $23.50.ATLAS SOUND CORP., 1449 39 St., Brooklyn18, N.Y.-Spkr WT -6, 2 way, $34.50. DC -5, $13.20.AUDIO DEVICES, INC., 444 Madison Ave., NewYork 22, N.Y.-Tape.AUDIO -EMPIRE, Div. DYNA-EMPIRE, Inc. (EM-PIRE) 1075 Stewart Ave., Garden City, N.Y.-Cartridge 88 stereo -mono, $24.50. 108stereo -mono, $34.50. Arm 98 12", $34.50*.98P 16", $44.50*. Turntable 208, $87.50.Needles. *Cartridge not included.AUDIOTEX MFG. CO., Div. G -C TEXTRON INC.,400 S. Wyman St., Rockford, III.-Acces, head-demag, 30-112, $9.95, taperaser, 30-114,$33.00, care kit 30-098, $9.95. Control 30-286, $39.50. Tape.

BECKER ELECTRONICS MFG., 1091 RockawayAve., Valley Stream, L.I., N.Y.-Spkr PM.BELL SOUND Div. THOMPSON RAMO WOOL-DRIDGE, INC., 555 Marion Rd., Columbus 7,Ohio -Tape Rec Record/Playback Tapetransport T-310 2 track mono, $129.95;T-313 2 track stereo, $169.95. T321 StereoPlayback, 2 & 4 track, $159.95. PreampRP320 stereo record playback, $129.95. RP -321, mono record/playback, $75.00. Mike45 -Al, $20.00. Amp 2418, stereo 30 watt,$109.95. 2440, stereo 44 watt, $179.95. 6060,stereo 60 watt, $219.95. Tuner 2421, AM -FM stereo $129.95. 2441, AM -FM stereo,$179.95.BLONDER -TONGUE LABS., 9 Ailing St., Newark2, N.J.BOETSCH BROS. (BIRCH), 115 Cedar St., NewRochelle, N.Y.-Phonos hi-fi stereo SD66,$119.95. SD654, $89.95. SA550, $69.95.SA77, $59.95.BOGEN-PRESTO Div., The Siegler Corp., P.O.Box 500, Paramus, N.J.-Rcvr RP -40, FM -AM, $329.50. SRB40, FM -AM, $269.50.SRB20, FM -AM, $219.50. AMP AP -40, 40watts, $199.50. BP -50, 50 watts, $99.50.DB212, 24 watts, $119.95. DS 265, 130watts, $149.50. Tuner TP-40, FM -AM,$189.50. ST442, FM -AM, $149.50. FM51,FM, $115.00. Preamp STP52, FM -AM,$179.50. Control PR2, $99.50. Turntable &Arm* B61, $59.95. B60, $49.95. B50, $40.40.Arm* PAL, $24.95. Turntable T68AH,

$170.00. TT5, $129.50. TT4, $99.50. TT3,$59.95. *Less cartridge.BOZAK MFG. CO., R. T., Box 1166, Darien,Conn.--Spkr B-304, $620.00.BRITISH INDUSTRIES CORP., 80 Shore Rd., PortWashington, N.Y.-Turntable (GARRARD)Type A, lab series, $69.50. Model 301,transcription, $89.20. Spkr (WHARFE-DALE) achromatic series: #60*, fullrange shelf size, $109.50. #50*, full range40 watt, $94.50. WS/2*, 8" full range 20watt, $89.50. Coax 12, full range 40 watt,$139.50. GARRARD Changers: RC88,$59.50; RC98, $69.50; 210, $49.50; RC121,$42.50; cartridges extra. Arm TPA/12,$19.50. *Enclosure included.

CBS -ELECTRONICS, 100 Endicott St., Danvers,Mass.CHANNEL MASTER CORP., Ellenville, N.Y.-Amp 6600, 2 channel, $99.95. Tuner 6610,FM -AM, $84.95. Turntable 6652, 4 speed,$64.95. 6653, 4 speed, $79.95. Spkr. Min-strel 6630, $29.95. Coaxial (CM -10) 6633,$44.95.CLETRON, INC., 1974 E. 61 St., Cleveland 3,Ohio-Spkr C-33812, 4 matched spkrs &crossover, $98.00. Quartet encl kit, includesC-33812, $158.00. C -18N300, 18" Woofer,$180.00. C12RW, 12" Woofer, $59.00. C-12NR, 12" wide range, $33.50. C-8MFR,8" midrange, $13.20. C-12PC, 12" coaxtweeter, $53.50.CLEVITE ELECTRONIC COMPONENTS, 3405Perkins Ave., Cleveland 14, Ohio-Acces,headphones, crystal stereophonic, BA -220,$44.95. BA -206B, $39.25. BA -200B, $24.50.CLEVITE-WALCO, 60 Franklin St., East Orange,N.J.-Needles.COMPONENTS CORP., Denville, N.J.-Turn-table Mark I, single speed, $44.50. MarkII, 33/45 rpm, $54.50. TT, Kit, $29.50. Armkit AS -auto set, $9.50.CONTINENTAL MFG. INC., 1612 California St.,Omaha 2, Nebr.-Spkr CS -14B, $30.69.Multiplex TN66,* $112.80. TN -77, with 5watt amp, $131.53. TN -88 with 15 wattamp, $152.33. *Without amp.CROWN INTERNATIONAL, Box 261, Elkhart,Ind. -Tape Rec 714C, $730.00. 824, $1,-195.00. Amp A3030, $195.00.

DERO ELECTRONICS, 10 Woods Ave., Roose-velt, L.I., N.Y.-Adapter phone jack to pinplug PHPJ, $.95. PHJP, $1.25. Spkr TST-25, extension, $12.95.DEWALD RADIO, Div. of UNITED SCIENTIFICLABS INC., 35-15 37 Ave., Long Island City 1,N.Y.-Tuner N -803B, AM -FM Mono, $77.95.N -1000B, AM -FM stereo, $99.95. N -804B,FM, $74.95. Amp N -1200B, stereo 30 watts,$99.95. N -2200B, stereo 50 watts, $139.95.N -5000B, mono 15 watts, $52.95.DUKANE CORP., St. Charles, III.DUOTONE CO., Locust St., Keyport, N.J.-Nee-dles. Tape. Cartridge GP73, stereo turn -


over, $14.50. GP73SD, $24.50. GPS-71-1S,$20.00. GPS-71-1D, $31.25. Arm GP2-3,with cartridge, $14.50. Mike "Lipstyk"MIC39-1, $20.00. Acces 45 RPM Adapter, 5to a pkg 24 pkgs to a card, $6.00. Pocketneedle inspection microscope, 6 to a card,$30.00. Record Brush, 12 pkgs, $6.00.DYNACO INC., 3912 Powehon Ave., Phila-delphia 4, Pa. -Control DSC-1, kit $12.95,wired $18.95. Amp Stereo 70, kit $99.95,wired $129.95. Arm TA12, $49.95 includingStereodyne II cartridge. Cartridge Stere-dyne II, $29.95. Mike #50, $49.95. #53,$59.95. Preamp Pas -2, kit $59.95, wired$99.95. Tuner "Dynatuner" FM, kit $79.95,wired $119.95.

ELECTRON ENTERPRISES, 6917 Stanley Ave.,Berwyn, 111. -Amp #60, 20 watt 4 speedstereophono, $159.95. Changer #65, 4speed 4 spkr portableestereo, $99.95. #69,2 speed 45 portable mono, $49.95.ELECTRONIC APPLICATIONS, INC., 194 Rich-mond Hill Ave., Stamford, Conn. -Mike AKGD 11N, dynamic cardioid, $34.95. AKG D19B, dynamic broad -band, $68.00. AKG D19 BK/Hi, $74.50. AKG D 88/200 dynamicstereo, $72.00 AKG D 88/Hi/Z, $77.50Tape Rec III B, Nagra, $1,045.00.ELECTRONIC DEVELOPMENT ASSOC., 126 E.

46 St., New York 17, N. Y.ELECTRONIC INSTRUMENT CO., (EICO), 33-00Northern Blvd., Long Island City 1, N.Y.-Amp* HF-81**, wired $109.95, kit $69.95.AF -4**, wired $64.95, kit $38.95. HF-86,wired $74.95, kit $43.95. HF-87, wired$114.95, kit $74.95. HF-89, wired $139.50,kit $99.50. Changer 1007S $49.75. 1007D$59.75 Preamp* HF-85, wired $64.95, kit$39.95. Spkr*** HFS-1, wired $47.95, kit$39.95 HFS-2, $139.95. HFS-3, wired$99.50, kit $87.95. HFS-4, wired $112.50,kit $98.50. HFS-5, wired $69.50, kit $59.50.Tuner HFT-90, FM, wired $65.95, kit$39.95. HFT-94, AM, wired $65.95, kit$39.95. HFT-92, AM -FM, wired $94.95, kit$59.95. ST -96, AM -FM stereo, wired$129.95, kit $89.95. *2 -channel. **Preampincluded. ***Enclosure included. Spkrprices cover Mah/Wal finish.ELECTRO -SONIC LABS., 35-54 36 St., LongIsland City 6, N.Y.-Arm* S1000, $34.95.5310, $57.00. Cartridge C99, $49.95. C100,$100.00 Mike MDS 1, electrodynamic supercardioid, $85.00.*ELECTRO -VOICE INC., Buchanan. Mich.-SpkrSP8B*, $29.50, SP12*, $66.00, SP15*,$89.00. 12TRXB**, $66.00. 15TRX**,$149.00. 12BW***, $35.00. 15WK***,$89.00. 30W***, $185.00. 644, $110.00. Car-tridges (ceramic) : 31MD5, $24.00. 31D-5,$22.50. * Coaxial. ** 3 -way. *** Low freq.

FAIRCHILD RECORDING EQUIPMENT CORP.,10-40 45th Ave., Long Island City 1, N.Y.-Arm SA -12, 12" stereo, $39.95. SA -16, 16"stereo, $60.00. Cartridge SM-1, compatiblestereo, $34.95. 225-A, mono microgroove,$37.50. 225B, mono 78s, $37.50. 230 Micro7, mono microgroove, $42.50. Turntable412-1A, 1 speed, $87.50. 440, 2 speed, $69.95.FEDERATED INDUSTRIES INC. (CRESCENT),4477 N. Elston Ave., Chicago 30, III.-Spkr200-1*, 2 -way 25 watt, $119.95. FA3012,12" 30 watt, $18.50. FÁ1512, 12" 15 watt,$15.50. *Enclosure included.FEN -TONE CORP., 106 5 Ave., New York 11,N.Y.-Tape Rec Mark IV, 3 speed, $89.50.

Mark V, 4 speed $129.50. Mark VI, Truvoxstereo, $149.50. Amp Mark VI Truvox,with preamp, $129.50. Mike Reslo Celeste,ribbon, $39.95. Reslo Symphony, ribbon,$39.95. Cartridge Stereomaster, turnoverphono, $9.95.FERRO DYNAMICS CORP., Gregg St. & Rte.#17, Lodi, N.J.-Tape.FIDELITONE, INC., 6415 N. Ravenswood Ave.,Chicago 26, III.-(PYRAMID POINT)Needles.FISHER RADIO CORP., 21-21 44th Dr., LongIsland City 1, N.Y.-Rcvr TA 800, stereo$429.50. TA600, stereo $369.50. Tuner FM100, $169.50. FM 50, $129.50. 100R, AM-FM, $199.50. 202R, AM -FM, $299.50. 100-T*, AM -FM, $249.50. 202-T*, AM -FM,$349.50. Amp X-100*, stereo, $159.50. X-202, stereo, $229.50. SA -100, stereo, 50 wattbasic, $119.50. SA -300, stereo 60 wattbasic, $179.50. 30A*, mono, $59.50 PreampPR -6, mono, $12.95. PR -66, stereo, $29.95.Adaptor MPX-20, $49.50. Control RK1, re-mote, $17.95. Spkr XP1, $129.50. XP -2,$84.50. WS -1, $49.50 per pr. *Includes pre -amp -control section.FOURJAY INDUSTRIES, 2801 Ontario Ave.,Dayton 14, Ohio-Spkr-Enc 40 differentmodels, made of fiberglass, $1.75 to $22.50.

GENERAL ELECTRIC CO., Audio Products Sec-tion, 2200 N. 22nd St., Decatur, Ill.GENERAL KINETICS INC., 2611 Shirlington Rd.,Springfield, Va. -Custom tape recorders.GLASER-STEERS INC., 155 Oraton St., Newark4, N.J.-Changer GS77, $59.50. GS400,$47.50.

