Audio magazine June 1959
JU~E/, 1959
;';o-~'
.,
www.americanradiohistory.com
AmericanRadioHistory.Com
';O¢
MUSIO
MATES!
RCA-71 99 and RCA-7027-A . . . Perfect Pair For H igh-Fide lity Amplifier Design s
Offer them a "top" note. Send your "deepest" bass. Blast your "fullest" fortissimo
at them. N ever fear the outcome if your high-fidelity amplifier is designed around
this "perfect pair" ....RCA-7199, medium-mu triode sharp-cutoff pentode and
RCA-7027-A, beam power tube.
Study the sensitivity of the high-gill pentode unit of the RCA-7199 . .. wonderful for use in a low-noise low-hum amplifier; consider the medium-mu triode
unit ... ideally suited for use in a phase splitter. On the masculine side of the
table is the other "mate", RCA-7027-A, developed specifically to reproduce the
"big sounds". A pair of 7027-A's in a push-pull class A B l circuit utilizing feedback and driven by a 7199 with an input signal of 2 volts can deliver a power
output up to 76 watts with total harmonic distortion of less than 0.5 % with a
hum and noise level of 85 db below 76 watts.
Ask your RCA F ield Representative for the details on the H igh-Fidelity
"Music Mates" .. . RCA-7199 and R CA-7027-A. F or technical bulletins, write
RCA Commercial Engineering, Section F-91-DE, Harrison, N . J .
RCA-71 99 and RCA-7027-A .. . music motes
and q uo /ity motes . .. blend into a system
th at p ro vides music re p roductio n at its
finest!
EAST: 744 Broo d Street, Newark 2, N. J.
HUmbo ldt 5-3900
•
U
RADIO CORPORATION OF AMERICA
e Electron Tube Division
Harrison, N. J.
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MIDWEST: Suite 1154, MerchondiseMort Plaza
Chicag o 54, Illinois. WHitehall 4-2900
WEST: 6355 E. Washingto n Boulevard
l o s An geles 22, Ca lif. RAym ond 3-83 6 1
JUNE, 1959
VOL. 43, No. 6
Successor to RADIO, Est. 1917.
ENGINEEIIING
MUSIC
SOUND REPRODUCTION
C. G. McPl'oud, Editor and Publishel'
Henry A. Schober, Business Manager
Harrie K. Richardson, Associate Editor
Linda Sueskind, Assistant Editor
Janet M. Durgin, Production Manager
Edgar E. Newman, Circulation Director
Sanford L. Cahn, Advel'lising Dh'ectOi'
Midwest RepresentativeW. A . Cook and Associates
161 East Grand Ave., Chicago 11, Ill.
West Coast R epresentativeJames C. Galloway
6535 Wilshire Boulevard, Los Angeles 48, Calif.
CONTE ITS
Audioclinic-J oseph Giovanelli
Letters
New Literature
Audio ETC-Eclwal'cl Tatnall Canby
Editor's Review ..................................................................................
The TWI P A2--A Comprehensive Tape Preamplifier-AI·t!Hw W. Wa yne .
The Trimensional Stereo Speaker System-Victol' BI'ocinel'
Two More Ears-M. David W eisbcI'g
Tape Guide-How Many Heads for the 'r ape Recorder-Hen nan B UI's tein ....
Cover Story-An interesting hi-fi ancl Hctmmoncl Ol'gan I nstallationR . G. Sohlb e?'g .....................................................................................
Equipment Profile-((Dual)} Model 1006 l'eeol'(1 change?'- Geneml E lectl'ic
Stel'eo Classic amplifie1', MS-4 000- Connoisse~w Typ e B tmnscI'iption
tUI'ntable-Mim'olift phono al'm contl'ol- K ingclom (( Omega)} spealce?'
system
............................ . . ..
Standard Methods of Measurements For Tuners-Part II ............................. .
Record Revue- Eclwal'd Tatnall Canby
Jazz and All That-Chafles A. Rob eft son .
About Music-Hal'old LatV?'en ce
New Products
......................................................................................................
Industry Notes & People
................... .... ....... ... .
Advertising Index
2
6
6
10
14
17
21
24
28
36
38
48
54
60
66
68
79
80
COVER PHOTO-Part of the home installation of R. G. Solhberg, Pasadena,
Californi a. Further description and more photos of this
unique system appear on page 36.
AUDIO (title registered U. S. Pat. oa.) is published monthly by Radio Magazines, Inc. , Henry A. Schober, Presidenl:
C. G. McProud, Secretary. Ji:xecutive and Editorial Omres, 204 Front St., Mjneola, N. Y. Snbscription rate&-U. S.
Possessions, Canada and Menco. $4.00 tor one year, $1.00 for two years, aU other countries, $5.00 per yenr. Single
copies 50¢ . . Printed In U.S.A. at Lancasier, Pa. AI! rights reserved. Entire contents copyrighted 1959 by Radio Magnzines.
Inc. Entered as Second Class Matter February 9, 1950 at the Post Omce, Lancaster. Pa. under tbe act ot March 3. 1819.
RADIO MAGAZINES, INC., P. O. Box 629, MINEOLA, N. Y.
Postmaster: Send Form 3579 to AUDIO, P. O. Box 629, Mineola, N. Y.
AUD IO. •
JUNE, 1959
www.americanradiohistory.com
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The NEW
SLIM-LINED
GRAMPIAN
DP4 DYNAMIC
MICROPHONE
with
UNIFORM, WIDE-RANGE
FREQUENCY RESPONSE
AUDIOCLINIC??
JOSEPH GIOVANELLI ':'
A Complex Listening Room
Q. The problem is to design and install
a listening situation w71 m'e a maxil1111t1n
numbel' of individuals can a1tdit any of
twelve channels of classical ?n1tsic matel"ial
through crystal earp hones (perhaps 20-50)
built into tables in a lm'ge l·oom. The nU1nbel' of a1tditors will vary at any mo'ment
[Tom mini1n1tm to maximum for any of the
twe lve channels and switch'ing clicks and
level variations must be held to an absolule
minimum. The crystal phones have a l'esponse of 10Q-8000 cps. A ll of the auclitol's
will be located within 50-150 feet of the
sound source.
1. How are high impedance phones (50,000 ohlns) best connected to such a switching m'rangement?
2. I s there any pracUcal reason why two
one-q1ta?·ter tl'ack heads on one tape elecle
(plus two one-quarter track erase heads)
cannot s1tpply the material for 4 of these
cl/annels? Can these channels be erased,
I'ecorded and played back sepamtely with
ease? D. H. E., EochesteT, N. Y.
A. 1. The phones cau be driven very
* 3420 Newkirk Ave., Bl'oo7clyn 3, N. Y.
nicely from cathode followers because the
wattage required fo r each headset would
be measured in milliwatts r ather than
watts. A few milliw::!.tts would be enough.
Remember that crystal phones are voltageoperated devices.
If I were making this installation, I
would proceed as follows: Since there are
12 amplifiers and possibly 50 headsets, I
would not use a separate amplifier for each
headset. The number of tubes and other
componeuts would be staggering, and main·
tenance would become a major problem.
E"en my proposal will encompass quite a
bit of circuitry. For simplicity, assume
that you a re going to use 20 headsets. The
ou tpu t of each program channel is fed 'into
four cathod e followers, each of whose impedance is made as low as possible. Each
cathode follower will supply a maximum
of five headsets. The coupling capacitor
from each cathode follower should be quite
large, 0.25 J.tf or perhaps as high as 1.0 J.tf .
The far sides of each of these capacitors
are terminated with 470·k resistors. ( There
will be 48 cathode followers, and hence 48
separate terminations.) Divide your phones
into 4 groups, 5 per group. Each headset
should be provided with its own 50-K
CATHODE
FOLLOWERS
PROG RAM
SOURCES
I
I
I
I
o
o
o
0. i0J P ) 0
OE
o
·0
0
-=-
L-+-__~ TO
SECOND GROUP
OF 5 SWITCHES
L-_f-_ _~TO
THIRD GROUP
OF 5 SWITCHES
2 --i1--_~
L
--I---4--_- TO
FOURTH GROUP
OF 5 SWITCHES
3-1I _ - - . . J
12 ...- - - - 1
Fig . 1.
2
AUDIO
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•
JUNE, 1959
DON'T COMPROMISE
WITH QUALITY •••
The advantages
are all In .avor
o.the
CHANGER
IJ
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It's
It's
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The Garrard is
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Garrard's
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Garrard atro rds
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platform, the
Garrard act ua ll y
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more carefull y
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hand - definitely
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or turntable.
weight. thus
insuring
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and record wear.
transcript ion
Changers
comparable to the
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Convenient
foolproof pusher
engineered to
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I t i s precision-
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precisely you
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Irs
With the
Garrard insures
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aluminum tone
It's
turntables .
turnt~ble. w ith
the tr emen do lls
added advanlage
o f automatic
play when
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Pre-wired for
stereo- can be
installed in
minutes.
There's a Garrard for every high fidelity system. Fully wired for Stereo and Monaural records.
~
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301
TranscrlpuoCl
Tumtlbl.
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M_'TID
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Canadian Inquiries to Chos. W. Pointon, ltd., 6 Alcina Ave ., Toronto
Te"ilorie. olher Ihon U.S.A. and Canada 10 Garrard Engineering & Mfg. Co., lId., Swindon, Wilts., England
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Despite il s many
advantages, the
cost of a Garrard
Changer is st ill
less than a
IlI rntabJe with
separate arm .
Backed by
Garrard's
36-year record
of perfect.
I rouble-free
performance.
New Comparator Guide - FREE
Garrard Sales CorporatioD. Dept. m·',19.
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Please seDd your Dew comparator gu/cJe
which compares all Garrard playen IIIIIf
thNrunee_________________________
Address.s_ _ __ __ __ _ _ __ _
City
State-
';
Most important
of all, "~est Buy" means
BEST LISTENING - at low cost. The
Duotone non-magnetic' stereo cartridge is
the vi.t al link between the prom'ise' of stereo
r~1FordinQiand yoor ultimate enjoyment of glorious
fun-dimensional sound. Budget-priced but not
budget-min'ded, the Duotone cartridge deli~ers
highest o~,put, perfect compliance hum-free performance and here's a Duotone bonus: lowest replacement
cost of diamond-sapphire stylus.