GOTHAM AUDIO CORP., 2 West 46 St., NewYork 36, N.Y.-Cartridge DST, Neumanndouble dynamic stereo, $69.00.Neumann single unit stereo, $815.00. Ac-cess, stereo headphone DT -48, Beyer dy-namic $79.50. DT 508s, Beyer dynamic,$27.50.

GRANCO PRODUCTS, INC., 83-30 Kew Gar-dens Rd., Kew Gardens, N.Y.-Tuner T300,FM, $21.95.

HARMAN-KARDON, INC., 520 Main St., West.bury, L.I., N.Y.-Amp Citation II, basicpower, 2 channel 60 watts per channelstereo, wired $229.95, kit $159.95. CitationV, basic 2 channel 40 watts per channelstereo, wired $179.95, kit $119.95. A10*$49.95. A2205, $79.95. A230* $109.95.A260*, $199.95. Preamp Citation I, con-trol center, wired $249.95, kit $159.95. Ci-tation IV, control center, wired $189.95,kit $119.95. Tuner Citation III, FM, wired$229.95, kit $149.95. F10, FM, $69.95. T220,stereo AM -FM, $99.95. T230 stereo AM -FM, $119.95. ST360A, stereo AM -FM,$199.95. Rcvr TA224, stereo AM -FM$199.95. TA 260, stereo AM -FM, $299.95.*Includes preamp. East Coast prices.HARTLEY PRODUCTS CO., 521 E. 162 St., NewYork 51, N.Y.-Spkr #220, $135.00 #XP,$75.00. With enclosure: Holton Jr*,$195.00. Harp** $190.00 Capri***,$120.00 *With #220 spkr. **With #XPspkr. ***With #320 spkr.HEATH CO., Benton Harbor, Mich. -Kits AmpAA -30, 14/14 watt, $45.95. AA -40, 35/35watt, $79.95. AA -50*, 25/25 watt, $79.95.SA -2* 14/14 watt, $54.95. Changer RP -3series, to $73.90. Multiplex MX -1, $31.95.Preamp AA -20, stereo, $34.95. SP -2A,stereo $56.95. Tuner BC -1A, AM, $29.95.FM3-A, $29.95. AJ-10, AM -FM, $59.95.

Spkr SS -2, $39.95. HH-1, $299.95. TapeRec TR-1E, mono rec/4 track playback,$169.95. TR-1AQ, 4 track mono & stereorecord & playback, $149.95. *With preamp,also wired.HI -PAR PRODUCTS CO., Fitchburg, Mass.-Acces, FM Antennas.

JENSEN INDUSTRIES, 7333 W. Harrison St.,Forest Park, I11. -Needles.JENSEN MFG. CO., 6601 S. Laramie Ave.,Chicago 38, III.-Spkr TF-3, 3 way book-shelf, $79.50. TR-30, 3 way, $159.50. GS -3,3 piece complete stereo, $229.50. TR-10, 3way, $119.50. GS -2, 3 piece complete ste-reo, $169.50. DF -1, 2 way, $69.50. CN-100,3 way, $159.50. SS -100, 3 way, $179.95. SS -200, 4 way, $439.50.JERROLD ELECTRONICS CORP., 15th & LehighAve., Philadelphia 32, Pa.-Preamp DSA-207, mastmounted, $47.95. Amp HSA-43, 3 set coupler, $17.95. HSA-46, TV -FMamp/preamp, $33.30.

KARG LABS, 30 Meadow St., South Norwalk,Conn. -Tuner CT -3 basic FM, $99.50. CT -2Stereo FM, $139.50. Adapter, MX -1 $99.50.KIERULFF SOUND CORP. (CAPKIT), 820 W.Olympic Blvd., Los Angeles 15, Calif.-PhonoCK-643, transistor battery operated 3speed, $44.95.KIMBERLEY INTERNATIONAL LTD., 346 W. 44St., New York 36, N.Y.-Tape Rec UherUniversal, $299.95. Stereo Record, $399.50.Stereo lc, $279.95.KINEMATIX, INC., 1616 N. Domen Ave., Chi-cago 47, III. -Converter "Skylark", FM,$89.95. Acces, stereo balance meter SB-1,$14.95. CM -2, $24.95.KLIPSCH & ASSOCIATES, P.O. Box 96, Hope,Ark.-Spkr Corner horn system with 3 waydrive system: K -B -M2, $792.00. K-BML,$734.00. K-BMR, $651.00. K-CM2S, $693.00.K-CMR $617.00. K-CFR, $538.00. SMR15,$314.00. SM212B, $205.00. SMR12B,$165.00. SD12B, $99.00. Enclosure with 3 -

way drive system: H -M2-12, $214.00. H -M2 -12B, $110.00. HD12, $184.00. CWM215,$393.00. CWD12, $242.00.

LAFAYETTE RADIO ELECTRONICS CORP., 165-08 Liberty Ave., Jamaica 33, N.Y.-Amp KT -250A*, 50 watt kit, $74.50. LA -250*, 50watt wired, $99.50. LA -235*, 35 watt,$69.50. KT -550, 100 watt kit, $129.50.LA550, 100 watt wired, $179.50. ArmPK-448, cartridge included, $32.50. Mikedynamic, $6.95-$15.95. Crystal, $2.95-$5.75.Preamp/Control KT -600A, kit, $79.50.LA -600A, wired, $134.50. Tape Rec RK-103,2 speed 3%, 71/2, $99.50. Tuner KT -500A,FM -AM kit, $74.50. LT -50A, FM -AMwired, $124.50. KT -650, FM kit, $54.50.* Preamp included.LANSING SOUND, INC., JAMES B., 3249 Ca-sitas Ave., Los Angeles 39, Calif.-SpkrD46S5*, $249.00. D45202*, $868.20. D4-5205*, $1,183.20. D44000, $2,070.00. D4-4000BK, $1,830.00. *Enclosure included.L.E.E. INC., 625 New York Ave., N.W., Wash-ington 1, D.C.-Spkr Catenoid*, $495.00.Fantasia*, $129.50. Trio*, $119.50. *En-closure included.LESA OF AMERICA, 11 W. 42 St., New York36, N.Y.-Changer CD2/21, $44.50. Turn-table 4V3/11, $23.25. Cartridge "E", turn-over crystal -mono 78LP, $9.95. "S", crys-tal stereo LP, $16.50. Needles.



.a v

L,.NEWS LETTER

AUDAX appoints Syd Jurin Co. as SouthernCalifornia sales rep.

BOGEN-PRESTO appoints the F. P. YarussiCo. sales rep for W. Va. and West Pa.

BELL SOUND announces new stereo compo-nent line will be distributed through two-step distribution channels.

LAFAYETTE introduces the "Trihelix" 10"3-way speaker @ $32.50. Response rating is30-12,000 cps ± 3 db, average power 20watts.

MINNESOTA MINING has purchased REVERECAMERA, and will use its facilities toproduce tape players capable of using the3M cartridge.

GENERAL ELECTRIC announces productionof a transistorized home intercom system,retailing at $79.95 per pair. Voice sig-nals are carried over existing house wir-ing, eliminating need for wiring betweenunits.

H. H. SCOTT offers to replace any ofthe original London-Scott 1000 stereocartridges with their new, ruggedized ver-sion of the unit. The new cartridge main-tains identical performance specs of theoriginal.

ARMOUR's tape patent used by 3M wasruled invalid by the U.S. Court of Ap-peals, and judged not infringed by C. K.WILLIAMS and TECHNICAL TAPE. The patentcovers the production of magnetic ironoxide used in recording tape.

PACOTRONICS, INC., which has become apublicly held company, is the new corpo-rate name of Paco Electronics, as well asPrecision Apparatus and Pace ElectricalInstruments. They will operate as subsidi-aries under their own names. There is nomanagement change.

ELECTRONIC INDUSTRIES ASSOCIATION isreported to have scrapped a proposed planto publicize stereo to consumers. Though amajority of the EIA committee favored theidea, a favorable majority of 75% was notobtained. The plan was contingent on re-ceiving 75% approval.

ROBINS INDUSTRIES introduces new pack-aging for the "Gibson Girl" Jr. TapeSplicer, Model No. TS4A-JR., followingtheir orange and black motif. Also pub-lishes 16-page phono-recorder drive ref-erence, which aids replacement drive se-lection for nearly 95% of wheels andbelts. It is free with parts deal DD-10RP,or 50¢ separately.

from E/COI°.. a completely new

CITIZENS BAND TRANSCEIVER

Model 760: 117 VACKit $59.95 wired $89.95

Model 761: 117 VAC & 6 VDCModel 762: 117 VAC & 12 VDC

incl. mounting bracket: Kit $69.95, Wired $99.95

'EICO premounts, prewires, pretunes, and seals the ENTIRE transmitteroscillator circuit to conform with FCC regulations (Section 19.71 sub-division d). EICO thus gives you the transceiver in kit form that you canbuild and put on the air without the supervision of a Commercial Radio»Telephone Licensee!

Highly sensitive, selective SUPERHET (not regenerative) receiver with 5%dual function tubes and RF stage. Continuous tuning over all 23 bands.Exclusive Super -Hush) noise limiter. AVC:3" x 5" PM speaker. Detachableceramic mike. 5 -Watt crystal -controlled transmitter. Variable "pi" networkmatches most popular antennas. 12 -position Posi-Lock® mounting bracket.7 tubes and 1 crystal (extra xtals available). Covers up to 20 miles.License available to any citizen over 18-no exams or special skillsrequired, application form supplied free. Antennas optional.

YOU PROFIT WITH EICOEverything in top-qualityTEST EQUIPMENT for Shopand Field-at savings of 50%.

AK,

V

111:--a

,y

COLOR & Mono DC-5MCLab & TV 5, Oscilloscope #460Kit $79.95, Wired $129.505" Push -Pull Oscilloscope #42.9Kit $44,95, Wired $79.95

Peak -to -Peak VTVM #232Klt $29.95, Wired $49.95Vacuum Tube Voltmeter #221Kit $25.95, Wired $39.95

More typical EICO values: Signal Gen-erators from $19.95, Tube Testersfrom $34.95, Sweep Generators from$34.95 Power Supplies from $19.95,110M$ from $12.90.

Everything in CUSTOM HI -F/:finest quality at 7/3 the cost.

FM Tuner HFT90Kit $39.95, Wired $65.95Cover $3.95. Includes FET.AM Tuner HFT94Kit $39.95, Wired $65.95Includes Metal Cover and FET,FM/AM Tuner HFT92Kit $59.95, Wired $94.95Includes Metal Cover and FET.

Stereo Dual Amplifier-Preamp HF91Kit $69.95, Wired $109.95Includes Metal Cover.Stereo Dual Amplifier AF4Kit $38.95, Wired $64.95Includes Metal Cover.

Write for free catalog ET 9 andname of nearest distributor.

Most EICO distributors offer budget terms.

3300 N. Blvd., L.I.C. 1. N. YiAdd 5% in the West

ELECTRONIC TECHNICIAN September, 1960For more data, circle 9-113-1 on coupon, p. 78

113


LING-ALTEC ELECTRONICS, Anaheim, Calif.

LOWELL MFG. CO., 3030 Laclede Station Rd.,St. Louis 17, Mo.-Electric Lamp Post withspkr enclosed PBA-8, $32.30.

MADISON FIELDING by CROSBY, 135 EileenWay, Syosset, N.Y.-Rcvr #440, $350.00.#650, $219.95. Tuner #630, FM, $84.95.#380, AM -FM stereo, $160.00. Amp #360*,2 channel, $180.00. Multiplex Adapter MX -100, $49.95. Spkr #660**, $29.95. Acces#30 transistor single channel preamp,$11.25. Wood cabinet #350, $20.00. #450,$30.00. Metal enclosure, $11.95. *Preampsincluded. **Enclosure included.MAGNECORD SALES DEPT. MIDWESTERN IN-STRUMENTS, P.O. Box 7186, Tulsa 18, Okla. ---Tape Rec #728*, $809.00. #101-1, $479.95.Stereo rec M90-BAC*, $2,255.00. P75-BAC*, $1,305.00. Spkr-amp combination#110, $129.95. *With preamp.MARANTZ CO., 25-14 Broadway, Long Is-land City 6, N.Y.-Amp #8, 2 channel,$237.00. Preamp/contr #7, $249.00. Pricesare East of Rockies. West slightly higher.McINTOSH LABS., 2 Chambers St., Bingham-ton, N.Y.MINNESOTA MINING & MFG. CO., MagneticProducts Div., (SCOTCH BRAND), 900 BushAve., St. Paul 6, Minn. -Tape.MOVIC COMPANY, 12432 Santa MonicaBlvd., Los Angeles 25, Calif. -Tape Rec A-2,$645.00. A-214, $695.00. A-2-15, $710.00.A-214-15, $760.00.MP ENGINEERING CO., Fairfield Conn.-Phono PB-88, stereo, $188.00. J602*,$695.00. *Enclosures in-cluded.

NESHAMINY ELECTRONIC CORP. (ZANSZEN),382 Easton Rd., Neshaminy, Pa.-Spkr Z-400*, shelf, $149.50. Z-300*, full range,$199.75. #130*, mid range & highs,$188.00; #65*, mid range & highs, $91.50.#350 Driver, $44.50. #250 Driver, $69.75.*Enclosure included.NEWCOMB AUDIO PRODUCTS CO., 6824 Lex-ington Ave., Hollywood 38, Calif. -Tape RecSM-310, 1/2 track stereo -mono, $499.50.SM-310-4, 1/4 track stereo -mono, $499.50.NORTH AMERICAN PHILIPS CO. (NORELCO),230 Duffy Ave., Hicksville, N.Y.-CartridgeAG3400, magneto -dynamic, $29.95.Changer AG1024, 4 speed, $39.50. Spkr T-7Series, 5" to 12", $6.60-$59.50. Tape RecContinental 400, 4 track 3 speed stereo -record, $399.50. Mike, stereo dynamic,$39.50.NORTRONICS CO., 1015 S. 6th St., Minneapolis4, Minn. -Amp RA -100, mono. Preamp PI -100, mono. Tape.

OXFORD COMPONENTS, 556 W. Monroe St.,Chicago 6, III. -Horn Tweeter CH26E16,$21.00 and others.

PACO ELECTRONICS CO., 70-31 84 St., Glen-dale 27, N.Y.--Amp SA -40, 2 -channel. Pre -amp included, wired $129.95, kit $79.95.Rcvr ST -45, AM -FM stereo, wired $134.95,kit $84.95, semi kit $99.95. ST -35, FM,wired $89.95, kit $59.95, semi kit $69.95.Spkr L-1*, semi kit, $24.95. L-2*, semi kit,$69.95. *Enclosure included.PENTRON CORP., 777 S. Tripp Ave., Chicago24, III.

PERMADYNE DIV., MELODY MASTER MFG.CO., 2149 W. Roscoe St., Chicago 18, III.-Acces Headsets, extended range, HS -1,$36.00.

PERMOFLUX PRODUCTS CO., 4101 San Fer-nando Rd., Glendale 4, Calif.-Acces, head-phone DHS-17, monaural, $52.50. B-DHS-25M, binaural, $52.50. Amp RSD-10,$175.00. Spkr Arpeggio, stereo, $55.00.Largo, stereo, $89.50.PERMO INC., 6415 Ravenswood Ave., Chicago26, III.

PFANSTIEHL CHEMICAL CORP., 104 Lake ViewAve., Waukegan, III. -NeedlesPHILCO CORP., C & Westmoreland, Philadel-phia 34, Pa. -Model 1720R reverbaphonicsound system.PICKERING & CO., Sunnyside Blvd., Plain-view, L.I., N.Y.-Arm #198, with integrated380A cartridge, $54.00. Cartridge Stereo"90"*, $16.50. MkIIA*, $26.40. MkIIC*,$24.00. 380A*, $34.50. 380C*, $29.85. 381A*,$48.00. 381E*, $60.00. Needles. Turntable800 Gyropoise Stereotable, 331A singlespeed, $66.00. Acces 800 CB base forStereotable, $15.00. *Stereo magnetic.PILOT RADIO CORP., 37-06 36th St., LongIsland City 1, N.Y.-Amp #260*, 40 watt/channel, $139.50. #264*, 30 watt/channel,$179.50. #240*, 15 watt/channel, $134.50.#248*, 30 watt/channel, $249.50. Preamp216A*, $199.50. Rcvr #602, 15 watt/chan-nel, $249.50. #654, 22 watt/channel, $299.-50. Spkr PSV1**, $139.50. PSV2**, $69.50.PSV3**, $64.50. Tuner #480, FM/AM,$159.50, #590, FM/AM & dual preamp,$239.50. #690A, FM/AM & dual preamp,$219.50. *2 -channel. **Bookshelf.PRECISION ELECTRONICS INC. (GROMMES),9101 King St., Franklin Park, 111. -Amp 24LJ*,Dual 15 watt stereo, $89.50. 36PG*, Dual20 watt, $189.50. 50PGA*, Dual 25 watt,$219.95. LJ8, 15 watt monaural, $69.50.240A*, Dual 25/watt basic, $109.95. Tuner102GTB*, AM -FM, $129.95. 101GTB*, FM,$79.95. Preamp 209*, $159.95. 20LJ*, stereodual 10/watt, $79.95. *Does not includecover.PRO-TEX REEL BAND CO., 2108 Payne Ave.,Cleveland 14, Ohio-Acces, tape reels &fasteners.

QUAM-NICHOLS CO., 234 E. Marquette Rd.,Chicago 41, III.-Spkr 8A10X, $20.00.12A6CO3 $34.50. 8A4CO3 $22.95. 3A15T,$5.75. 5A15T, $6.50. 12A1 OX, $26.00. 12A1-OL, woofer, $26.00. 15A1000, $52.50. 10A1 -OX, $24.00. 15A1OL, woofer, $35.00. Acces,crossover network for 3A15T-5A15T,#CO2-50, $2.00.

RECOTON CORP., 52-35 Barnett Ave., LongIsland City 4, N.Y.REEVES SOUNDCRAFT CORP., Green PastureRd., Danbury, Conn.REGENCY DIV., IDEA, INC., 7900 PendletonPike, Indianapolis 26, Ind.REK-O-KUT CO., 38-19 108 St., Corona 68,N.Y.-Turntable K-33, kit, single speed33-1/3, $39.95. K -33H, kit, single speed33-1/3, $49.95. L-34, 2 speed, 33-1/3/45,$59.95. L-37, 2 speed, 33-1/3/78, $59.95.N -33H, single speed, 33-1/3, $69.95. L -34H,2 speed, 33/45, $79.95. L -37H, 2 speed,33/78, $79.95. B-12, 3 speed, 33/45/78,$84.95. B-12GH, 3 speed, 33/45/78, $99.95.B -12H, 3 speed, 33/45/78, $139.95. ArmS-120*, 12", $24.95. S-160, 16", $27.95.S-220, 12", $29.95. S-260, 16", $34.95.

AUDAX DIV.-Spkr CA -60, bookshelf,$59.95. CA -60P, $49.95. CA -80, $99.95. CA -100, $139.95. *Does not include cartridge.REITER CO., F., 3340 Bonnie Hill Dr., Holly-wood 28, Calif.-Acces Skila 1/4" tape splic-er, $69.75.ROBINS INDUSTRIES CORP., 36-27 Prince St.,Flushing 54, N.Y.-Acces, M/M R/P heads,5 models 1/2 track mono, $14.00-$16.00. 5models 1/2 track stereo, $27.00-$31.00. 2models 1/4 track stereo, $30.00. M/Merase heads, 3 models 1/2 track mono,$11.00. 2 models 1/2 track stereo, $15.00.9QE3, 1/4 track stereo, $14.00. Replace-ment parts for phono & tape recorderdrives, $.25-$6.30. Splicers, recording tape,TS4A Series, $6.50-$11.50. TS Series,$55.00. Bulk tape eraser ME99, $33.00.Head Demagnetizer HD -6, $10.00.ROCKBAR CORP., 650 Halstead Ave., Mama-roneck, N.Y. Changer (COLLARO) TSC-640, $38.50. TSC740, $42.50. TC99, $59.50.Turntable ATR200, $49.50. Spkr (GOOD -

MANS) Audiom 652, 12", $69.50. Audiom755, 15", $78.00. Axiette 11-8, 8", $27.00.Midax H-750, mid range, $58.50. Stereo-sfere, 30 watt, $79.50.ROCKFORD SPECIAL FURNITURE CO., 1803Belle Plaine, Chicago 13, III.-Spkr-Enc#108, for 8" spkr & tweeter, $26.95. #112,for 12", $42.95. #101, for 12" or 15", $54.50.RYE SOUND CORP., 145 Elm St., Mamaroneck,N.Y.

SARGENT-RAYMENT CO., 4926 E. 12 St., Oak-land 1, Calif. -Amp SR5100*, 50 watts/channel, $183.60. SR540*, 20 watts/chan-nel, $106.60. SR2051*, 50 watts/channel,$263.70. SR2040*, 20 watts/channel,$199.50. Rcvr SR8000, $249.40. SR7000,$199.40. SR1000b, $184.50. Tuners SR1020,FM, $97.50. *2 -channel.SAXTON PRODUCTS, INC., 4320 Park Ave.,New York 57, N.Y.-Acces, FM antennas,#1124, $1.69. Tape storage case, $.89.SCOTT INC., H. H., 111 Powder Mill Rd., May-nard, Mass. -Amp #272*, 88 watt, $269.95.#299B*, 50 watt, $209.95. #222B*, 30 watt,$144.95. #290 stereo power, 100 watts,$239.95. Preamp/control #122, stereo dy-naural, $285.00. Tuner #314, FM, $114.95.#330-D, FM -AM, stereo, $209.95. #310-D,FM, $184.95. Arm L/S1000, with inte-grated cartridge, $87.95. Turntable 710A,3 speed, $129.95. *Stereo with preamp.SCOTT INSTRUMENT LABS, 17 E 48th St., NewYork, N.Y.-Acces, tape strobe Model A,checks 71/z-15 & 30 ips, $22.50. Model B,3%-71/2-15 ips, $22.50. Model C, 1%-371/2-15 ips, $24.50.SETCHELL-CARLSON INC., New Brighton, St.Paul 12, Minn.-Spkr RP91-B4, mono -ste-reo, $149.00. 4814-B*, extension, $78.00.Amp RP90-A**, 2 -channel, $69.95. *En-closure included. **Preamp included.SHELL ELECTRONICS MFG. CORP., 112 StateSt., Westbury, N.Y.SHERWOOD ELECTRONIC LABS., 4300 N. Cali-fornia Ave., Chicago 18, III. -Amp S-5000*,2 -channel, $189.50. S-4400*, 2 -channel,$159.50. Tuner S-2200, FM/AM/MX,$179.50. S -3000ííI, FM/MX, $110.50. *Pre-amplifier included.SHURE BROTHERS, INC., 222 Hartrey Ave.,Evanston, III. -Arm M212 & M216, cartridgeincluded, $89.50. M232*, $29.95. M2365,$31.95. Cartridge M3D**, $45.00. M3LS**,$75.00. M7D**, $24.00. M8D, $16.50. Mike#333, ribbon, $150.00. #300, ribbon, $90.00.


#330, ribbon, $72.00. #315, ribbon, $53.70.#525, dynamic, $120.00. #530, dynamic,$66.00. #535, dynamic, $43.50. #545, dy-namic, $51.00. #55S, dynamic, $49.80.#556S, dynamic, $81.00. M-60, stereo linepreamp equalizer, $19.95. *Does not in-clude cartridge. **Stereo magnetic.SMOLIN LABS., Woodbrook Drive, Springdale,Conn.SONOTONE CORP., Elmsford, N.Y.-Cartridge9T Series*, $16.50-$19.50. 8T Series*,$14.50-$16.50. 10T Series*, $6.45-$13.45.12T Series, stereo crystal turnunder, $6.45.Arm, Ti Series, $7.45. Mike CMT-10,matched pair, $36.75 per pair. CMT-11,matched pair, $36.75 per pair. Spkr T-64,$9.00. WR-8, $12.00. CA12A, $27.50. Wi2,$16.00. * Stereo ceramic turnunder.STEPHENS TRUSONIC INC., 8538 Warner Dr.,Culver City, Calif.-Spkr 80FR, $33.50. 80M,$33.50. 80CX, $53.50. 120FR, $60.00. 120W,$60.00. 120CX, $99.50. 150FR, $87.00. 150W,$87.00. 150CX, $129.50. 5KT, $49.50. RT-1,$24.50. E2*, $275.00. Stereodot*, $139.50.* Enclosure included.STROMBERG-CARLSON, 1400 N. Goodman St.,Rochester 3, N.Y.-Amp ASR -880*, 64 watt,$199.95. ASR -433*, 24 watt, $129.95. ASP -422*, 40 watt, $99.95. ASR -333*, 24 watt,$99.95. Arm RA -498, cartridge not included,$24.95. Spkr RF-478**, $39.95. RF-487**,$74.95. RF-484** $124.95. RS -406***,$119.95. RS -405***, $54.95. RS -424, $199.95.Tuner AM -441, $49.95. FM -443, $79.95.SR -445, AM -FM stereo, $129.95. TurntablePR -500, 4 -speed, $69.95. *2 -channel. **2 -way coaxial. ***3 -way with crossover net-work. All prices are Zone 1.SUPERSCOPE, INC., (SONY), 8150 VinelandAve., Sun Valley, Calif. -Tape Rec CS300,2 & 4 track stereo, $399.50. DK300, 2 & 4track stereo, $349.50. 262SL, 4 track mono,$199.50. Mike CR -4, wireless, $250.00.F -3B, $25.00. C -37A, $295.00. FP -2, $35.00.F $15.00.SWITCHCRAFT, INC., 5555 N. Elston Ave., Chi-cago 30, III.-Acces Audio Mixer #310*, forPentron, RCA, Wilcox -Gay, $7.95. #313*,for Revere & Wollensak, $8.95. #326*, forWebcor, $9.95. Audio Mixer 306TR, tran-sistorized stereo -mono 2 or 4 input, $37.50.#301TR, transistorized mono 4 input,$30.00. Amp 501 Mix -Amp, transistorized,$20.00. * "Mini -Mix" 2 -input audio mixerfor tape recorders.TANDBERG OF AMERICA, 8 Third Ave., Pel-ham, N.Y.TANNOY (America) Ltd., P. O. Box 177, EastNorwich, L.I., N.Y.-Spkr, 15" monitor,$179.00. 12" monitor, $138.00. 10" monitor,$112.75. 15" woofer, $123.75. 12" woofer,$78.75. HF tweeter, $86.00. 12" direct radia-tor, $79.00. Spkr-enc Belvedere, for 12",$65.00. Belvedere Sr., for 12" & 15", $85.00.TELECTROSONIC CORP., 35-18 37th St., LongIsland City 1, N.Y.-Tape Rec MR111*,$89.95. SA121*, $129.95. MR121*, $109.95.MR511, 2 speed 1%-3%, $129.95. SR441**$239.95. SS461**, $349.95. MR241**, $179.-95. 900 Series**, $89.95-$139.00. SpkrSP001-1, enclosure included, $44.95. *2