.
potentiometer for individual volume adj ustment. Each phone is also fitted with a
switching circuit such that you can switch
to any of the 12 program sources.
Here is where the grouping comes in
and where things can get complicated. R~
member that there are foUl' cathode fo~
lowers pel' program channel. Each is intended to feed a particular group of five
headsets. We will arbitrarily number each
cathode follower of a given source 1, 2, 3,
.
,. 4. Cathode follo~r 1 of each \ili.a nnel
will .feed group 1 as follows:
1. Connect the arms of the five switches
(A, B , C, D, and E ) in group 1 to their
respective potentiometers and phones.
2_ Connect position 1 of switch A of
group 1 to cathode follower 1 of program
channell.
3. Connect position 2 of switch A of
group 1 to cathode follower 1 of program
channel 2.
4_ Connect position 3 of switch A of
group 1 to cathode follower 1 of program
channel 3.
5. Proceed until all 12 positions of the
switch are connected.
This will allow one pair of headphones
in one group to receive any of the program
channels. Switch B of group 1 is similarly
wired to cathode follower 1 of each of the
12 program sources. Positions C, D, and E
are similarly connected. Group 2 is wired
in the same manner, except· that all switch
' pU~'"WL1~ are wired to cathode follower No.
of each program channel. Proceed likewise for gronps 3 and 4.
The system should incorporate a VUmeter circuit which can be switched to auy j$
of the inputs of the 12 program preamplifiers in order to determine whether enough . I
level is being sent out to supply adequate
listening level to' the ~roups of headphones.
Note that I am loading the cathode :#.
followers as lightly as possible. This is ~.,­
.done in order that the level will remain t~
' substantially constant with a load of from
1 headset to 5 headsets. There should be
no . switching clicks, .e.~en ,~hen a listener
sWItches to a group ~ WhICh no Olle else
is listening. This is accomplished through
the use of the 470-k grid resistors : they
keep the capacitors charged even when they
are not loaded by phones. F igure 1 shows
the method of wiring one group of headphones. The diagram should be followed for
each of the remaining three groups, Figure
2 shows the detail for a typical cathode
follower.
,;
You should be able to use two 4-track
tapeheads ill the manner you suggest, since
each actually has only two ''heads,'' not
four. They are spaced so as to cover tracks
1 and 3, counting from t he top. The second
head is mounted slightly lower and. covers
tracks 2 and 4. However, there is one thing
which must be done. If you wish all four
tracks to play at once, they must be recorded in t he same direction, not alternately
as in the usual 4-track machine.
Erasing an individqlll tape presents seri-
.
(Continued on page 73)
Write for complete data and specifications.
12AU7
Manu'odute~s 01
B+ 250V
'he Wo,/d's FineJ' Phonograph Need/eJ
\\\\\\,\\\\~ COMP~NY,
I~C.
,
LOCUST 'STREET
•
KEYPORT, N. J.
Fig .
4
,
.
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~.
AUDIO ;A~
JUNE, 1959
THE PEERLESS K-241-D (20-20 Plus)
INPUT TRANSFORMER
The K-241-D is a 20-20 Plus tl'ansfol'mel' of compal'atively small
size in l'elation to its performance characteristics. Its primary balance
places it in a class with repeating coils (See Chal't C). It is magnetically
shi elded to 90 db. The following charts show its superb performance.
They demonstrate the quality of Peerless whi ch can h elp
solve your input transformer problems.
-
::fl-j 11 111111111
~}-nllllllllill
<I
5
6
7 8
"
DIAGRAM
--
:::: ..... r---
" I',
9 1
.,
1
100
10000
A-Frequency Response K-241-D
Freq uency response curves fo r four op er·
ating conditions, divided into two parts.
Th e first sho ws res pon se at maximum
rated power level wit h the transformer
te rminat ed resist ively and unterminate d.
The same condi tions of operation are
shown in the second part except fo r the
- 60 dbm level wh ich is repre se ntati ve
of microphone output. Extreme performance
sta bility is illu strated by these frequen cy responses taken at wi dely different power level s and
under two extremes of operations; that is, with open ci rcuited seco ndary and with fully loaded secondary. Performances
between these extremes 'are within t he illustrated limiting curves.
100000
- - - - - TE RMINATED
FREQUENCY' IN CYCLES PER SECOND
DIAGRAM B-Harmonic Distortion K-241-D
Di stort io n characteristic s are sh own und er
three cond ition s.
a. Input at + 8 dbm, secondary open circuited
\ a
b.
Input at + 8 dbm, secondary resistively
terminated
C. Input at 0 dbm , sec ondary res istively
terminated
d. Osc illator residual distortion
d
<I
5
6
7 89 !
' 00
FREQUE NCY IN CYCLES PER SECOND
- - - - - - UNTERMINATED
.1 1 1 11 1 1 11111~
3
5 67891
100
.:
S 67891
10000
3
':!J
50000
FREOUENCY IN CYCLES PER SECOND
DIA GRAM C - Longitudinal
Current Cancelling Characteristics of
the K-241-D
The attenuation of longitudinal currents, measured on th e 600
ohm input connection is shown in db below th e relative stea dystate transmission level.
Frequency response is guaranteed on all 20-20 plus transformers
Desc riptiv e Data
** Max . Impedance, Ohm s Primary DC MA
Level
Primary Secondary
Max.
Unba l.
Dimension s, Inches
Height
Depth
Width
Weight
Lbs.
Net
Pri ce
+ 8
500-2800
23/4
1V2
2
$30.00
Frequency response, ± 1 db : 10-25,000 cps.
Primary balanced to attenuate longitudinal
dbm
125-31 70,000***
currents in excess of 50 db . Secondary may
or
or
be used single ended or in push-pull. Has 2
600-340- 84,000 ***
secondary windings with balanced capaci150-37.5
tance to ground. Electrostatic shield is provided between primary and secondarY . .Has 90 db electromagnetic shielding. In se rtion lo ss 11/4 db.
Transformer will operate into open circuit or resistiv e load. Frequency response down less than 1 db at 15 KC , wh en operated into resistive
load shunted with 120 MMFD, capacitance . High power ratin g makes tran sformer suitable for use as output transformer.
* This t ran sformer may also be used as a bridging tra nsform er.
Complete application data in each packing box.
**Max imum operating level , 1 mw reference.
'** Impedance is total of two separate windings.
Available only tlwough autho1'ized Peerless distributors.
Since 1935, Peerless. ha s designed and manufactured transformers of hi ghest reliability to .exact specifications for electroni c application. Peerlesspionee rs in size-reduction - esta blished indu st ry sta ndard s for ru gged ness
of packaging and reliability of sea ling.
Peerless is the leader in the design and production of broa dband transformers .
Transformers engineered and built by Pee rl ess incl ude: units fro m '/8 of
a cubic inch to more than 8 cubi c feet; from fractional voltages to 30,000;
from less than one cyc le to ap proximately a half megacycle , and in one ,
two, and three-pha se or phase-changing configurations . Construction ca te·
gori es cover the entire range from open-frame construction to potted ,
hermetically-sealed and vacuum-impregnated units. Peerless transformers
ca n be varnish-treated, fosterited, epoxy or silastic-impregnated and en·
capsulated. Herm etical ly-sea led units ca n be co mpound , resin, min era l or
silicone oil-filed.
Whateve r you r transform er needs, Peerle ss eng ineers ca n design to any
give n military or comm ercial speC if ica ti ons, and manufacture in any quantity. We in vi te your inqu iries.
Divi sion of
AUDIO
•
JUNE, 1959
'11,1,1,
5
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for less work and more play
GET THE TURNTABLE
THAT CHANGES RECORDS!
...... ... .. .........................
MIRACORD XS-200
No t urnta ble and no reco rd player,
in the his tory of high fidelity, gives
yo u more quality a nd m01'e f eatures
tha n th e famous MIRACORD XS-200!
• heavyweight, professional-type tur ntable-and a fully-automatic cha nger !
• plays both stereo and monophonic!
• push-button controlled throughout!
• Magic Wand sp indles eliminate
pusher platforms and stabilizing
arms!
• intermixes 10" a nd 12"; plays a ll
4 speeds; has a 4-pole motor!
• even as a turntable it shuts off
automatically when record is
finished and tone arm returns to
rest position.
-yet it costs only
S67 5 0 audiophile
LETTERS
Hi-Fi System Hum
SIR:
The important topic of h um is again
considered, this time accidenta lly . To those
who. have checked, eliminated, r ech ecked,
r ewIr ed, and so on, until ever y method of
hum reduction h as been employed with a
l ack of suffici ent results, I suggest one
more try . A few years ago, I succeeded in
reducing the hum level within my radiophO~lO hi·fi system (wh ich is responsive
audIbly a nd technically down to 26 cps)
to a nea rly inaudible level. Receutly, however, I h ave been disturbed by a gradual
increase in the hum level. This situation
has been growing worse over the past few
months.
Last w eek, as a res ult of installing some
h eavy appliances in my home, I had my
electrical service r ewired from pole to
branch-circuit p anel. At the sam e time
the. water -pipe ground was lifted tempo:
r anly for a few days while a new location
for the ground connection was established
near the new m eter box. Simultaneously
the hum level increased significantly. Since
the water-pipe ground for the new electrical service h as been established the
a udible hum has disappeared compietely.
As a result, I should like to offer the
following a dvice : Check your water pipe
ground connection from your electric
power panel, m et er box, and so on. Make
sure that a ll connections a r e cleaned, tightened and protected from corrosion a nd
mechanical abuse. Low impedance grounds
are essential- apparently even in your
electrical service.
A. C. POFF, JR.,
6926 EI Cedral St.,
net
Long Beach 15, California .
A.C. Balance in Power Amplifier
SIR:
STEREOTWIN 200
the stereo cartridge that
ELIMINATES HUM!
STEREOTWIN is th e perfect magn etic
hi-fi car tridge for stereo and mon au ra l! It fits all record changers a nd
sta ndard tone a rms. And thanks to
sp ec ia l construction a nd MuM eta l
shielding, it e limin ates hum! Insta nt
stylus replaceme nt , too.
NOW
$4450 audiophile
net
FAR AHEAD) THE FINEST BY FAR
Available at selected dealers.
FOT Free catalogue, 1Jlease 'write D ept. A
AUDIOGERSH CORP.
514 Broadway, New York 12, N.Y. _
WORTH 6-0600
~
I should like to take exception to one
statement made by Mr. Horowitz in his
fine a rticle on push ·pull amplifiers in the
April iss ue.
A. C. balance h as proved beneficial in
cases where perfection demands distortion
at the lowest possible l evel, even with
closely m atch ed output tubes, and w ith
selected dual·triode inverters or drivers.
I can think of some h a lf-dozen highpower kit amplifiers to which balancing
arrangements h ave been added to the
phase-splitter circuit. In each case, a lower
intermodul ation and harmonic distor tion
was r ealized. Further, a ny ch ange of tubes
from the phase splitter on to t h e ou tput
stage almost a lways necessitates re-bala n cing.
To be completely objective, h owever, i n
most cases the difference, while m easura ble, cannot be detected by ear.
L. B. DALZELL,
1162 Fleetridge Drive,
San Diego 6, California.
Audio Patents
SIR:
For a long time I have intended to write
a nd tell you that I h ave m i ssed the feature
Audio Patents, by R. H . Dorf, and would
like to see it r eillstatecl.
P lease add my voice a nd vote to the
r eader who recen tly wrote to you in the
same vein .
C. E.
BEILMAN,
Argonne National Labora tory
P. O. Box 299,
Lemont, Illinois.
We miss them, too. ED.
NEW LITERATURE
• Electro-Voice, Inc., Buchanan, Mic h. ,
has just p u blish ed one of the most han dsome and worth -while high-fide lity catalogs ever to be produ ced. A comp lete ly
new a nd co lorf ul gui de to the ex t en sive
E -V line of s pea k ers, enclosures, a nd
s peaker systems, Catalog 134 also contains a we ll -written introduc tion to ster eo
so und a n d illustrates prope r placement
of speakers in stereo music systems. Irr e spective of yo u r interest in speakers
an d s p eal,er systems-whethe r lay m a n or
professional- this catalog wi ll b e a
worthy a ddition to your a udi o libl·ary.
Availab le upon written r eq uest. Specify
Catal og 1 34.
F-16
• Valor Instr1Unents, Inc., 1 32 14 Crenshaw, Gardena, Calif., has p e rform ed a
fine industry service with the publication
of "Audio Tran s istor Kinks," Vol. 1, No.
1, a four-page fo lde r covering "Vo ltage
Brealtdown a nd Leakage Curr ent in' Tran s istors." Written on a professiona l engin eering level, these a rticles have s timulated a great deal of favorab le co mm ent
so far, a nd wil l undoub ted ly be of cons iderab le inte r es t to AUDIO 's readers
who work with transistors in a ny manner.
F-17
• Jensen Manllla.cturing Company, 6601
S. Laramie Ave ., Chicago 38, Ill., fully
i llustrates and describes its new lin e of
monophonic a nd stereo spea ker syst~ms
in Catalog 16 5-C wluch w,ll be mai led
free u pon written request. Comp lete specifications of the new J ensen t ub e-vented
Bass-S u perflex e n clos u res for high-comp lia nce Flexa ir woofers are in c luded. T he
Stereo Director units which are said to
permit "aiming" of direct ional f r equ encies, thus eliminating the nee d for a ngling
cabine try, are fu lly exp la in ed. A lso illlus trated a nd described a r e the Jensen
kits for those who wish to build their
own cab inets or built-in speake r system '.
An exce llent catalog. " ' rit e for a copy.
F-JJ.8
• CBS-Hytron Adve·r tising Service, Parker
St. Newb uI'yport, Mass., will m a il free
a copy of a most interesting a rt ic le titled
"Wh y a Ceramic Cartridge '!" Written by
B ud Tom er, this 4-page folder does an exce llen t job of analyzing, the basic diffe~'­
e nces in crystal, cer anllC, and nlagnet1c
pickup s. A l tho u gh proponents .of other
types of cartridges may take issue wi~h
certa in of its con clu sions, no one WIll
deny that the a uthor presents his case
with force an d authority. Write for t h is
excellent piece of a u dio iiterat u re-;-of
inte r es t to eng in eers a nd h obbY Ists a lll, e.
F-19
• Unive.r sity Loudspeake.l 's , Inc., 80 S.
Kensico Ave., White P lai11s, N . y" h as
just i ssu ed a handsom ely-prepared 16p age book le t !,-ppropria t ely titl e ~ "An Informative GUlde to HIgh FIdelIty Stereo
a nd Monophonic Speaker Syste ms and
Compon ents." Available free upon Wl'ltten request, this book is f ull of usef ul
information, tips a nd pract ical s u ggestions of interest to everyone contemp lating bu il ding or improving a hi-fi speak e r
system. In addition, there is a co mp lete.
co n cise, i llu strat e d descripti on of every
speak er and accessory comp011ent man ufactur ed by University. Dir ect yo ur r e quest for a copy to Desk BL-l.
F-20
• The Turner Company, 909 17th St., N.E.,
Cedar Rapids, Iowa, will m a il up on r equest a new catalog on the compa ny's
entire line of microphones, sta nds, and
oth er miscellaneo u s accessories. I llu str a tions speci fi cations, a nd d escript ion of
each 'product make this publication.an excellent h andbook for the selectlOn of
microphones an d accessory eqUlpment for
a ny application. Write for it.
F-21
• Amplifier Corp. of America, TransMagnemite Divisio·n , 398 Broadway, New
York 13, N. Y., will mail wi,thout cos t a
n ew 6- page brochure descI'lbmg !n deta Il
exclu sive ITlec ha ni cal and e lectl'l.cal f eat u res of the latest Tra nsMagnemlte transis torize d, battery-operated, sprmg-m otor
portab l e tape recorder s which were en g ln eered espec ia ll y for profe~sional field
applications. Single- a nd multI-speed ,mode ls are avail ab l e and liste d With the Ir r es pe ctive record ing characteristics tab u lated fo r easy reference. T)1e r:ecorders'
oper ations are conCIsely explamed an d
compl ete technical specifi cat ions, recommended accessories, as well as dir ec t fac tory p ri ces are included.
F-22
AUDIO
6
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•
JUNE, 1959
THE PEERLESS K·241·D (20·20 Plus)
INPUT TRANSFORMER
The K-241-D is a 20-20 Plus transformer of comparatively small
size in relation to its performance characteristics. Its primary balance
places it in a class with repeating coils (See Chart C). It is magneticall y
shielded to 90 db. The following charts show its superb performance.
They demonstrate the quality of P eerless which can help
solve your input transformer problems .
~'t-~j
~}-ttj
-
DIAGRAM
r---
1 1111111111
. ..;; ....
....
111 1111111
<1
5
6
7
fRE~U EN CY
8 9
,
I
10 0
,
10 00 00
- - - - _ TERt41NATED
IN CYCLES PEA SECOND
DIA GRAM B-Harmonic Distortion K-241·D
Distort i on chara cteristics are shown und er
three conditions.
a. Input at + 8 dbm , seco ndary open circuited
,, a
\
b.
Input at + 8 dbm , secondary resistively
t ermina ted
C. Input at 0 dbm, secondary resistive ly
terminated
d. Oscillator residual di stortion
,
rI! ,
··.1•.
r--I.... ,
A-Frequency Response K·241-D
Frequency response curves for four oper·
ati ng conditions, di vided into two parts.
The first sho ws response at ma ximum
rated powe r level wit h the transformer
terminated resistively and unterm inated.
The sa me conditions of operation are
shown in the seco nd part except fo r the
- 60 dbm leve l which is rep resentati ve
of microphone output. Extreme performance
sta bi lity is illustrated by these freq uency reo
sponses taken at wi dely differe nt powe r levels and
under two extremes of operations; that is, with open cir·
cuited seconda ry and with fully loaded seco ndary . Performances
between these extr emes 'are within the illu st rated limiting curves.
-
.
a
d
<I.
5
6
7 8 9 !
100
fRE QUENCY IN CYCLES PER SECON D
- - - - - - UNTERMINATED
.1 1 1 11 1 1 11111~
3
4
3
5 6'7891
4
~
lOa
67891
10000
FREQU EN CY IN CYCL ES PE R SECON D
DIA GRAM C - longitudinal Current Cancelling Characteristics of
the K-241 -D
The atte nuati on of longitud inal currents, mea sured on the 600
ohm input connection is shown in db below the relat ive steady·
state transmission level.
Frequency response is guaranteed on all 20-20 plus transformers
Desc riptive Data
** Max . Impedance, Ohms Primary DC MA
l evel
Primary Secondary
Max .
Unbal.
Dimensio ns, Inches
Height
Depth
Width
Weight
lbs.
Net
Price
Frequency re sponse, ± 1 db : 10·25,000 cps.
+ 8
500-280·
1lf2
o
2
$30 .00
Primary balanced to attenuate longitudinal
dbm
125-31 70,000" *
cu rrents in excess of 50 db. Secondary may
or
or
be used single ended or in push·pull. Has 2
600·340· 84,000***
secondary windings with balanced capac i150·37.5
tance to grou nd. Electrostatic shield is provided between prima ry and secondar.y. Has 90 db electromagnetic sh ieldi ng. Insertion loss 11/4 db.
Transformer will operate into open circuit or resistive load. Frequency response down less than 1 db at 15 KC, when operated into resistive
load shunted with 120 MMFD , capaCitance . High power ratin g makes transformer suitable for use as output transformer.
* This tran sformer may al so be used as a bridging tra nsformer.