speed, 3%-7%. **3 speed 1%-3%-7171.TETRAD CORP., 62 St. Marys Ave., Yonkers 2,N.Y.THORENS CO., Thorens Ave., New Hyde Park,N.Y.-Turntables TD124, $99.95. TD -184*,$75.00. TDX-101, kit, $47.50. TD -134,

$59.95. Changer CD43NS, direct drive,$79.95. *Arm included.

Sonotone's 1960census over

(yes, 10 million)

cartridgesusé.!nowin

Only a few years ago, Sonotone invented the ceramic cartridge...and hasbeen setting sales records ever since. And no wonder! Over the years,Sonotone has developed its fine cartridge line to the point where today it'sthe standard of the industry. Models available for virtually every type ofphonograph ...used as original equipment by over 70 manufacturers. Infact, Sonotone has already sold over 10.000.000 cartridges. Your customers

will hear the difference... with Sonotone ceramic or new crystal cartridges.

onotoneELECTRONIC APPLICATIONS DIVISION, ELMSFORD, N. Y., DEPT. C9-90

IN CANADA, CONTACT ATLAS RADIO CORP., LTD., TORONTO

LEADING MAKERS OF

'11I

BATTERIES CARTRIDGES SPEAKERS TAPE HEADS MIKES ELECTRONIC TUBES

For more data, circle 9-115-1 on coupon, p. 78


TRITON TAPE CO., 62-05 30th Ave., Woodside,N.Y.-TapeTURNER CO., 909 17th St., N.E., Cedar Rapids,Iowa

UNITED AUDIO PRODUCTS (WIGO), 12 W. 18St., New York 11, N.Y.-Turntable/ChangerDual 1006, $79.95. Spkr ER -85, $21.00.ERD-12, $59.50. CX-212, $79.50. WD -12,$59.50. TW-400, $12.50. CX-2, $20.00. FW-2,$5.00.

UNIVERSITY LOUDSPEAKERS, INC., 80 S. Ken-sico Ave., White Plains, N.Y.-Spkr Series200, wide range, $28.00-$156.00. Series 100,wide range, $16.95-$83.00. LC Series, self-contained, $34.50-$150.00. Woofers, $15.00-$89.50. Tweeters, $18.00-$49.50. Networks,$3.95-$32.00. Trimensional System TMS-2*,mah, $258.00. Medallion XII System*, mahless grille, $139.95. RRL-12*, 12" 3 spkrsystem mah, $119.95. RRL-8*, 8" 3 spkrsystem mah, $99.50. S-80*, 2 -way mah,$59.95. S -9S System*, unfinished, $340.00.SLC*, stereo add-on, $43.50. Stereofiex II,mah, $110.00. Spkr Enc, $37.75-$120.00.Adapter kit 812A, $3.75. *Enclosure in-cluded.UTAH RADIO 8 ELECTRONIC CORP., 1124 E.Franklin St., Huntington, Ind.-Spkr D8J*,$17.50. D8LA*, $24.95. D8P*, $35.25.D12J**, $19.95. D12LA, $29.95. D12P**$40.75. D15P, 15" full range, $44.50.CM6J, 6" midrange, $24.50. CM8L, 8" mid-range, $37.95. Spkr Enc SC102, $24.90.*8" full range. **12" full range.VIDAIRE ELECTRONICS MFG. CORP., 44Church St., Baldwin, L.I., N.Y.- -Accessories.

VIKING OF MINNESOTA, 9600 Aldrich Ave.,S., Minneapolis 20, Minn.V -M CORP., Benton Harbor, Mich. (The VOICEof MUSIC) -Tape Rec Model 722, 4 track,$259.95. Spkr Model 168, $75.00. ChangerModel 1571, 4 speed, $50.00. Model 1586,$56.00. Turntable Model 1580, 11", $35.00.Amp Model 1404*, 2 -channel 14 watts/channel, $89.95. Turner Model 1405, AM -FM, $99.95. *Preamplifier included.

WEATHERS INDUSTRIES, 66 E. Gloucester Pike,Barrington, N.J.WEBCOR, INC., 5610 W. Bloomingdale Ave.,Chicago 39, III. -Tape Rec. #2104, 2 speeds3%, 1%, $175.00. #2103*, $139.95. #2005*,$169.95. #2001*, $199.95. #2008*, $249.95.#2101*, $199.95. #2108*, $249.95. #2107*,$349.95. *3 speeds 1%, 3%, 71,2.

Selling Stereo

(Continued from page 109)used as sales aids in the case ofconnector cables and smaller arti-cles. Different type jacks are alwaysneeded by hi-fi owners, as are cableextensions, etc. Other popular itemsare: adjustable phono base legs forlevelling, splicing tape, drawerslides, solder tools, hand tools, etc.The do-it-yourself kit market is big. . . and growing. Accordingly, it

would be foolish for a dealer to ig-nore this trend.

The accessory and replacementparts market is varied and profita-ble. Intelligent merchandising suchas fresh displays, display charts,peg -boards, show -case, stylus mi-croscope for free customer styli ex-amination, and other sales aids willcertainly multiply sales and help es-tablish your store as the stereo hi-fi center in your neighborhood.

"Has it started to act up yet?"

IN WAREHOUSES...

when It comes

UNIVERSITY

MEANS

BUSINESS!

. more business for you because you've gotthe world's widest range of specialized pagingand `talk -back speakers to choose from.Compact low -wattage units for spot coverage.Medium and high power directional types forpenetrating high noise levels. Overhead radialsfor more coverage at less cost. Bi-directionalmodels to cover two opposite areas econom-ically with a single driver. This complete choicemeans you can always specify the right speakerfor every job. No compromise ever in power,coverage, or performance. Instead, your cus-tomer gets exactly what he needs to savevaluable time, lower operating costs, increaseadministrative efficiency.

SPECIAL TALK- BACK FEATUREEach of these speakers is designed to operate as ahighly sensitive microphone for greatest convenienceand economy wherever talk -back communication isdesired. For example, anyone working in a remotearea can talk -back through the speaker to the controlpoint without having to operate a switch. When youremployees "talk -back," you save money!

MODEL IB-A New 25 watt version of world's mostwidely used medium power speaker. Lower frequencyresponse for greater fidelity.MODEL CIB-A Exclusive University wide-anglehorn produces uniform sound pattern with optimumvertical dispersion. Power rating increased to 25 watts.MODEL IBR Ideal solution for high -ceiling areasrequiring wide coverage from minimum number ofspeakers. Uniform 360° dispersion.MODEL MIS Compact reflex speaker for flushmounting in cabinets, walls, ceilings, etc. Perfectreplacement for less efficient cone speakers.These are only four of the many University pagingand talk -back speakers ... all described in the latestProduct Catalog along with all other University P.A.speakers and accessories. See your distributor, orwrite: Desk Z-9, University Loudspeakers, Inc.,80 So. Kensico Ave., White Plains, N.Y.

A Division of Ling-Temco Electronics, Inc,

116For more data, circle 9-116-1 on coupon, p. 78


GC PHONO KNOBSAs a follow-up to the firm's exact

replacement TV knob package: a com-panion replacement package for phonoknobs covering leading makes of rec-ord changers. The initial phase of thenew knob line includes 36 different

I ACTrRECORD CHANGER

WilliWEgKRNo 2= 'O4 : kt'ttó w5.4,

GOIrw A titG

items. Replacements now in the linecover Collaro, Monarch, V -M, andWebcor changers. All knobs are skin -packaged on cards that give full re-placement information. GC Electron-ics Co., 400 S. Wyman St., Rockford,Ill.For more data, circle 9-117-2 on coupon, p. 78

Additional copies ofSTEREO 1961

Available for 50¢

MASCO INTERCOMModels AC -1013 and AC -1025 are

13 and 25 master stations with 10watts of power. Installations include:up to 24 remote stations in master -to -remote; up to 25 master stations in

master -to -master; and up to 156 mas-ter and remote stations for intermixedinstallation. Stations can be operated2,000 feet apart. Other features: vol-ume controls; built-in busy signallight; all -call (optional) button; nointerference or crosstalk; and anymaster station can call another mas-ter whose power may be turned off.Mark Simpson Mfg. Co., 32-28 49thSt., Long Island City 3, N. Y.For more data, circle 9-117-3 on coupon, p. 78

DEALERS: You can sell and install 'Action' systems, and get a profitable share of thehuge intercom market. Write today for literature and details of the 'Action' demonstra-tion selling plan. Get ACTION - the most versatile system on the market at a pricethat fits 90% of the market.

_¿.2r7i-o_Arthe COMPLETEIntercommunication System

for offices, plants, stores ...PROVIDES THE RIGHT SERVICE AT EVERY POINT

one cUeisatiQe Ueatuties in One System!Now factories, professional and business offices, stores, garages, motels,warehouses can enjoy the most complete combination of essential servicesin one intercommunication system at a moderate price. ACTION! presents anew concept in flexibility - enables you to connect interphones, paging and2 -way speakers, radio and record players, audible signals, and other usefulfeatures in the same system. Only ACTION! gives you the service you need

at every point throughout your office or plant. That versatility will help yourbusiness operate with smooth, quiet efficiency. Compare services and price -and you'll get ACTION!

THE ACTION! INTERPHONEHandsome, dignified - the modern de-sign for today's offices. Every Interphoneis a master station - will call everyother phone or speaker. 4 or 8 buttons.

.1

RECORD PLAYERS, TUNERSCombination player -amplifiers reproducerecords or radio broadcasts over ACTION!loudspeakers. Can be added to systemat any time.

ELECTRIC CLOCK CHIMESDignified chime signals-- can be installed in ex-ecutive offices. Mellowchime signal containedin standard wall unitsor electric clocks onACTION! circuit.

HANDS -FREE VOICE-COMAnswer calls on either the Interphoneor the built-in, no -hands speaker, leavinghands free to write or work whileconversing.

VOICE PAGINGYou can locate your man or makeannouncements on the broadcast speakeror the powerful horn speaker in noisyrooms or outside areas.

WALL BAFFLESSuperior tonal qualityfor reproduction ofmusic, and clarity forpaging and announce-ments. Various baffleand speaker models areavailable.