Complete application data in each packing box.
<* Maximum operating level , 1 mw refe rence .
*** Impedance is total of two sepa rat e wi ndings.
A vailable only tlwough autho1'ized Pee1'less dist'l'i butors.
Since 1935, Peerless. has designed and manufactured transformers of high·
est reliability to exact specifications for elect ronic application . Peerless pioneers in size·reduction - estab lished indu stry standards for rug ged ne ss
of packagi ng and reliability of sealing.
Peerless is the leader in the de sign and production of broadband tran s·
forme rs.
Transformers engineered and built by Pee rle ss inc lude : un its from '/8 of
a cubic inch to more than 8 cubic feet ; from fractional voltages to 30,000;
from less than one cycle to appro ximately a half megacycle , and in one ,
two, and three·phase or phase·changi ng confi guration s. Construc ti on cate·
gories cove r the entire range from open·frame con st ruction to potted,
herm et ically·seale d and va cuum·impregnated units. Peerless transformers
can be varnish·treated, fosterited, epoxy or si la stic·impregnated and en·
capsulated. Hermetically·sealed un its can be compound , resin, mi neral or
silicone oil ·filed.
Whateve r your transformer needs, Peerless engineers can de sign t o any
given military or comme rcial specifications, and manufactu re in any Quan·
tity. We invite your inq uiries.
Division of
AUDIO
•
JUNE, 1959
rd.III.'
5
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AmericanRadioHistory.Com
STEREO EQUIPMENT CABINET KIT
MODEL SE-1 (center unit)
Shpg. WI. 162 Ibs.
$14995
MODEL SC-1 (speaker enclosure)
Shpg. WI. 42 Ibs .
$3995 eac h
Superbl y designed cabinetry to house your complete stereo system .
Delivered with pre-cut panels to fit Heathkit AM -FM tun er ( PT-I ),
stereo preamplifier (SP-l & 2) a nd record changer (RP-3). Blank
panels also supplied to cut out for any other equipment you may now
own. Adequate space a lso provid ed for tape dec k, speakers, record
storage a nd am plifiers. Speaker wings wi ll hold He athkit SS-2 or
other speaker uni ts of simil ar size. Availab le in unfinished birch or
mahogany plywood.
MONAURAL-STEREO PREAMPLIFIER
KIT (Two Channel Mixer)
MODEL SP-2 (stereo) $56.95 Shpg. Wt. 15 Ibs.
MODEL SP-1 (monaural ) $37.95 Shpg. Wt. 131bs.
MODEL C-SP-1 (c onverts SP-1 to SP-2) $21.95
Shpg. Wt. 5 Ib s.
Special "building block" design allows you to
purchase instrument in monau ral version a nd add
stereo or second channel later if desired . The SP-I
monaural preamplifier fe atures six separate inputs
with 4 input level controls. A function se lector
switch on th e SP-2 provides two channel mixing.
A 20' remote balance control is provid ed .
HIGH FIDELITY
RECORD CHANGER KIT
MODEL RP-3
PROFESSIONAL STEREO-MONAURAL
A.M-FM TUNER KIT
MODEL PT-1
$89 96
The 10-tube FM circuit features AFC (automatic
frequency control) as well as AGC. An accurate
tuning meter operates on both AM and FM while
a 3-positj.on switch selects meter functions without
' disturbing stereo or monaur;tI listening. Individual fty'wheel tuning on both AM and FM. FM
. sensitivity is three microvolts for 30 db of quieting.
The 3-tube FM front . end is prewired and prealigned, and the entire AM circuit is on one printed
circuit board for ease of construction. Shpg. Wt.
201bs.
AUDIO
•
$64 95
Turntable qualit y wi th full y a ut o matic
features! A unique "t urntable pause" all ows
record to fall ge ntl y into pl ace wh ile turnt ab le is stopped. The tone
arm engages the motionl ess record , a nd a fri ction clutch assu res
smo oth start. Automatic speed selector plays mi xed 33 % a nd 45
RPM records rega rdless of sequence. Four speeds available : 16,33 %,
45 and 78 RPM . Changer co mplete wit h GE-VR-II cartridge wit h
di amond LP and sapphire 78 sty lus, cha nger base, sty lus pressure
ga uge and 45 RPM spindle. Shpg. Wt. 19 Ibs.
"EXTRA PERFORMANCE" 55
WATT HI-FI AMPLIFIER KIT
A rea l work ho rse packed with top qua lity
feat ures, thi s hi-fi a mplifier represents a
remarkab le val ue at less than a do ll ar per
wa tt. Full aud ifl ou tp ut at maximum
dampi ng is a true 55 wat ts fro m 20 CPS
to 20 kc with less th a n 2% tot a l harmonic
distortion throu ghout th e entire range.
Fea turing fam ous " bas-bal" circuit, pushpull E L34 tubes and new mod ern styling.
Shp g. Wt. 28 Ibs.
JUNE, 1959
MODEL W7-M
$5495
7
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HIGH FIDELITY AM TUNER KIT
MODEL BC-1 A
$26 95
Designed especially for high fidelity applications
this AM tuner will give yo u reception close to
FM. A special detector is incorporated and the
IF circuits are " broad banded" for low signal
distortion . Sensitivity and select ivity are excellent
and quiet performance is assured by a high
signal-to-noise ratio. All tunable components
are prealigned before shipment. Your "best buy"
in a n AM tuner. Shpg. WI. 9lbs.
"BOOKSHELF" 12 WATT AMPLIFIER KIT
MODEL EA-2 $28 95
There are many reasons why this attractive amplifier is such a tremendous dollar value. You get rich, full range, high fidelity sound
reproduction with low distortion and noise ... plus "modern styling".
The many features include full range frequency response 20 to 20,000
CPS ± I db with less than I % distortion over this range at full 12
watt output-its own built-in preamplifier with provision fo r three
separate inputs, mag phono, crystal phono, and tuner-RIAA equalizalion-separate bass and treble tone controls-special hum control
and it's easy-to-bui ld . Complete instructions and pictorial diagrams
show where every part goes. Cabinet shell ha s smooth leather texture
in black with inlaid gold design . Shpg. Wt. 15 lbs.
HIG H FIDELITY FM TUNER KIT
MODEL FM-3A $26 95
For noise and static-free sound reception, this FM
tuner is your least expensive source of high fi delity"material. Efficient circuit design features
stabilized oscillator circuit and broadband IF
circuits for full fidelity with high sensitivity. All
tunable components are prealigned before shipment. Edge-illuminated slide rule dial. Covers
complete F M band from 88 to 108 mc. Shpg.
Wt. 8lbs.
"UNIVERSAL" 12 WATT
AMPLIFIER KIT
MODEL UA-1
$21 95
Ideal for stereo or monaural applications, this
12-watt power package features less than 2%
total harmonic distortion throughout the entire
audio range (20 to 20,000 CPS) at full 12-watt
output. Use with preamplifier models WA-P2
or SP-I & 2. Taps for 4, 8 and 16 ohm speakers.
Shpg. Wt. 13 Ibs.
HIGH FIDELITY TAPE
RECORDER KIT
MODEL TR-1A $99 95
Includes tape deck assembly. preamp li fier and roll of tape.
MODEL TE-1
$39 95
Shpg . Wt. 10 Ibs. (Tape Preamplifier Only)
The model TR-I A provides monaural record / playback with fast
forward and rewind functions. 7Vz and 3% IPS tape speeds are
selected by changing belt drive. Flutter a nd wow are held to less than
0.35 %. Frequency response at 7V2 IPS ± 2.0 db 50-10,000 CPS , at
3% IPS ± 2.0 db 50-6,500 CPS. The model TE-I record / playback
tape preamplifier, supp lied with the mechanical assemb ly, provides
NARTB playback equalization. A two-position selector switch provides for mike or line input. Separate record and playback gain
controls. Cathode follower output. Complete instructions provid ed
for easy assembly. Signal-to-noise ratio is better than 45 db below
normal recording level with less than I % total harmonic distortion.
(Tape mechanism not sold separately) . S)1pg. Wt. 24 lbs.
8
AUDIO
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•
JUNE, 1959
CONTEMPORARY
Model CE-1 B Birch
Model CE-1 M Mahogany
CHAIRSIDE ENCLOSURE KIT
MODEL .CE-1
• No Woodworking Experience
Required For Construction.
• All Parts Precut & Predrilled
For Ease of Assembly.
• Maximum Overall Dimensions:
18" W. x 24" H. x 35)1, " D .
................................................
$.43 95·.each
Control your complete home hi- fi sys te m right from
yo ur easy chair wit h t his ha nd some chairside encl osure in either traditional or co nte mporary models. It is des igned to house th e Hea th kit A M a nd
FM tuners (BC-I A a nd FM -3A) a nd t he WA- P2
prea mplifi er, along with th e RP-3 o r majorit y of
record cha nge rs which will fit in t he space prov id ed.
WeH·.venti la ted space is provi ded in the rear of th e
encl osure for a ny of the Heath kit a mplifiers design ed to o perate with th e WA- P2 . Th e tilt- o ut
shelf ca n be installed o n eit her right o r left si de as
des ired during the co nstru cti o n, a nd the lift- to p
lid in front ca n also be reve rsed . All pa rt s a re prec ut a nd predrilled for easy asse mbl y. The conte mpora ry ca binet is ava il a bl e in either ma ho ga ny
or birch , a nd t he traditiona l cab inet is a vail a ble in
ma hoga ny suita ble for the fini sh of your ch oi ce.
All ha rdwa re supplied . Shpg. WI. 46 Ib s.
~--------=-
IT'S EASY . . . IT'S FUN
AND YOU SAVE UP TO X
WITH DO·IT·YOURSELF HEATH KITS
Pulling together your own Heathkit can be one of the most
exciting hobbies you ever enjoyed. Simple step-by-step instructions and large pictorial diagrams show you where '
every part goes. You can't possibly go wrong. No previous
electronic or kit building experience is required. You ' ll
learn a lot about your equipment as you build it, and , of
course , you will experience the pride and satisfaction of
having done it yourself.
LEGATO HI·FI SPEAKER SYST EM KIT
MODEL HH-1
"RANGE EXTENDING" HI·FI
SPEAKER SYSTEM KIT
The SS-I B employs a 15" woofer a nd super
tweeter to extend overall response of bas ic
SS-2 speaker from 35 to 16,000 CPS ± 5 db.
Crossover circuit is built in. Imped a nce is 16
ohms, power ra ting 35 watts. Constructed of
3f.I " veneer-surfaced plywood suit a bl e for li ght
or dark fini sh. Shpg. Wt . 80 Ibs.
$299 95
The sta rtling rea li sm of sound
duction by th e Lega to is
t hr ough t he use of two 15" Altec
Lansing low frequen cy d rivers and a
specia ll y designed ex ponenti al horn
with high frequ ency driver. Th e speci al
crossover networ k is buil t in . Covers
25 to 20,000 CPS within ± 5 db. Power
ra ting 50 wa tts. Ca binet is constructed
of 3f.I " veneer- surfaced pl ywood in
either Africa n ma ho ga ny o r white
birch suitable for t he finish of your
cho ice. All pa rts a re precu t a nd predrilled fo r easy asse mbly. Shpg. WI.
1951bs.
CO M PANY' BENTON HARBOR 25, MICH .
U~bSidiary of Daystrom, Inc.
o
~re"~~~e~n~ro~: pcisiage
Please se nd t he Free Heathkit cata log,
. :'n~a.'..'m'."e'---_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __
for parcel post- ex press
orde rs are shi pped de·
~,r~i C~~ar~.sB. CS~~~;~
a .::d.::d!::
~
re:.::s~s_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __
Harbo r, Mi ch . A 20% de·
pos i t is requi red on al l
;~~e~t t~r~~~~'g:~ft~~
out notice .
AUDIO •
cci'ty
.:~&'-'s:..'t.':at:e:'---_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __
-
9
JUNE. 1959
www.americanradiohistory.com
AmericanRadioHistory.Com
achieve even more extreme hi-fi miniatlll'i·
zation.
.
A p ail' of Regencies will tit nicely 1I1tO
an odd com er of a ny hi-fi. system, on top
or to one side of other equipment, with a
minimum of cables; there ar e cork composition feet on the bottom corners to anchor
the unit and minimize' scratches. They're
only stuck on, with rubber cement, bnt
they work. Why noH
A r emovable back plate with two screws
allows for battery changing and the uuit
will operate eithe: on one o~· two 9-volt
batteries-same life but hIgher sound
quality with 18 vO.lts .. This w.o uld seem to
be an inherent chOIce III t r anSIstor batterypowered equipment and it represents. a
good value, too, since you may economIze
with only one battery (they cost plenty of
cash ) or, in an emergency,. make use of one
when a second isn't avaIlable. The relatively large-capacity batteries t1~at were
for several hours. A few days later I did
fumished by Regency were a good Idea, but
it again, though I had told myse.lf I just
when I tried to r eplace them I found th at
wouldn't. That time it was overUlght. The
one New York supplier didn't carry t~e
end came quickly, alas, w heu I set .off for
type. Not important, since battery aVaIlthe countl'y the same week~nd lea:vmg the
abilities vary from place to place; I put
little darlings happily burnmg the11' hearts
in a common bnt smaller type, Burgess
(batteries) out. When I got back, on blue
2U6 which worked out fine. There's room
Monday, they were dead, very dead.
.
for 'various types and sizes, in case of
But before I give you my answer to tlll S
necessity.
life-and-death problem in Regency'~ J:I~'r­
As to sound, the Regency preamp ~o e.s,
lA, let me descl'ibe the ].:ll'eamps hVlllg
to be sure, prodnce th3;t charactens.tlC
virtues, given fresh battenes.
.
slight hiss, at higher gam l evel~, whIch
The HFT-1A is a neat oblong measul'lng
seems to be inevitable in all-transIstor deonly about seven by two by three inche~,
sign at t his stage. Here, you trade hu.m
add a quarter-inch or so each way. It I S
for hiss and , when yo u come down to It,
black with a handsome gold front pauel
I prefer a bit of. hiss an;r day . . Not obtr?-and four round, black control knobs, leg- sive mind yo u-Just a bIt of It, clown ill
ibly marked SELECTOR, BASS, TRE- the tube-noise area.
BLE, LEVEL, garlands of numbers enAs a comparison, I tried one Regency
circling the last three, zero at the top.
prcamp hooked into one ha~f of a stereo
(One curious thing is that the "fla~" posiset-up, the other channel g01l1g through. a
tion is not exactly at the zero pomt but
Dynakit preamp, both set at RIAA WIth
slightly off to one side-which is just plain
the tone contI'ols flat. ( The Regency, by
nutty and surely unnecessary. But the disthe way has all the gain yo u can possibly
placement is slight enough so ;ron can
want a~d, indeed, it had more gain by a
ignore it in practice and, at this stage,
good deal than the corresponding input
I've ah eady forgotten the precise "flat"
channel on my dual-12-watt stereo amplipoints.) The SELECTOR knob has foul'
fier of standard tube design.) Now here r
positions, rather faintly marked MAG
uoticed at once, I must admit, that the
PHONO, MIC, TUNER, XTAL PHONO .
tonal balance on this direct comparison of
What~ No RIAA, AES, 78, COL, LP,
two stereo channels was not exactly the
LON, etc. , Nope ! Not a trace of 'em, and
same through the two preamps-RIAA or
I thoroughly approve. This is a good ex110. (B ut I would be hard put to it to
ample of the latest trend in the old busichoose which seemed "righter"). They were
ness of record equalization and it was
slightly clifferent, and that was that.
surely inevitable, once the dismal tanglc
of some years back was ironed out in favor
of near-conformity, around RIAA.
Tolerances
I've always felt that eventually we woulcl
have on most equipment just the one equalWhich I think, merely offers a slightly
ization position-moI'e accurate, none at
r ealistic proof of the principle, usually le~t
all with RIAA taken for granted and
unmentioned, of allowable tol erances III
built-in. That's what we have in Regency's
good audio design. Nobody matches the
preamp, and I remind you that most ,:,ariaRIAA curve exaotly, without some leeway.
tion8 in the old r ecord curves can stIll be
Maybe nobody ever has_ Every audio man,
ta ken care of via the average bass and
every manufacturer, knows perfectly well
treble controls-and that, too, within quite
that those little works "plus-or-minus"
small tolerances, as was pointed out long
mean what they say, and in every audio
yeaI's ago by engineer Howard Sterling in
component, too.
connection with his Electronic Workshop
Perhaps the toleran~es in match i~g the
and Waveforms amplifier lines.
ideal RIAA curve (whICh, I gather, IS supThe real' of the Regency is neatly ar- posed to be designed for fairly easy matchl'anged, with foul' input sockets at the
ing via common component values) are not
usual right end of the panel (as yon look
quite as close in general practice as, say,
at t he back ) and a single ma;n output
the much-advertised tolerances for over-all
socket at the other end, well isolated.
amplifier response, distortion and so OIl. I
Good: too many preamps mix the inputs
wouldn't know. But I strongly suspect that
and outputs together, inviting all sorts of
in much of our present audio equipment,
wrong connections.
including the best, equalization tolerances
In operation, the little preamp is easy
are wide enough so that if two unlike
and convenient to use (not counting that
models of different make happen to hit the
fatal lack of an 0:-< signal) . The unit is just
opposite extI'emes within their r espective
heavy enough so t hat yon can work it with
tolerance limits, the r esulting sounds on
one hand, without slippage. Note that many
direot oompa7'ison could be noticeably difsmall units of this sort are so light in
ferent, taken from the standard RIAA
weight that, paradoxically, you must use
control settings. Nothing for us to be
both hands in order to operate the conashamed about, I'd guess; nor could I put
bla.me either on Dyna or Regency in this
trols. A thought, here, fo r those who would
Ere
edward TatnaliCanby
A Pilot for Regency
1. THE RECENCY HFT-1A
I've been playing with a pair of lovely
little all-transistor preamplifiers lately_ And
as a result, I've been fussing with a problem in pilot lights_
Except for the glaring lack of this last
commodity the Regency HFT-1A batterypowered Pre-Amplifier (Regency's spelling) is a pleasure to use and a doublepleasure; more or less, in a pair for steroo_
A pleasure for me, that is, until I ran the
batteries dead, which was all too soon_
More of this later_
'1'ransistor audio, especially the all-transistor sort, has been exel·ting a lot of fascination upon audiofans this last year.
There is the newness of the Cil'cuitry, of
course. But more important are t he new
factors of miniature size, extraordin arily
low current drain and the convenience of
low-impedance inputs that allow the transistor preamp to be used in place of a
transformer for low-impedance broadcasttype mikes (with long cables) and for magnetic phono cartridges. Also of interest is
the battery-type operation and the new
applications for portable, non-power-line
hi-fi, often possible from an auto battery.
Last year, the Vico all-transistor complete
hi-fi amplifiers brought more inquiries to
this department than anything I had mentioned in many a month, though the company later got into a snarl of some sort and
gave Up.I
I first got interested in transistor hi-fi
thanks to the pioneer Fisher all-transistor
preamp of a few years back, a small battery-operated unit that nnexpectedly went
to work as an emergency mike preamplifier
fol' my broadcast tape set-up and managed
to last a whole season on the original bat·
tery, pending the completion of my permanent equipment. The new Regency preamp
is its latest descendent and it is a "complete" unit, with phono equalization, bass
and treble controls, function switch, all
operated in a very small space from builtin batteries. I was delighted at the compactness, good looks and the easily managed multiple functions that have been
incorporated into this small unit and my
only beef, a great big one, is that the
Regency doesn't tell you when it is turned
on. Not so you'd notice it, anyhow. For
this, h owever, I have found a dramatie
solution, not envi sioned by Regency.