SEND FOR ILLUSTRATED BROCHURE

ACTION! SYSTEMS MERIDEN, CONNECTICUTFor more data, circle 9-117-1 on coupon, p. 78


Rek-O-Kut STEREO TONEARMFeaturing a permanently attached

cable that plugs instantly into the am-plifier, the "Micropoise" arm is avail-able in two models: S-220, 12"; andS-260, 16". Both incorporate the an-chored, single -jacket cable which ter-minates in two color -coded plug-inleads, two shields, and a ground wire.This exclusive feature eliminates theneed for soldering separate wires. Pre-cise dynamic balance and stylus pres-sure are obtained by dialing the bal-ance control. S-220, $29.95. S-260,$34.95. Rek-O-Kut Co., 38-19 108th St.,Corona, N. Y.For more data, circle 9-118-2 on coupon, p. 78

YourAmperex®Distributor has

VALVOTUBES in stock

forservicingIMPORTED RADIOS,HI-FI SETS,TAPE RECORDERS &DICTATING MACHINES

To help you achieve optimum results in the repair and serv-icing of imported electronic equipment utilizing European-

made VALVO receiving tubes, your franchised Amperexdistributor now stocks the entire line of VALVO types.

iiiik:MI Le Mr\ r,a.11\\\\WI7ti! NsM21.11/w.veaiiiw ask Amperex

for the name and address ofyour nearest VALVO distributor

Amperex ELECTRONIC CORP. 230 Duffy Avenue, Hicksville,L.1.,N.Y.For more data, circle 9-118-1 on coupon, p. 78

Simpson AC-VTVMModel 715 AC-VTVM measures a -c

sine wave voltages from 0.2 my through300v RMS. Frequency response, 10cycles through 400 kc. A specially de-signed meter scale provides db mark-ing on both the voltage range posi-tions and the meter scale. Accuracy,±5% of full scale. Input impedance,minimum 1 meg @ 1 kc. Internalmultipliers, ±1% precision resistors.Ideal for hi-fi and general low levelaudio work such as hum and ripplemeasurements, i -f gain and vibrationanalyzing. $69.95. Simpson ElectricCo., 5200 W. Kinzie St., Chicago 44, Ill.For more data, circle 9-118-3 on coupon, p. 78

UtahSPEAKER -BAFFLE COMBINATION

Utilizing the new "Magni-Magic" in-verted speaker, a ready -to -use speakerand baffle combination is available infour different series: speaker -baffle,70v transformer and volume control;speaker -baffle and volume control;speaker and baffle only; and speaker -

baffle and transformer only. Dual di-ameter design features an 8" speaker,8 ohms power handling 5 watts, andscrew type terminals. Completelywired and ready for instant use. Baffle,12" wide, 91/4" high, 4" deep at top, 21/4"deep at bottom. Utah Radio & Elec-tronic Corp., 1124 E. Franklin St.,Huntington, Ind.For more data, circle 9-118-4 on coupon, p. 78

"Oh, thank you very much! I don't knowhow I can ever repay you."


Mullard FRAME GRID TRIODEA new Frame Grid r -f triode for TV

tuners, the EC97/6FY5, features high-er gain and lower noise characteris-tics. The Frame Grid construction as-sures minimum levels of microphonyand cross modulation. Uniformity re-portedly makes it possible to change

tubes without the necessity of realign-ment. Typical EC97/6FY5 character-istics: Trans -conductance, 13,000 mi-cromhos; Amplification factor, 70;Plate Voltage, 135 Volts; Heater Cur-rent, 200 ma; Heater Voltage, 6.3Volts; 600 mil and 450 mil series stringversions are also available. MullardInternational Electronics Corp., 81Spring St., N. Y. 12, N. Y.For more data, circle 9-119-2 on coupon, p. 78

Additional copies of

STEREO 1961

Available for 50c

SwitchcraftMICROPHONE CONNECTOR

Announced is a new molded femalemicrophone connector to replace theformer connector, used on certain cableassemblies. The conversion feature offemale to male, by screwing back the

ring, is the same. It is completelyshielded and has greater strength. Iteliminates solder connections and theneed for a strain release spring. Avail-able in popular lengths in assemblieswith the opposite end connections asshown. Switchcraft, Inc., 5555 N.Elston Ave., Chicago 30, Ill.For more data, circle 9-119-3 on coupon, p. 78

Jensen PHONO PARTSA new line of phonograph parts, dis-

played on a special 6 -sided, 2 ft. high"Access -O -Rack," features 9 newphono accessories mounted on a 4 -color parts center. Included in thispackage deal, for distributors and salesreps, are plastic spindle plugs, tonearm lifters, phono oil, record oil, rec-ord covers, needle inspection micros-copes, 45 rpm universal spindles andmetal 45 rpm inserts. The display con-tains also the firm's regular line ofneedles, record brushes and Silcloth.Jensen Industries, 7333 W. HarrisonSt., Forest Park, Ill.For more data, circle 9-119-4 on coupon, p. 78

to be equippedfor every call...

IN THE PHONO CARTRIDGE

BUSINESS YOU HAVE TO HAVE

THE AST

Plug -ins, conventional types ... stereo, monaural.. diamond or sapphire styli - you name it, and

Astatic has precisely the right cartridge for the instal-lation, every time. ONLY ASTATIC can offer thiscomplete answer to cartridge needs! Astatic is thesingle, dominant name in the field, produces and sellsmore cartridges every year than all others combined.This means better cartridges, better business for you-with Astatic.

Leader with Originals First with Replacements

tH[

CORP., CONNEAUT, OHIOMO In Canada: Canadian Astatic Limited, Toronto, Ontario

Export Sales: Roburn Agencies, Inc.431 Greenwich St., N. Y. 13, N. Y., U.S.A.

WORLD'S MOST FAMOUS NAME IN PHONOCARTRIDGES, NEEDLES AND MICROPHONES

TI CLINE



e YOUR NEEDLEIS DISTORTING

SOUND BY ASMUCH AS 85%(if it isn't a Fidelitone Pyramid Diamond)

A conventional needle with a rounded ball tipcan't fit the microgroove accurately. Its roundedshape prevents proper contact in the high tonalpassages. Result? Distortion and noise.

But, Fideltone's new Pyramid Diamond is shapedlike the original cutting stylus to fit the recordgroove exactly. It maintains proper contact inall frequency areas. This lowers backgroundnoise and distortion by as much as 85%, andreproduces only maximum true sound - stereoor monaural.

HERE'S WHY...

Recording 51,1,. Ordinary Needle Pyramid Diamond

Fidelitone's new Pyramid Diamond is shapedsimilar to the stylus that recorded the original

sound. It perfectly follows everycontour created by the recording

`t- stylus.

In en unmodulated, or low Irequencygroove,therecordingstylus(A) cuts a groove (W1) wideenough to let an ordinary ballpoint needle (C) and the FidelitonePyramid Diamond (B) track thecenterline of the groove accurate-ly, and contact all recorded soundimpressions.

As the groove is modulated byhigh tones, the groove width(W-2) cut by the recording stylus

(A-1) narrows. This causesthe ordinary ball needle (C-1)to rise and "pinch out" of

the record groove. Itbridges modulation crests,

mistracks centerline anddistorts sound impressions.

The Pyramid Diamond (B-1),because of its new shape, stays

solidly in the record groove,smoothly glides along the center-line positively driven by thegroove walls.

BAIL POINT DIAMOND PYRAMID DIAMOND

And the new shape of the Pyramid Diamondallows more surface contact between needle andrecord, substantially reducing contact pressure.This greatly increases needle and record life.

See your record dealer or hi-fi specialist today.Demand the Fidelitone Pyramid Point. You oweit to your records and your listening pleasure.

For the complete story on the revolutionary newPyramid Diamond, or the name of your nearestdealer, write Fidelitone, Chicago 26, Illinois.

Fidelitone"Newest shape on records"

THIS IS THE FIRST

IN A SERIES OF ADSrunning in 17 magazines. Thecombined circulation is over2,500,000. Take advantage of thispowerful selling tool. Order thecomplete line of Fidelitone nee-dles now. Profit from their sale.

Fidelitone"Newest shape on records"

Chicago 26, IllinoisFor more data, circle 9-120-1 on coupon, p. 78120

Oxford TWEETERIntroduced is a new tempo high note

tweeter, said to be designed to deliveroutstanding tone fidelity at a remark-ably low price. Features include:2" x 6" horn loaded compression for usein fully enclosed or open baffle; new-

est, completely shielded short pathmagnetic circuit; wide angle sounddispersion pattern; spherical precisionmolded phenolic; and radiating dia-phragm affixed to layer wound coilsupport. Oxford Components, 556W. Monroe St., Chicago 6, III.For more data, circle 9-120-2 on coupon, p. 78

Scott STEREO AMPLIFIERModel 222B, a new improved ver-

sion of model 222 dual channel stereoamplifier, is rated at 15 watts perchannel; a total of 30 watts by IHFMstandards. Features include: tapemonitoring facilities; separate tone

controls on each channel; tape headinputs; aluminum chassis; oversized20 watt transformers; and input forelectronic organ. Bandwidth extendsto below 25 cycles. $144.95, east of theRockies. H. H. Scott, Inc., 111 Powder -mill Rd., Maynard, Mass.For more data, circle 9-120-3 on coupon, p. 78

Additional copies ofSTEREO 1961

Available for 50¢

Chemtronics CLEANERSAnnounced: the availability of a

free "spray aid" with each 3 oz. canof Trol Aid or Tun 0 Lube. Hereto-fore, the plastic spray adaptor forpin -point applications was availableonly with 8 oz. cans. Trol Aid cleansand lubricates controls and contacts.Tun 0 Lube is used for cleaning andlubricating all tuners. Suggested deal-er net for each aerosol 3 oz. can, in-cluding free "spray aid", $.98. Chem-tronics Inc., 870 E. 52nd St., Brook-lyn, N. Y.For more data, circle 9-120-4 on coupon, p. 78

Centralab STEREO SWITCHA new remote speaker switch, known

as the 1486 stereo speaker switch,enables switching from the "mainpair" of stereo speakers. The switchalso permits the operation of all four

speakers simultaneously-. It is 1-1, 32"high and 1-29/64" wide. The 1/4" dia-meter shaft measures 1%" from thebushing with 1/2" split knurl. It is sup-plied with push -on knob and instruc-tions. Centra -lab, 900 Keefe Ave., Mil-waukee 1, Wis.For more data, circle 9-120-5 on coupon, p. 78

Walsco PHONO DRIVESA total of 17 additions to the firm's

line of replacement phone and re-corder drives is announced. These 17new drives are designed for replace-

ments on Admiral, V -M, Revere, Wol-lensak and other leading recordersand record changers. Walsco Elec-tronics Mfg. Co., Div. Textron Elec-tronics, Inc., 100 W. Green St., Rock-ford, Ill.For more data, circle 9-120-6 on coupon, p. 78


Stereo Cartridge


ever, use both lateral and verticalmotion and, therefore, the stylusmust be compliant in both direc-tions.

Dynamic mass is another con-sideration that is "old hat" butcoming into prominence lately. Thelarger the cartridge mass, the lesslikely it is to perfectly handle theturn and twist of a record groove.Also, the mechanical resonancepoint of the cartridge mass can beraised further beyond audibility,lessening the chance of impairingaudio quality, as dynamic mass ismade smaller.

Stylus size is also decidedly dif-ferent. The 1 mil LP stylus hasbeen changed to 0.7 or 0.5 forstereo records. Stylus pressure, as

NORMALPRESSURE

GREATERPRESSURE

1/ DISTORTED \

$RAPE\i

OF GROOVE

ORIGINAL SHAPEOF GROOVE

Fig. 3-Abnormally high stylus pressure willdamage a disc's soft vinyl grooves.

LARGE STYLUSPRODUCES

DISTORTEDMOTION

NEEDLEPATHS,

ARCE

..n.,al ..

SMALLERSTYLUS

REDUCESDISTORTION

r<oAo ,AVE1

RECORDSURF CE

RECORD,SIDEWALL

Fig. 4-A smaller stylus tip (RIAA suggests 0.5mil) can trace a record groove with less error,thereby resulting in lower distortion.

indicated earlier, has been de-creased accordingly. Recommendedstylus pressures are shown inCharts I and II, together with rec-ommended load resistors. Profes-sional tone arms can, naturally,operate properly at lower trackingpressures than record changers.

Styli

Diamond styli, once thought tobe indigenous to audiophiles only,are rapidly displacing sapphiretips in stereo hi-fi pickups. As a re-sult of this trend, service dealersare stocking these "gems" in in-creased numbers.

Together with the public's cur-rent awareness of a diamond sty-lus' long life, the non -permanencyof a diamond stylus is also receiv-ing intensified interest. Thus, manyservice dealers have added powermicroscopes to inspect their cus-tomers' styli. This procedure mini-mizes damage of expensive recordcollections and multiplies stylisales.

Styli can take great pressureswithout damage to themselves.However, excessive stylus pressurecan damage the relatively soft vinylof a record, as shown in Fig. 3.Therefore, stylus pressure shouldalways be checked when a customerbrings his record player into yourshop for repairs.

Another record groove destroyeris the too small or too large stylus.Remember, changing a stylus froma 1 mil to a 0.5 mil one withoutlowering tracking force will resultin four times the amount of pres-sure on the record grooves. Use thecorrect stylus size, especially in arecord changer tone arm, wheretracking force must be necessarilyhigher than in a professional -typetone arm.

The RIAA recommends a 0.5 milstylus tip, but most tips are 0.7 milbecause of the unusually lighttracking force requirements of thesmaller tip. The smaller tip, how-ever, will reduce distortion, as illus-trated in Fig. 4.

"What's wrong with your stereo?"

LOWEST NOISEwith

Mullard7025

e most troublasin #iigi Fidelity egiwMulford special design and cbnstriation, including specialmica supports and internalstrLcture make the 7025 su-perior particularly in criticalhlgt ga.n circuits where lowestlevel of hum, noise and micro-phones are repaired.

A plug -In Replacerenrt forECC83, 12AX7, 12AX7A1 1

MuIIard)OTTER Mallard TUBES

desigctedspecificallyto'ilighFidelity;,..A. 91..R>WI..d. NA

EB9'IGAiS Double DiodeECC81/13AT7 Low -noise medium p. dial biodeECC83/11AU7 Low -noise lowµ dual t lode81C1t3/12AX7 low -noise high ti dual triodeECCa5/SAQ8 OF Couble triodeECCEE/5iiQ8 Frame Grid RF Double triodeECFE2/'BU8 2F t.'ioce pentodeECL.82/881M8 Triode with Output Pen+odeEF86l6'2E7 ,ownol.e input pentodeEF94/6AÚ6 RF AP pentode

11.334/4C/t3$1 High -pourer pentode, ICO W PPEL37 High power pentode, 69 W FPEL84/64QS Miniature output pentode 20 W PPEM84;'6FIS6 Miniature tuning indicatorEZ8R/694 Miniature rectifier cathode type. 90 ma.EZ81/604 Miniature rectifier cathado type, 150 ma.GZ34/511P14 Bantam -edifier cathode type, 250 ma.7189 Mi'-ioture output pentode 20.W PP

Available at all leading disiributort.

NOW AVAILABLE: ''Mallard Cir-cuits for Audio Amplifiers" -136 pages of Stereophonic andMonophonic Audio Amplifiers,AM Tuners, Preamplifiers-only$2.50 from your dealer or bymail.

For detailed technical data andapplication information wrile:

INTERNATIONALELECTRONICS CORP.81 Spring Sxreet, New York 12, N. Y.

ELECTRONIC TECHNICIAN September, 1960Fort `rare data,, circle 9-121-1 on coupon, p. 78

121

RATED "Best BuyNOW EVEN BETTE

t$110. -,

only for those who want the ultimate

ShEAOEJ-S-3OUU IIIFM/MX STEREO TUNER

The FM tuner that has everything ... 0.950sensitivity, Interchannel Hush noise mutingsystem, "Acro-Beam" tuning eye, cascode bal-

anced input, automatic frequency control,"local -distant" switch ... now brings youthe only

FM TUNER with "CORRECTIVE"INVERSE FEEDBACK

Every high fidelity amplifier today incorpor-

ates "corrective" inverse feedback for lowerdistortion and improved response. Now, Sher-

wood brings the same performance benefits

to the S-3000 III FM Tuner; these includereduction of distortion due to overmodulationby the FM station and better quality long-distance reception.

READY FOR FM STEREO

Stereo via FM multiplex broadcasting is just

around the corner. The S-3000 III containschassis space and all control facilities to plug

in a stereo multiplex adapter. Other features

include flywheel tuning, plus 7° expandedslide rule tuning scale, cathode -follower out-

put, and front panel output level control.Sherwood Electronic Laboratories, Inc., 4300N. California Ave., Chicago 18, Ill.

(0) Other fine Sherwood Tuners:S-2000 II AM -FM Tuner $145.50S-2200 AM -FM MX Stereo Tuner $179.50

FOR COMPLETE TECHNICAL DETAILS WRITE DEPT. T-9


Stereo Packages


Does it give good stereo separationand depth? Finally, can it handlethe power peaks needed for con-vincing presentation of "large" pro-grams, such as orchestra withchoir?

Check to see that the turntableor changer (usually the latter) op-erates smoothly, without damage tothe record when the stylus is low-ered, and without noticeable flutteror wow. Also check rumble. Thisshows up as a hum that only ap-pears when the stylus touches therecord groove.

If it uses sound projection, suchas from the ends of the cabinet,check that it gives adequate stereorealism over a reasonable area,large enough to satisfy your needs.Notice particularly how movingaround affects listening quality.Some locations may make the tre-ble sound muffled. This dependsnot only on the system, but to someextent on the acoustics of the lis-tening room. If it is unsatisfacoryfrom this viewpoint, get a packagethat either has satellites to over-come the difficulty, or makes provi-sion so you can add your own, withjacks.

One problem occurs with manypackage systems: When you turnthe volume up, with bass boost ifthis is provided, the set will start abuzzing hum, due to acoustic feed-back from the loudspeaker to thephono pickup. If it only happenswhen the volume is unbearablyloud the effect may never botheryou.

The kind of floor under the in-strument can affect acoustic feed-back considerably. If it is a woodenfloor that can vibrate with the mu-sic, the trouble gets much worse.A concrete floor, providing rigidity,will almost eliminate the effect.This distinction may or may nothelp you cure the trouble, but it willexplain why it can happen at home,when it was perfectly all right atthe showroom or vice versa.

Servicing

Servicing a package stereo set isnot unlike servicing components.

The basic "ingredients" are thesame. Ignoring the portable stereophonographs for a moment, consolestereo sets frequently demand in-the -home service due to their pre -installed nature and the usual me-chanical -electrical inability of pack-age set owners.

If you intend to make house calls,you must have an audio tube caddywith audio and tuner tubes, seleni-um rectifiers, cartridges, connectorsand standard caddy equipmentsuch as solder gun, hand tools, etc.If you are not prepared to makethis small investment in tubes andcartridges, don't accept home serv-ice calls .. . you'll be wasting val-uable time and probably create theimpression of, at the very least,being inefficient.

It's a good idea to carry connec-tor markers when servicing con-soles in the home. You'd be sur-prised at the numerous wires thatmust be disconnected. Markingwires and connection points willsave considerable time when re -in-stalling the chassis.

Portable sets are similar to theolder monophonic portables, ex-cept that two amplifiers and speak-ers are used. Sometimes the secondchannel's amplifier and speaker(s)is in a separate case, connectingto an input on the main chassis.

Only a few unusual problems ex-ist in small stereo packages ; one isexcessive heat. The amplifiers in asmall case can throw off a tremen-dous amount of heat, ruining parts,especially filter capacitors. If thisis experienced, it may be judiciousto recommend ventilation holes tothe customer. The holes can bemade decorative by brass orchrome metal inserts, available atmost local hardware stores.

Another problem exhibited bysome portable stereo packages issilicon rectifiers that "short," takingthe fuseohm resistor with it.

Can a stereo package systemequal that of a components system?Cost for cost it can produce as ac-ceptable sound quality to the cus-tomer as components. But findingthe good buy in packages is verymuch a matter of sorting the wheatfrom the chaff. Really poor compo-nents are rarely as bad as reallypoor packages. Packaged systems,however, are rarely as elaborate astheir component counterparts. Norcan they offer that "extra" bass, or


the unusually fine tracking of a pro-fessional tone arm, or the versatil-ity of positioning speakers, etc.However, not everyone is partic-ularly concerned with these quali-ties; nor willing to pay for them.Thus, the package market is, andpromises to continue, as the majormass audio market. Consideringthe inherent nature of components,as well as the limited number ofdealers selling such units, compo-nents should continue to thrive inits more restricted segment of themarket.

Illustration credit: VM Corp.

EICO RECORD CHANGERModel 1007 is a 4 -speed automatic

record changer for 10 records and anautomatic/manual single -record play-er. It is supplied with a dual RC mag-netic input adapter. The cartridge

I

im 1111

oWeasily snaps in and out of the tone -arm without tools. Instead of a con-ventional stepped motor shaft ma-chined down to increasingly smalldiameters for lower record speeds, the1007 employs 4 individual intermediatecompound idlers. $59.75 with diamondand sapphire; $49.75 with 2 sapphires.Electronic Instrument Co., 33-00Northern Blvd., L. I. City 1, N. Y.For more data, circle 9-123-3 on coupon, p. 78

"Take me to your tweeter."

NO We .. enjoy your Hl -Fl OUTDOORSPATIO, GARDEN, TERRACE, PORCH

with the new wr-6

ATLAS HI-FICOAX -PROJECTOR

all-weather construction ... install it, forget it! ...or take it with you wherever you listen.

True HIGH FIDELITY TWO-WAY system -notjust a "compromise" of two horns coupled toa single diaphragm. The WT -6 comprises aweather-proof cone type driver (with 6 -inchthroat) coupled to its individual woofer horn;a separate pressure -type driver loaded to itsseparate tweeter horn. The built-in crossoverelectronic filter supplements the electro-mechanical frequency -limiting characteristicsof the 2 individual reproducers - providingfor smooth frequency division as eachspeaker functions within its engineeredrange of frequencies.All-weather .. . high efficiency ... compact. .. for all indoor and outdoor uses .

universally adjustable "U" -type rugged steelmounting . . . finished in high temperaturebaked modern beige enamel.POWER RATING 15 watts continuous

netFREQ. RESP. 140.15,000 cps $34.50IMPEDANCE 8 ohms. DISPERSION 120°DIMENSIONS bell opening 15", overall depth 12"See the WT -6 at your local distributor. Send for catalog ET -9

ATLAS SOUND CORP.1449 39th St., Brooklyn 18, N. Y.


mo re...so much more for everyone ...for everyapplication ... in the complete line ofStanton Stereo Fluxvalves*.Here is responsible performance...in foursuperb models...for all who can hear thedifference. From a gentle pianissimo to aresounding crescendo-every movementof the stylus reflects a quality touchpossessed only by the Stereo Fluxvalve.

STANTONeaperaeen

Standard: Model 711 -An ultra.linear professional pickupfor .cording channel calibration,radio stations and record evaluationby engineer. and critics...l ramwoo

Collectors Serles: Model 730-A pre -On pickup for the dise ruminating

record collector...from $29.05

Pro.Standard Series: MN II-A pro.fessi onel pickup outstanding forquality control... from 324.00

SlereePlaya Serla.: Stereo 90-A fine duality stereo magnetic Oak.up for the eudlophile..$16.S0.

LISTEN!... and you will agree Pickering has more for the best of everything in record reproduction-mono or stereo. More Oatput-More Channel Separation-More In Response-More in Record Life!In short... more to enjoy... because. there's more quality for more listening pleasure. a U.S. Patent No. 2.917.590

--Nno N a Aa r.c -"acct LISTENI-Auk fore Stereo FLUXVALVE demonstration et your Hi -Ft Dealeru t

today?

Send for Pickering Tech-Specs -a handy guide for planning a stereo highMOMa Co, INC. nuxnm. Kw rea fidelity ryutem ... addreee Dept. M90

me» rw.=..., nc.ccum., wua,e.11 carts. reds ..o.eo 11011... uc0-e.no..TA.o.eo.ee m.o...Imom...o s T.s eann, or aces... nee..waver

CPicNenng

ELECTRONIC TECHNICIAN September, 1960For more data, circle 9-123-2 on coupon, p. 78

123

Assure

OPTIMUM FMreception with

HI -PAR ANTENNASyour key to better

HI-FI INSTALLATIONSModels to suit all locations

MODEL 6Y is a 6 -element unidirectionalbroadband yagi covering the entire FM band.Its high gain, a solid 9 db avg., is the perfectanswer for fringe and weak signal areas. Re-jects co -channel interference and local noisefrom rear and sides. Light weight makes it idealfor use with rotators. Stacking boosts gain to 13db! Finest grade seamless aluminum tubing isrugged, assures long life.

MODEL F-1 isthe original,patented non -directional FMantenna whichrequires no orien-tation. It is sup-plied as a completeinstallation kit with S' mast, rugged chimneymount, 60' of 300 ohm lead-in, hardware andinstructions.

Other models include on 8 -element yogi for specificfrequencies, 5 -element yogi, and folded dipole -reflector. All are fabricated to exacting specifica-lions, and are favorably priced for dealers.

HI -PAR PRODUCTS CO.FITCHBURG, MASSACHUSETTS


L

send forthe big444 -page

.41L/EDelectronics

1961

ALLtSD siADto

ALL/ED 1961ELECTRONICS CATALOGWORLD'S BIGGEST-everything in elec-tronics at money -saving prices for Serv-ice Technicians and Engineers:

Largest selection of Electronic Parts,Tubes, Transistors Test Instruments,Meters TV Tubes, Antennas, Acces-sories Knight -Kits * - Best in Build -Your -Own Everything in Stereo Hi -FiMusic Systems & Components P.A. Sys-tems Tools Service Books Every-thing for Service Work.