You see, the very first day I got th ese
two preamps I inadvertently left them on
1 '1'he Vico line is being r eorgauized, the
entire inveutory having been sold out by its
origiuator, Video Instruments. A new corporation was being form ed to take over
the line and the interim management was
by the Altshuler Managemeut Co., 1555
Nor th Bronson Av., Los Angeles 28, Calif.
Further information will be forthcoming
from them, when & if.
' AUDIO
10
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•
JUNE, 1959
NEW STEREOPHONIC EQUIPMENT
HF85: Stereo Dual Preamplifier is a complete stereo con·
t rol sys t em in " lo w silhouett e" des ign adaptable to any
t ype of inst allation. Selecl s, preamplifie s, controls any
st er eo source - tape , discs , broadcasts. Superb variable
cro ssov er, fe edback ton e controls driven by feedback
amplifi er pair s in each ch annel. Distortion borders on
unmeasurabl e ev en at high output levels . Separate 10'
level input in each chann el for ma g. phono, tape head,
mike. Separat e hi-level inputs for AM & FM tun ers & FM
Multipl ex. On e each auxiliary A & B input in each channel.
Independ ent level, bas s & treble controls in each channel
may be operat ed tog eth er with built-in clutch . Switchedin loudn ess compens ator. Function Selector permits hear·
ing each st ereo channel individually, and reversing them;
also use of unit for ster eo or monophonic play. FUll-wave
re ctifi er tub e power supply. 5-12AX7 / ECC83, 1-6X4. Works
w ith an y hi gh-quality st ereo power amplifier such as
EICO HF86, or any 2 hi gh-quality mono power amplifiers
su ch as EICO Hf14, HF22, HF30, HF35, HF50 , HF60.
" Extreme flexibility . . _ a bargain" - HI -FI REVIEW.
Kit $39.95 . Wired $64.95. Includes cover.
AND
MONAURAL
HF86: Stereo Dual Power Amplifier for use with HF85
above or any good self-power ed stereo preamp. Identical
Wi lliam son -typ e push -pull EL84 power amplifiers , conse rvativ ely rat ed at 14W, may be operated in parallel to
de liver 28W for non-stereo use . Either input can be made
common for both amplifiers by Service Selector switch .
Voltage amplifier & split-load phase inverter circuitry
featur e EICO -developed 12DW7 audio tube for significantly
bett er performance . Kit $43.95 . Wired $74.95.
HF81: Stereo Dual Amplifier-Preamplifier selects, amplif ies & control s any stereo source - tape , discs, broadcasts-& f ee ds it thru self-contained dual 14W amplifiers
t o a pair of speakers. Monophonically: 28 walts for your
speakers: complete stereo preamp . Ganged level controls,
separat e focus (balance) control , independent full-range
bass & tr eble controls for each channel. Identical Williamson-type, pu sh-pull EL84 power amplifiers, excellent output tran sform ers . "Service Sel ector" switch permits one
pr eamp-control section to drive the internal power amplifiers whil e other preamp-control section is left free to
drive your eXisting external amplifier. "Excellent" SATURDAY REVIEW; HI-FI MUSIC AT HOME . "Outstanding quality ... extremely versatile" - RADIO & TV NEWS
LAB-TESTED . Kit $69.95 . Wired $109.95. Includes cover.
MONO PREAMPLIFIERS (stack 2 for Stereo) HF-65: superb
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$33.95. Wired $49 .95 _
MONO POWER AMPLIFIERS
(use 2 for STEREO)
HF60 (60W), HF50 (50W), HF35 (35W) , HF30 (30Wl, HF22
(2 2W), HFI4 (14W): from Kit $23 .50. Wired $41.50 _
MONO INTEGRATED AMPLIFIERS
(use 2 for STEREO)
HF52 (50W), HF32 (30Wl. HF20 (20W), HF12 (12W): from
Kit $34.95 _ Wired $57.95.
SPEAKER SYSTEMS (use 2 for STEREO)
HFS2 : Natural bass 30-200 cps via slot-loaded 12-ft. split
conical bas s horn . Middle s & lower highs: front radiation
from 8'/2" ed ge-damped cone. Di stortionle ss spike-shaped
super-tweeter radiates omni-directionallv. Flat 45-20,000
cps , useful 30·40,000 cps . 16 ohms . HWD 36" . 151/4" ,
111/2 ". "Eminently musical"-Holt, HIGH FIDELITY. "Fine
for stereo"-MODERN HI-FI. Completely factory-built :
Mahogany or Walnut, $139.95; Blonde, $144.95 _
HFS1: Bookshelf Speaker System, complete with factorybuilt cabinet. Jensen 8" woofer, matching Jensen compression-driver exponential horn tweeter. Smooth clean
bass: criso extended highs. 70-12 ,000 cps range .
Capacity 25 w. 8 ohms. HWD: 11 " x 23" x 9". Wiring
tim e 15 min. Price $39 ..95 _
FM Tuner HFT90
AM Tuner HFT94
FM TUNER HFT90: For the first time , makes practical
even for the novice the building of an FM tuner kit equal
to really good factory-wired units . No instruments
. needed. Pre-wired, pre-aligned temperature-compensated
"front end " is drift free - eliminates need for AFC. Precision lCeye-tronic" OM-70 traveling tuning indicator, supplied pre-wired, contracts at exact center of each FM
channel. Pre-aligned IF coils. Sensitivity 6X that of other
kit tuners : 1.5 uv for 20 db quieting, 2.5 uv for 30 db
quieting, full limiting from 25 uv. IF bandwidth 260 kc
at 6 db points. Frequency response uniform 20-20,000
cps :!: I db. Has 2 output jacks: cathode follower output
to amplifier, plus Multiplex output for FM Multiplex
Stereo adapter; thus prevents obsolescence. Flywheel
tuning, AGC, stabilized low limiting threshold for excellent performance from weaker Signals , broadband ratio
detector for improved capture ratio & easier tuning , fullwave rectifier & heavy filtering, very low distortion .
"One of the best buys you can get in high fidelity kits"
- AUDIOCRAFT. Kit $39.95'_ Wired $65.95'_ Cover $3.95.
' Less Cover, F.E.T. incl.
Stereo
Amplifler·Preamp
HF81
Bookshelf
Speaker System
HFSI
Monaural Preamplifiers:
HF65 , HF65A
(stack 2 for Stereo)
Omni·directional
Speaker System HFS2
151/4" W x llW'
36" H x
0
A-6
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I Send FREE catalog & name of neighbor-
Monaural Power Amplifi ers :
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(use 2 for Stereo)
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l ~~~~~~:s·: :.: : .: : : : ~~~·~.• ..<••~;~~~...: : : : :~ J
hood EICO dealer.
In New York hear "The EICO Stereo Hour," WBAI-FM,
•
.~
NEW AM TUNER HFT94: Matches HFT90. Selects "hi-fi"
wide (20c - 9kc @ -3 db ) or weak-station narrow
(20c - 5kc @ -3 db) bandpass . Tuned RF stage for high
selectivity & sensitivity: precision jfeye-t~onicll t~~i~g .
Built-in ferrite loop , prealigned RF & IF COils. Sensitivity
3 uv @ 30 % mod. for 1.0 V out, 20 db SIN . Very low
noise & distortion. Hlgh-Q 10 kc whistle filter.
Kit $39.95. Wired $69.95, incl. Cover & F.E.T.
EICO, 33 -00 Northern Blvd., L_I.C_ 1, N.Y_
AUDIO
.
;
99.5
me, Mondays, Thursdays and Saturdays,
7:00
P.M.
11
JUNE, 1959
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..
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particular comparison of miue. The difference was within my tolerance .
If you use a pair of identical Regency
preamps (or a pair of Dynakits) for
steI'eo, these minute differences will never
show up at all. They didn't in my pair of
pairs.
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But now we come to the big joker in the
Regency Pre-Amplifier-and in virtually
every other battery-operated transistor device in the audio field. (That's why I'm
making a big point of it here.) How can
you tell when the thing is on' How can
you prevent aceidental extin~tion of the
expensive batteries inside '
You see, this is one of those petty, external problems that just don't get attended to properly by engineer designers,
who have their hands terribly full with
weightier matters of transistor circuitI·y,
space constriction and what-not. But for
ye doughty consnmer, this is the top-rat·
ing problem-if his batteries go dead bv
mistake. No two ways aboutdhat: ask tl;e
man who'd had it happen to him. Me, for
instance.
I don't need to go into the practical
difficulties involved in figuring out a really
visible mechanical ON signal for such devices. The problem was a familiar one in
the old portable radios, long before transistors. Various mechanical possibilities
were tried ont with greater or lesser ingenuity; some makers clearly had this on
their minds more than others. Some of the
old radios said "on" to you in very small
letters, or none at all. Others politely
waved neat little red flags. Not bad .
But the tiny transistor radios have just
about given up on this sc<?re, and most of
us have had to accept battery loss as one
of the inevitable risks of portable minia'
ture equipment. Nothing can be done, we
say, and shrug it off- until the next transistor battery goes dead.
Now in hi-fi equipment the situation
isn't quite as simple, nor can we shrug quite
so easily. Our standards for hi-fi operation
are definitely higher and more exacting, for
one thing, and that includes reliability of
operation-over a long time. There isn't a
one of us who won't be violently annoyed
if a transistor preamplifier goes dead on
us just when we want it, thereby knocking
our entire hi-fi system out of service.
In the home, where the rest of our equipment ordiuarily runs on 117 volts and is
good for indefinitely long use, such a failure of crucial equipment can be particularly infuriating. Even in the SOl·t of portable, outdoor, camp-style use that is the
special strong point of transistor hi-fi, bat·
tery failure by accident is ellough to make
anybody curse and swear. It's just too
much to take, especially when the fault is
your own. Phooey! is the mildest term
likely to be emanated, and Regency would
do well to cock its mental ear and shiver
at the mere thought of stronger language.
For these reasons, you would think, any
battery-operated hi-Ii component (not to
mention small radios and the like) would
be designed at the least for maximum visibility of whatever ON indicator is practical
under the circumstances. Even if you can't
do more than mark the ON-OFF switch,
yon can make the indication as visible as
possible, especially if your ON switch is
incorporated in the volume control, as in
the Regency preamplifier.