ONLY $2 DOWNon ordersup to $50

Save most at ALLIED.Write for FREE 1961Catalog today !

ALLIED RADIO, Dept. 25-i100 N. Western Ave., Chicago 80, Ill.

Send FREE 1961 ALLIED Catalog.

Name

Address

City Z,111(> Stub'J

Stereo Changers


cal experience are the technician'sbest guide when servicing the me-chanical aspect of changers.

Motors

A first requirement of good rotat-ing equipment is a motor that hasbeen precision balanced andaligned to give extremely smoothbasic drive. One of three types isinvariably used: four -pole, hyster-esis, or synchronous clock -type mo-tors (used with many unusuallylight turntable, one speed players).

Most record changer and turn-table units use precision balancedfour -pole motors. Hysteresis mo-tors are not popular with most con-sumers today, primarily because oftheir attendant high cost. Precisespeed is, of course, their forte.Clock -type motors are primarilyused with single -speed, belt drivenplayers. Their fine performancecontrasts with pre -stereo concep-tions of attaining smooth speedwith only heavy turntables.

If motor lubrication points areprovided, the oiling recommenda-tions of the manufacturer should befollowed. Few service organizationsare equipped to overhaul defectivemotors, thus, if a motor proves de-fective, it is usually replaced by anew one or repaired by a special-ist.

Tone -Arms

All cartridges must be supportedby some form of pick-up arm whiletracing the complex modulations ofa record groove. Tone -arm per-formance requirements are evenmore stringent for stereo than formono records. The stylus is smaller(.5 mils to .7 mils, as compared tomono's 1 mil) and tracks at a light-er weight. Since the stereo grooveimparts vertical as well as horizon-tal motion to the cartridge, the tonearm must have maximum freedomto move in both directions. Addi-tionally, the lighter weight makesthe cartridge/tone-arm combina-tion more susceptible to skippingdue to extraneous vibrations.

Integrated cartridge/tone armassembly are currently popular, asare professional -type tone armsthat accommodate various makecartridges. Each has its advocates.

Dynamically balanced arms havestirred great interest, also. An im-pressive demonstration of what dy-

namic balancing can do is its abil-ity to continue to track a recordeven when the table is tilted to anextreme degree.

Besides this spectacular demon-stration, the dynamically balancedarm has everyday attributes thatare commendable. For example, thetone arm can minimize grooveskipping. The stylus will not jumpgrooves if someone walks across hefloor, taps the phono while it is be-

® "STATIC" TONE ARMWEIGHTWEIGHT

'1jTHIS END MUST BE HEAVIER THAN THIS END...

.., SO THIS END IS MOVED BY LATERAL

VIBRATIONS MORE THAN THIS END

© 'DYNAMIC" TONE ARM

VERTICAL SPRINGHORIZONTAL

WEIGHT

BOTH ENDS EXACTLY BALANCE, VERTICALLY E.HORIZONTALLY. SPRING IN MOUNT PROVIDES

STYLUS PRESSURE.

Fig. 2-Amazing tracking abilitytone -arms is due to balancing in two planes.

ing played, slams a door, etc. Ad-vocates of dynamic balanced armsalso claim that weight drag is elim-inated, such as arm inertia.

Dynamically balanced arms arebalanced mechanically, as opposedto static arms' gravity balance.Whereas the static arm is balancedvertically, as shown in Fig. 2A, thedynamic arm is balanced both ver-tically and horizontally, as illustrat-ed in Fig. 2B.

The static arm employs a littlemore weight at the stylus end thanat the counterbalance end (usingcounterbalance weights) to keepthe stylus in the groove. The armis, therefore, out of balance to vi-bration.

Dynamic balance overcomes thisby eliminating the out -of -balance,as far as weight is concerned. Thedownward pressure to keep thestylus in the groove is not provid-ed by weight; rather, it is main-tained by a carefully adjustedspring, in most instances. Withoutthis spring, the tone arm, with pick-up mounted, would be perfectlybalanced and the stylus would nottouch the record.

Every shop should have a tone-arm weight measuring device to

For more data, circle 9-124-2 on coupon,124

p 78


adjust a pickup to its correctpressure. Unless the manufacturer'srecommended pressure is main-tained, distortion and skipping mayresult, such as that frequently ex-perienced when loud passages arebeing played. Also, excessive rec-ord wear will be encountered.

"You can't miss our shop. It's directly acrossthe street from the ball park."

OXFORD SPEAKERS... Preferred for original equipment,

Proven for replacement.

Our catalog is available upon request.

Stromberg-CarlsonSTEREO PHONO

Model 900 stereophonic phonograph,an addition to the "Integrity Series"of component ensembles in consolecabinets, incorporates a Garrard R-210changer with diamond stereo cartridge,a Stromberg-Carlson 24 -watt ASR -333stereo amplifier and two RS -401 acous-tical labyrinth speaker systems. Zoneone prices: $279.95, in mahogany;$289.95 in walnut, limed oak or cherry.Stromberg-Carlson, 1400 N. Goodman,Rochester 3, N. Y.For more data, circle 9-125-3 on coupon, p. 78

American CB MICROPHONESAnnounced are six models in the new

"208" series of citizens band micro-phones. Employed is a "slide -lock"switch to assure instant on -off actionor lock -on for continuous use. This"slide -lock" switch is claimed to bethe only one available in this newfield. Frequency response, 40-8,000 cps.Model B -208-A (ceramic) and X -208-A(crystal) with normally open mike and2 -conductor cable, $12.50; B -208-B andX -208-B, same features and price,have normally closed mikes. B-208(ceramic) and X-208 (crystal) with-out the "slide -lock" switch and withsingle conductor cable, $10.60. Ameri-can Microphone Mfg. Co., 400 S. Wy-man St., Rockford, Ill.For more data, circle 9-125-4 on coupon, p. 78

WALTZ ME AROUND AGAIN, WILLIE!A phrase aimed for increasing your profits.Since the original equipment manufacturer de-mands speakers to the most exacting electricalcharacteristics .. and demands OXFORD .. .WHY DON'T YOU? Oxford, major suppliers fororiginal equipment provides the finest replace-ment speakers for any and every application.A complete line for your every need.

OXFORD Components,A Division of Oxford Electric Corp.

556 West Monroe St., Chicago 6, IllinoisOxford Speakers are available from

recognized electronic parts distributors.

;.21,1-.21,1,`. . s ,

{ :;-,... :9.

3 REASONS WHY YOU SHOULD

RECOMMENDH. H. SCOTTSTEREO COMPONENTS1. H. H. Scott specifications are always accu

rate. Only H. H. Scott of all manufacturers,performs all measurements according to

strict IHFM standards. Only H. H. Scottguarantees that every component Will meetor exceed its published specifications.

2. H. H. Scott uses many exclusive circuit fea-tures: copper -bonded -to -aluminum chassis,stand-up resistors, spacious chassis layout

. all contribute to longer componentlife, easier servicing.

3. H. H. Scott amplifiers and tuners are de-signed to the highest standards. Only

H. H. Scott, of all manufacturers, silver -plates critical FM front ends . . . onlyH. H. Scott uses extra -heavy, speciallywound transformers to assure wattage asspecified throughout the entire audio range.

20911 50 WATT STEREO AMPLIFIER

H.H. SCOTTII. H. Scott Inc., Dept. ET -9,111 Powdermill Rd., Maynard, Mass.

Yes ... I want advance technicalinformation on new H. H. Scott products. Please send me your new technical bulletins and your latestcatalog.

Name

Address

City StateExport:Telesco International, 36 W. 40th St., NYCr

i




MAKING

Model 7 Stereo Console

World's finest preamplifierThe man who cherishes really fine pos-sessions will never cease to enjoy theprecision, sureness, and ease with whichthis instrument responds. His stereocomponent system, based on Marantz,has started off with a technical superi-ority well above those employing con-ventional good makes.Briefest examination, inside or out, willdisclose that the Stereo Console is dis-tinctly alone in its category of quality.A comparison at your authorizedMarantz dealer will show you thedifference.

SENSITIVE t/2 millivolt for 1 volt output!QUIET 0.8 microvolts equ. noise Input!UNDISTORTED .02% 1.M @ 2 volts output!PRECISE RIAA curve accurate to 1/2 db!

NOTE: The model 8 Stereo Amplifier (35 wattsper channel) is a perfect playmate for topperformance.

WRITE FOR FREE BOOKLET 410 TO:

a nit II wiz25-14 BROADWAY, LONG ISLAND CITY 6, N. Y.


DON'T WASTE TIME

. _\CONNECTING CORDSw'

SWITCHCRAFT

INTERCONNECTING- CORD

Before you take time to make up aspecial cord to connect 2 units,check or write for SwitchcraftCatalog S-590.Over 190 Molded Cables with dif-ferent type connectors and lengths.Stocked by Electronic Parts, Musical andPhoto Distributors.

5583 N. Elston Ave., Chicago 30, III.Canadian Rep.: Atlas Radio Corp., Ltd.,

50 Wingold Ave., Toronto, Ontario

Stereo Disc Puzzle(Continued from page 89)

al motion, and the very wide dis-tance between walls, indicatingthat the stylus will trace the grooveat a greater -than -normal depth-or, in other words, vertical modu-lation in a downward motion.

The second drawing shows thestylus riding high, due to narrowgroove walls pinching it upwards.

ssIte,.

5

2

i

UNMODULATEO ORREFERENCE GROOVE

T \Y

/ 2

2

G6

I

OUTERSIDEWALL

6 31

CENTERGROOVE

'I 2 15 13

I/INNER siDEw'ALL I

Fig. 5-When simultaneous signals from eachgroove wall creates lateral and vertical forces-with conditions varying from instant-to-in-stant-their combined effect establishes thestylus' instantaneous position in the complexrecord groove. See text!

No lateral movement is indicatedby the center line not deviatingfrom the reference groove center.Lateral movement is not indicatedin the third drawing for the samereason. In contrast to the seconddrawing, however, the stylus is rid-ing low in the groove because of thegreat distance between sidewalls. Inthe fourth drawing, the stylus isdisplaced to the right since the

groove center is to the right of thereference groove. The vertical dis-placement is at reference height.This may be seen in the groovedrawing by the sidewall-to-sidewalldistance being equal to the widthof the unmodulated referencegroove. The groove extension pastthe reference groove from points 3to 6 is countered by the shift ofthe inner side wall groove frompoint 1 to 4.

Remembering that the stylus con-tacts both sidewalls at any giveninstant and its relative groovewidth and groove center transmitsintelligence to two cartridge ele-ments at the same time, should for-ever still the reasoning of only onewall containing the intelligence ofone channel, except for initial anal-ysis purposes. The stylus, there-fore, moves due to the combinationof two signals forming the shapeand relative position of both side-walls, rather than two independentsignals forming two independentsidewalls.

Sonotone CARTRIDGEModel 9T turnover type ceramic

cartridge plays all speeds and eitherstereo or monophonic records. Flat re-sponse, ± 1 db over the entire audiblerecording range of 20 to 17,000 cycleswith smooth rolloff to 20,000 cycles.High compliance reduces trackingpressure to 2-4 grams for professional

tonearms. Improvements include: agold-plated metal cover to shield thecartridge mechanically and electri-cally; and the unbreakable needle as-sembly is designed to prevent damageto the styli. $16.50 with sapphire tips.$19.50 with diamond -sapphire combi-nation. Sonotone Corp., Elmsford,N. Y.For more data, circle 9-126-3 on coupon, p. 78

For more data, circle 9-126-2 on coupon, p. 78126 ELECTRONIC TECHNICIAN September, 1960

Action Systems 117Agency: The Haydon Company, Inc.

Aerovox Corp. 76Agency: lescarboura Advertising, Inc.

Allied Radio Corp. 124Agency: George Brodsky Advertising, Inc.

American Television and Radio Co. 58Agency: Firestone Goodman Advertising,Inc.

Amperex Electronic Corp. 118Agency: Sam Groden, Inc.

Arrow Fastener Co., Inc. 73Agency: Thematic Advertising Production,Inc.

Astatic Corp. 119Agency: R. J. McCallister Co.

Atlas Sound Corp. 123Agency: Zam & Kirshner, Inc.

B & K Manufacturing Co. 54Agency: Henry H. Teplitz Advertising Agency

Belden Manufacturing Co. 19Agency: The Fensholt Advertising Agency

Blonder -Tongue Laboratories, Inc. 22Agency: Gilbert & Felix, Inc.

British Industries Corp. 93Agency: Mogul, Williams & Saylor, Inc.

Bussmann Manufacturing Co. 12Agency: Henderson Advertising Co.

Castle Television Tuner Service 74

CBS Electronics 63Agency: Bennett & Northrop, Inc.