Dead or Alive
But the Regency people evidently had
their minds elsewh~re . Their little preamp,
so neatly and senSIbly turned out in other
respects, is a real booby trap for the ac-
12
cident-prone operator with his mind on
other matters (music, for instance) . Indeed, the combination of factors that ask
for accidental running-down of the batteries is quite uncanny. As I say, I was
caught t hree times and struck out, cold.
A. The ON switch is on the level control,
a round knob with a very small white dot
that in normal use appears at a great variety of positions, rather than one standard
and instantly visible ON location, to catch
the eye.
B. This black knob, with the too-small
white dot, is right alongside three othel'
identical black knobs with small dots, all
of which are constantly variable in their
positions. Nice to look at- but your eyes
haven't a chance of noticing the special
position of that tiny, CRUCIAL white dot
on the right knob that indicates ON, via
the volume control.
C. Finally, it just happens that the
switched volume control used on this Regency preamp is one of those that rotate
almost all the way around at the e~:tremes
of its turn. The OFF position is at roughly
half past six; the ON position when the
volume is fully rotated is half past five.
Much too close~or CQlI!fort and your eye
is very unlikely to notice the small difference at all. Mine didn't.
So, you see, in order to ensure, as ·the
British say, that the preamp gets turned
off every time, you really must have a
check list and a co-pilot to read the items
off for you, each time you cease playing
your hi-fi! With the best will in the world,
I couldn't make my pair of Regencies last
more than a week-and the four new batteries cost me money that wasn't pleasant
spending.
The simplest sort of solution for this
problem is, obviously, to put maximum
common sense and ingenuity into designing visible ON-OFF positions that are as
blatantly clear as possible, so that your eye
is caught even when you are at your most
absent-minded peak of non-attention. Not
easy, but something can be done, even
without special gadgets. Simply use clear
marking.
Beyond that, you could try again to work
out some ingenious mechanical signal of
the "red flag" sort which appears when the
unit is turned on, disappears when it is
off. Every good reason for doiug so.
Don't forget that when a battery oper ated unit is used with other equipmentas here- each section must be turned off
independently. That was my primary trouble. After years of habit-forming masterswitch operation, I just didn't remember
to turn off my 117 volt equipment and
then turn off each of the preamps, separately. Thus for hi-fi equipment of this
battery sort you need much more, a really
drastic ON signal, an indicator that positively yells at you, so to speak.
In fact, what you need, obviously, is a
pilot light. Of course ! N atch! What else!
And there, friends, is the big question that
struck me. Why not a pilot light'?
Let's Add a Pilot Light
Now there must be something wrong
here. You CAN'T add a pilot light. If you
could, somebody-everybody-would ha,e
done so, long since. Pilot lights just aren't
p ractical in battery operation. They are
fine when the cur rent source is 117 volts
from the power line. Nobody, but nobody,
would be foolish enough to think that a
pilot light on a battery would make sense.
Nobody but me, anyhow.
You see, I 'm an obstinate cuss wheu I
get annoyed. I won't take no for an answer
until I get pushed real hard .
When these two neat little Regency pre(Continued on page 46)
AUDIO
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•
JUNE, 1959
PRESENTING THE JBL RANGER·MINIGON
DESIGNS NEW
PRECISION
LOUDSPEAKERS
FOR SMALL
ENCLOSURES
PRESENTING THE JBL L1NEAR·EFFICIENCY SPEAKER
You see an all-new precision transducer that coul~ only be a product of James B.
lansing Sound, Inc. The company which brings you the best speakers for horn enclosures and the best units for reflex enclosures now offers the finest infinite baffle type
transducers. Undef intensive development for a year and a half, design judgment and
engineering decisions were recurrently confirmed by analog computer. You will hear
big, deep, accurate bass from these instruments. Application of new principles of
cone suspension permits unusually long linear excursion. Relatively high efficiency
with its attendant precision transient response, clean reproduction, vast dynamic
range is achieved by use of large voice coils, precision-instrument tolerances, advanced magnetic circuitry ~ all typical of JBl transducers_
, ,.
.
f.!
Write for a complete d escription of these new units and the name
of the Autho"rized JBL 'Signature
Audio Specialist in your community.
,
,
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EDITOR'S REVIEW
STEREO QUALITY
of opinion as to the
quality of stereo records, and of stereo repr~duc­
tion in general. While many listeners are relatIvely
well satisfied, some of the hypercritical ones complain
loudly that stereo records do not compare in quality
with the monophonic LP's. Still others-and some of
the same ones-insist that no stereo effect is discernible
in their listening rooms.
We must admit that not all stereo records are
superlative, but we hasten to add that not all LP 's
were out of this world either. All the way from the
orig'inal scheduling of a recording date to the issuance
of pres sings there are many things that can go wrong
-careless or inadequately rehearsed playing, improper microphone placement, faulty tape recording,
faulty transferring to master disc, trouble in processing, trouble in pressing, poor handling and packing,
and on and on and on. Any recording is subject to
most of the same faults-stereo or monophonic-and
the one most likely to appear only in stereo work is
the matter of microphone placement. There are many
ways in which microphones may be distributed about
an orchestra, and the techniques are certainly not yet
reduced to a cut and dried process. It is still pretty
much cut and try.
But there is also the matter of equipment andand don't forget it for a moment-the matter of
phasing. Some months ago we were invited to the
studios of a r ecord company to hear the tapes of a
new recording. Before going into the listening room,
we were told that one of the speakers wasn't right,
and would we overlook it.
We listened for eight bars, concluded that the
speakers were out of phase, and asked to have the
music stopped. Thirty seconds with a screwdriver to
reverse one pair of wires and the "speaker" was all
right again, and the tapes sounded fine.
If it is possible for those who work with music
regularly-and in this case the same ones who made
the original recording-to hear a playback in which
one speaker is out of phase and not know what is
wrong, think how much more likely the average listener is to encounter the same difficulty. Stereo reproduction can sound horrible-or at least it can lose all
the quality it should have- if the speakers are not
phased properly. And placement in the room is also
important. Quite a bit of experimenting may be foun!i
necessary before one reaches the best quality and the
optimum in stereo that he has a right to expect. After
that, the excellent records will sound superb, and the
mediocre and poor ones will sound mediocre or poor
-at least it will be possible to judge records from that
time on.
We will agree that a stereo system is more critical
to set up and get working to the listener 's complete
satisfaction than any single-channel outfit. But in all
T
HERE IS QUITE A DIFFERENCE
fairness , remember how long and hard yon worked to
get your first monophonic system p erforming the way
you wanted it to. And by the same token, r emember
that early LP's weren't all perfect either.
From our own observations, much of the cause for
complaint arises from listening to pseudo-high-fidelity
merchandise with which the market is flooded. People
who have heard about stereo and have gone to their
local appliance outlets and listened to some of the
merchandise offered under the label " high fidelity"
have found little to get excited about.
Two six-inch speakers 24 inches apart can never
approach satisfactory stereo quality, nor will an assortment of oversized TV-quality speaker units in halfinch plywood cabinets come anywher e near to good
musical r eproduction. Even if you are not in the
market for a top-quality component stereo installation,
at least take the trouble to condition your ears to
what a good system can sound like, even if you must
stick to a budget figure below what you would like.
But judging the whole field of stereo r ecords on equipment that in itself is far from perfect is like deciding
that automobiles are no good because you have just
taken a ride in a 1924 Maxwell and been less than
enthralled.
Not everyone needs a Rolls Royce, but make sure by
trying a ride in one before you make up your mind.
FOUR-TRACK TAPE
Nearly a year ago we read considerable pUblicity
about a four-track tape cartridge operating at 3% ips
which was expected by its originators to revolutionize
the tape-playback industry, but the machines failed to
reach the market. However, the four-track idea has
caught on, and performance at 71/2 ips has proved
excellent on most of those machines so far introduced,
comparing quite favorably with two-track models with
respect to both quality and signal-to-noise ratio. Undoubtedly much of the improvement in p erformance is
the result of improved heads, which might possibly
have made the two-track 71j2:ips tape comparable with
professional single-track 15-ips tape.
Herbert L. Brown, vice-president and manager of
Ampex Audio, Inc., and recently elected president of
the Magnetic Recording Industry Association, announced on May 20 that producers of r ecorded tapes
had joined together to launch a wave of four-track
stereo entertainment, and that at least 150 r eleases of
the new tape would be forthcoming within the next
few weeks.
With a number of machines available on which to
play the new four-track recorded tapes, it seems likely
that magnetic tape will quickly regain the position it
held before the introduction of the !';tereo disc. While
71/2-ips stereo tape is better than discs, in general. it
did not compare in price on a two-t r ack basis. With
four tracks it does.
14
AUDIO
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AmericanRadioHistory.Com
•
JUNE, 1959
__
·.._..........
................
_._-_ _. - --. _..._..................................... _......__ __.-..........._............. _....... _...._-------_ ._...... _............_._._--..
..
The responsibility of being the finest ...
A LIFETIME
FLUXVALVE AND T·GUARD ARE TRA OEM A RI<,S U S ED TO D E NOTE THE QU ALIT Y OF P IC K ERING 8:: C OMP A N Y INVENTI ONS .
Tru Iy the fi nest"stere0 piekupevermade .. ;
the STANTON Stereo FLUXVALVE is
hermetically sealed in lifetime polystyrene with
all of the precision that has made Pickering
a quality leader in the field of high fidelity
for more than a dozen years.
For instance ... only the
STANTON Stereo FLUXVALVE has the
"T-GUARD" stylus assembly-so safe and easy
to handle ... so obedient and responsive
to every musical nuance in the stereo groove.
237 1 A
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Stereo FLUXVALVE reproduces music
with magnificent sound quality ... from both
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I
n plain truth ... the STANTON
Stereo FLUXVALVE is by far the finest stereo
pickup made .. _backed by a Lifetime Warranty~: ,
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Only the STANTON Stereo FLUXVALVE has
We suggest you visit your Pickering Dealer soon
.