Centralab Division, Globe -Union Inc 8Agency: Stral Advertising

Channel Master Corp. 4, 5, 7, 9, 11Agency: Duso Advertising Inc.

Chicago Standard Transformer Corp..... 68Agency: Stral Advertising Co.

Cornell Dubilier Electronics Div. 2, 3Agency: Friend -Reiss Advertising, Inc

Delco Radio Division 31Agency: Campbell -Ewald Co.

DuPont de Nemours & Co. (Mylar) 59Agency: Batten, Barton, Durstine & Osborn

EICOAgency: Zam & Kirshner, Inc.

Electronic TechnicianElectro -Voice, Inc.

Agency: The Jaqua Company

113

INDEX TO ADVERTISERS

September, 1960

Greyhound Corp. 53Agency: Grey Advertising Agency, Inc.

Harman-Kardon 80Agency: The Wexton Co.

Hi -Par Products Co. 124

Illinois Condenser Co. 20Agency: Sander Rodkin Advertising Agency,Ltd.

International Electronics Corp. 121

Agency: Schneider-Stogel Co.

Jensen Manufacturing Co. 128Agency: Burton Browne Advertising

Jerrold Electronics Corp. 6, 97Agency: Irving Gould Advertising

JFD Electronics Corp. 28, 29Agency: Delphi Advertising Inc.

JW Electronics 70Agency: Henry H. Teplitz Advertising

Krylon, Inc. 76Agency: Gray & Rogers

Littelfuse, Inc. Cover IIAgency: Burton Browne Advertising

L.I. Electro -Labs, Inc. 58Agency: Sternfield-Godley, Inc.

Luxo Lamp Corp. 58Agency: Tech -Ad Graphics, Inc.

Mallory & Co., Inc., P. R. 26, 27Agency: The Aitken-Kynett Co.

M tz Co. 126Agency: Dobbs Advertising Co., Inc.

Mercury Electronics Corp. 24, 25Agency: Nat Kerman

Mosley Electronics, Inc. 77Agency: H. George Bloch, Inc.

Moss Electronic, Inc. 66Agency: Bass & Company

Mullard 121

Agency: Schneider-Stogel Co.

Oxford Components 125Agency: Sander Rodkin Advertising Agency,

64 Ltd.

99

Fidelitone, Inc. 120Agency: W. D. Lyon Company

Fisher Radio Corporation 84Agency: Vanguard Advertising

Garrard Div. 93Agency: Mogul, Williams & Saylor, Inc.

General Electric Co.-TV Receivers 21

Agency: Young & Rubicam, Inc.General Electric Co.-Tubes 16, 17, 50

Agency: Maxon, Inc.

Perma-Power Co. 10

Agency: Stral Advertising Co.Philco Corp. 13, 14, 15, 82, 83

Agency: Maxwell Associates, Inc.

Pickering & Co. 123Agency: Irving Greene Advertising

Planet Sales Corp. 70Agency: Gordon Pihl and Assoc.

Precision Tuner Service 77

Radio Corporation of America Cover IVAgency: Al Paul Lefton Company

Raytheon Company 56, 57Agency: Fuller & Smith & Ross, Inc

RCA Institutes, Inc. 69Agency: Al Paul Lefton Company

Rek-O-Kut Co., Inc. 96Agency: The Wexton Company, Inc.

Remington Rand Univac 30Agency: Mullen & Associates, Inc.

Rider Publisher, Inc., John F. 72

Agency: Gilbert & Felix, Inc.

Sarkes, Tarzian, Inc., Tuner Div. 66Agency: H. L. Ross Advertising

Scott, Inc., H. H. 125

Agency: Arnold & Company, Inc.Seco Electronics, Inc. 71, 73, 75

Agency: Firestone -Goodman Advertising, Inc.Sencore 60, 61

Agency: R. N. Johnson AdvertisingSherwood Electronic Laboratories, Inc. .. 122

Agency: Burton Browne AdvertisingSonotone Corp. 115

Agency: Doherty, Clifford, Steers & Shen -field, Inc.

South River Metal Products Co., Inc 20Agency: South River Advertising & Printing

Sprague Products Co. Cover IIIAgency: The Harry P. Bridge Co

Stromberg-Carlson 101

Agency: D'Arcy Advertising CompanySwitchcraft, Inc. 126

Agency: Jacobson & Tonne AdvertisingSylvania Div., General Telephone &

Electronics 18, 32Agency: Kudner Agency, Inc.

The Thorens Company 110Agency: James Thomas Chirurg Company

Tung -Sol Electric Inc. 67Agency: E. M. Freystadt Assoc., Inc.

Ungar Electric Tools, Inc. 23Agency: Len Woolf Co. Advertising Agency

United Scientific Laboratories, Inc. 74Agency: Sam Singer Advertising

University Loudspeakers, Inc. 116Agency: John Jason, Inc.

Utah Radio & Electronic Corp. 95Agency: Wright, Campbell & Suitt, Inc.

V -M Corporation 103Agency: Mayer, Klann, Linabury Advertising,Inc.

Ward Products Corp. 24Agency: Jay Shea Inc.

Xcelite, Inc. 30Agency: Harold Warner Advertising, Inc.

Zenith Radio Corporation 48, 49Agency: Foote, Cone & Belding

While every precaution is taken to insureaccuracy, we cannot guarantee against thepossibility of an occasional change or omis-sion in the preparation of this index.


C751 YOURSELF

THESE

ourABOUT BUYING OFF -BRAND SPEAKERS

Can I Tell My CustomersThe Name Of The

Speaker I've Installed?Jensen is a name you can mention withpride and confidence. Jensen Vikingand Weathermaster speakers benefitfrom the tremendous prestige ofJensen's HiFi lines.

* * * * *Do I Pay More For

Jensen?No. You may find an off -brand "deal"occasionally, but you get consistentcompetitive year -'round lowest cost andhighest quality when you concentrateon Jensen.

*****Can Off -Brands Give MeProof Of Performance?

Jensen has designed every type ofspeaker for the military. Jensen speakershave been under the pole ...and aroundthe world-outside submarines. Thisknow-how is a bonus extra in everyJensen speaker.

*****How About Availability?

Jensen speakers are stocked by finejobbers and distributors everywhere.You can depend on replacements beingavailable.

4enenLOUDSPEAKERS

COMPARE OFF -BRAND ANSWERS TO JENSEN ANSWERS . . .

... you'll find once again that there is somethingbetter from .. enen MANUFACTURING COMPANY

DIVISION OF THE MUTER CO. 6601 S. Laramie Avenue, Chicago 38, Illinois

IN CANADA: RENFREW ELECTRIC CO., LTD., TORONTO IN MEXICO: UNIVERSAL DE MEXICO, S.A., MEXICO D.F.For more data, circle 9-128-1 on coupon, p. 78

128 (148 pages in this issue, including Circuit Digests)ELECTRONIC TECHNICIAN September, 1960

0

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September 1960ELECTRONICTECHNICIAN 583

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Electronic Technician

CIRCUIT 83DIGEST 4J

An Editorial Service of ELECTRONIC TECHNICIAN, INC. 480 Lexington Ave., New York 17, N.Y.

ELECTRONICTECHNICIAN S84

CIRCUIT DIGESTT-1009

AUDIO OUTPUT(MATCHED PAIR)

PIN I OFJI

PHILCOTransistor PortableRadio Model T-66

PIN I

OFYEL. LEAD

R16 3.0V

NOTE'PIN 2 OF SWITO POS. TERM.

YEL. LEAD

PIN 4 OF SWITO NEG.TERMRED LEAD

T- 1003AUDIO DRIVER

PIN 3 OF SW IRED LEAD

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T-66, Code 126: TR1, Converter Transistor changed to T-1877, Part No. 34-6000-41.T2, 1st i -f Transformer changed to Part No. 32-4800-2.


CIRCUIT584DIGEST

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2.5

60

6

ALL VOLTAGES MEASURED - +

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An Editorial Service of ELECTRONIC TECHNICIAN, INC. -i 480 Lexington Ave., New York 17, N.Y.

TO REMOVE BACK

REMOVING BACK AND BEZEL

TO REMOVE

ESCUTCHEON

September 1960ELECTRONICTECHNICIAN 588

CIRCUIT DIGEST

MOTOROLATV (Transistorized)Chassis TS -432Model 19P1 "Astronaut"

4434sr 7F /SrIFrES7 ECEPT

C/03

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CIRCUIT c88DIGEST 41,

ELECTRONICTECH N ICIAN

CIRCUIT DIGESTS

In This Issue (No. 97)Circuit Digest Schematic No.

ANDREA 587TV Chassis VRT-123 Series

ELECTROHOME, Canada . . 585TV Models Breton, Breton "A", Burnaby

MOTOROLA 588TV (Transistorized) TV Chassis TS -432

Model 19P1 "Astronaut"

September . 1960

Trademark

PHILCO 584Transistor Portable Radio

Model T-66

RCA 586TV Chassis KCS131 Series

TANDBERG 583Tape Recorder, 4 -Track

Model 5

More Data on Reverse Side

SET WITH BACK REMOVED AND ENERGY CELL INSTALLED

TV (Transistorized)Chassis TS -432Model 19P1 "Astronaut"


CIRCUIT DIGEST

588

MASTMAGIC

ANTSW

VHF ANT

UHF ANT

AC LINEINPUT

OUT

VHFV

UHF

AC

1ST IF TEST RECEPTBASE INPUT

TO SEPARATE CHASSIS FROM PIX TUBE

48A134468AUDIO OUT

HEATRADIATORS

ENERGY CELL

YOKE

POWERTRANS

48A13446¢AUDIO DRIVE

LADS

AUDIO OUTPUTTRANS

CHARGING CUTOFF CONTROL'CAUTION- DO NOT ADJUSTSEE SERVICE MANUAL. 1

48A134454Qo F

DOTS481(134473AGC AMP 48A134454

DOT2 ND IF

AUTOMATICENERGY CELL f.

AC CHANGE OVERSW

48A1345013RD IFQ

48A1344571ST VIDEO AMP

VVIDEO DEI

TEST RECEPT

V48A134456

AUDIO If

3RD IF)TRANS

4E1747648iVIDEO DET

I N 5411c:.AT10 DET;r i

'RATIODET

TRANS

BLUELEAD

FOCUS ADJ STRIP(NOT ON ALL MODELS)CONNECT BLUE LEAD TOONE OF THREE TAPSGIVING BEST OVERALLFOCUS.

48A134463FILTER

AGCCONTROL

IN1218PWR RECT

3446GATEAGC ATE

rJ HEAT RADIATOR

YOKE SOCKET

ENERGY CELLUU O

B+ SETCONTROL

INSULATORB GREASE

VERT BIASCONTROL

1N1169

VIDEOSUPPLY

DIODE

481(134478VIDEO OUT

DR)VEDRIVER

INPUT

48A134465HORIZ BUFFER

ON OFF SW ' LOCALRANGE

B VOLUME i I SWITCH

CHANNEL I

a+-FRINGt

SEL

FINETUNING

CONTRAST,.

VERT HOLD

lIJJ

VERT SIZE

VIDEOBIAS

CONTROL

4811134461VERT OUTPUT

8 GREASE

YINSULAT0RPPOSITESIDE)

4 AMP SLO-BLO- LINE FUSE651(754949

48A134464 481(134473SYNC SEP VERT OSC

3481(473 VERT BLOCKING

PHASE INV/ DIODE

481(640754''.._HORIZ PHASE DET

48K742698

BLOCKINGOSC

HOR IZ

TRANS

riSUBURBAN

48A1Ó C485

Go --DOT

48A13486MIXER

pf0-DOT4803104

Cile- DOT

TUNER

BRIGHTNESS

HORIZ HOLD

VERT LIN

HORIZ TESTRECEPT

48A134462HORIZ OSC

JUMPER IN NORMAL OPER POSITION.CAUTION -SEE SERVICE MANUAL BEFORE REMOVIN

1111169G2 SUPPLY

DIODE

HORIZOUTPUT

TRHV

ANS

HORIZRINGING

COIL

48A134 460HORIZ DRIVER

1S2AHV

DIODE

HORIZ SIZE

CAUTION- HORIZ OUTPUT TRANSISTORMAY BY DAMAGED IF HV IS ARCED. USEHV PROBE TO MEASURE.

48A134459HORIZ

OUTPUT

HORIZ

Vi BIAS T

CONTROL

484134467DAMPER

DIODE

Copyright 1960 by ELECTRONIC TECHNICIAN, INC. 480 Lexington Ave., New York 17, N. Y.

PARTS LOCATIONS


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ST EREO - americanradiohistory.com · 2019-07-17 · form of projection unit. Acoustic boundaries...

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