'- drop in and ask for a personal demonstration.
the parallel reproducing element contained in the
''I-GUARD''. _. assuring the proper angle of
NEWLY REVISED-HIT TAKE S TWO TO STEREO" -ADDRESS DEPT. 8 .. 69 FOR YOUR FREE COPY.
correspondence between recording and playback
styli for maximum Vertical Tracking Accuracy.
·Excludina wear and tear of the diamond stylus tip and parts
of the related moving system In the "r·GUARD" assembly.
AUDIO
•
--'"
®
- ~C ~
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lor Ihose who con~ !he tltllerMce . ".. 0.' "'' . ...
".,,'" POo••m • •
PICKERING & COMPANY, INC., Plainview, N. Y.
15
JUNE, 1959
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AmericanRadioHistory.Com
~~No
man
can improve
an original invention
• • •
- William Blake
THERE are many scientists today who would
argue this point with Blake.
At Bell Telephone Laborat6 ries, for example,
we have seen original inventions improved
and re-improved countless times, the better
to serve mankind.
But William Blake went on to say" .. .
nor can an original invention exist without
execution organized, delineated and
articulated. " Here Blake expressed ideas
that apply with striking emphasis today.
At Bell Laboratories organized effort is
constantly aimed at fostering an
environment in which inventions can exist
and prosper, where they can be
expressed either as ideas or in physical
form, and where clear understanding
of their principles can be achieved.
By helping scientists and engineers to
reach for the things they seek, by
organ izing and coordinating their efforts,
Bell Laboratories has made important
con triJJlltions to the art of communications:
proof of the wave nature of the electron,
first research in radio astronomy , discovery of
the transis tor principle, invention of the
feedback amplifier. Such ventures into the
unknown have twice brought the Nobel Prize to
Bell Laboratories scientists, and at the same time
have helped create the most efficient and versatile
telephone system ever known.
William Blake (1757-1827), a versatile genius, was
famous for brilliant, sometimes prophetic, insights which
he expressed with provocative beauty in drawing, painting, poetry and prose.
BE LL T E L EPHONE L ABORATORIES
WORLD CENT ER OF COMMUN ICATIONS RESEARCH AND D EVELOPMENT
www.americanradiohistory.com
AmericanRadioHistory.Com
"
The TW/PA2-A Comprehensive
Tape Preamplifier
ARTHUR W. WAYN E':'
For high-quality reproduction from tape, the amplifier must be designed
for the job. Simplicity does not always produce the desired results, and
most stereo preamps are complex, though not necessarily complicated.
T
excellent p r ofessional
tape preamplifiers on the market,
particularly in U.S.A., but, unfortunately, the circuitry of most of them
is rather beyond the capabilities of the
average hi-fi enthusiast. On the other
hand, the number of simple-to-make circuits must be legion; but so also must be
the number of disappointed amateur
builders. This is not to say that the designers of the simple circuits do not
know what they are doing-it is merely
that the comparatively complicated professional amplifier is, usually, the end
product of an intensive development
project, while the simple do-it-yourself
affair is more likely to be the result of
a one- or two-of construction. The chief
difference is dictated by the professional's basic necessity to make a profit
in a highly technical atmosphere, as
compared to the somewhat less strenuous
HERE ARE MANY
* Shil'ley Labomtories Ltd., 3 Pl'ospeot
Plaoe, Worthing, Sussex, England.
1 FS 100 in U.S.A.
demands of the man who likes to make will be given later. The l'ecording amplithings. However, it is sometimes possible fier is in three stages, comprising a Multo combine the advantages of both lard EF86 microphone and low-level
worlds, and the preamplifier to be de- p ickup preamplifier , and the two halves
scribed, the Shirley Laboratories Ltd. of a Mullard ECC81 double triode as the
type TW IPA21, while being a really main amplifier. Auxiliaries included durprofessional piece of equipment, is not ing the recording function are a sustoo difficult to make, needing, mostly tained peak-indicating voltmeter of conpatience and a delicate touch with the ventional design, and, of comse, a bias
soldering iron. It. is a design which has and erase oscillator. On replay, an EF86
been on the market for some while, and is the head preamplifier, with another
was originally evolved as the basic unit EF86, triode-connected, as the second
in a very exacting set-up indeed.
stage. The separation of the record from
From the schematic, Fig. 1, it will be the replay section permits, with threeseen that the recording amplifier is en- head decks, continuous monitoring durtirely separate from the replay pream- ing r ecording. Letters and figures in the
p lifier, this arrangement removing, at schematic refer to the tag-strips on the
one stroke, what is probably the most underside of the Ferrograph deck, condifficult part of tape amplifier construc- nection and switching details of which
tion, the involved switching required are shown in Fig. 2.
when the tubes are used for more than
Circuitry
one function . As shown, the circuit is
The circuit will now be considered in
arranged for use with the Ferrograph
"A" and "E" decks, but details for cou- . more detail. J1 is an ordinary singlep ling to almost any other type of deck circuit telephone jack, and can quite
PLAYBACK
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ITALIC NUMBERS REFER TO TERMINA L BOAR D, FIG. 8
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Fig . 1. Over-all sch e matic of th e author' s amplifi e r.
AUDIO
•
17
JUNE, 1959
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Fig. 2 . Connection and switching detail s of Fe rrog raph 3A tape deck.
satisfactorily be replaced by an RCAtype phono jack. The value of R l , VI
grid leak, is chosen as a reasonable
compromise for loading most types of
microphone; and there is no r eason why
it should not be replaced by a resistor of
lower value, if preferred, although users
of crystal microphones should be warned
that, with certain individual tubes,
higher values may result in excessive
grid current. When the signal source is
a pickup, equalization and the termination load must be provided prior to the
input. Rl and R2 are low-noise highstability resistors, and Gl grid 2 decoupling capacitor, can be increased to
0.1 /J-f with a slight improvement in bass
response. This increase has not been
found necessary in the commercial versions of the amplifier. Coupling capacitor G2 is chosen to give, with P 1J
almost unity coupling down to 50 cps,
and departures from this condition,
which may be necessitated by excessive
bass content in the input signal to J1,
can be calculated quite easily from the
formula R 2/ V R 2 + X 2 where X = reactance of the coupling capacitor in ohms
at the significant frequency fo) R = P"
and R / V R 2 + X 2 = fraction of f 0 passed
to the top of R via G• .
J 2 ) the high-level input, for crystal
p ickups and radio tuners, is a standard
two-circuit telephone jack, and insertion
of the plug disconnects the whole of the
low-level section from the rest of the
amplifier. A phono jack may be used in
tills position, too, but if it is, care must
be taken to ensure that only low-imped-
ance sources are put across its t erminals,
or noise from the preceding stage may
appear in addition to the signal. P l ) the
RECORD gain control, is connected via its
slider to the grid of V u) half of an
ECC81. It will be noticed that R a) the
cathode resistor for this tube, is quite
low in value as compared to R 6 ) the
provide the usual recording tl·eble lift,
and although the circuit seems too simple to be effective, it does in fact work
remarkably well. It is self-limiting in
r esp ect to the different tape sp eeds in
r egular use, G7 having no noticeable effect at 3%, ips, boost at this speed being
ensured mainly by Ga) while at 7% ips,
G8 and G7 between them, together with
the tape and head losses, give an ideal
rise up to about 12,000 cps, after which
the response drops steeply. At 15 ips,
the useful r esponse is held up t o around
15,000 cps. All these figures, of course,
are to some degr~e dependent on the
geometry and adj ustment of the heads,
as well as the characteristics of the tape
itself. Recording bass boost, to accord
with NARTB requirements, is cover ed
by the feedback network GM ) R 7A.) R 10 )
R 10A ) and if additional treble boost is
desired for pulse and similar work, R 10
may be bypassed by a capacitor of 25
fJ../J-f to 200 fJ../J-f, the actual value needed
being determined by experiment in association with the necessary test gear .
(It should perhaps be remarked that, if
this modification be made, it is unpleasantly easy, without great car e in lead
dress, to convert the amplifier into an
effective pulse generator on its own). As
G7 and Ga offer a comparatively lowimpedance path at the bias frequency of
50 kc, a trap consisting of a 20-mh coil
tuned by a 400-/J-/J-f capacitor ter minates
the recording amplifier.
Record level monitoring is by the sustained peak-indicating VTVM. V S ) R 1 S )
R 14 ) R 15 ) R 16 ) R 17 ) G11 ) G l 2> and delay on
the needle return is determined by the
RC network G12> R 16 time-constant,
which may be multiplied, by var ying
G12) without upsetting the operating
conditions other than incr easing the
hang of the needle on peaks. p . taps off
the monitoring signal to a figure convenient for the meter to handle, while
G11 bypasses str ay bias which might prevent the meter from zeroing accurately.
It is possible that R 1 5 will be a subject
for adjustment, as the necessary backing-off voltage on the cathode of V 38 is
affected by individual valves as well as
by the delay network; but 470k serves in
the majority of cases. (U.S. constructors
Fig . 3 . Cathode-follower output stage in
replay amplifier.
anode load. This in intentional, again
with grid current in mind, to avoid the
possibility of noise when operating thc
gain control. G9 passes the amplified
signal from V 2A to the grid of V'B)
which is, as can be seen, employed rather
as a low-output power amplifier than as
a voltage-amplifier; and G10 couples
V 2B to the r ecording head by way of
R 11 and R 1 2 ) willch have the effect of
making the tube appear as a constantcurrent generator to the head, an essential condition in view of the inductive
component of the windings. G7 and Ga
18
+
Bpr
150V
Fig. 4 . Another output circuit which g ives
good ou t pu t in to 600-ohm load circuit
with low distortion .
AUDIO
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O UTPUT
'---+---I~6OOw
•
JUNE, 1959
Fig . 5. Schematic of auxi liary small power amplifier.
may prefer a cathode follower driving
a standard VU meter.)
T , } Cw V . comprise the bias- and
erase-oscillator section. (T 1 is the Ferrograph 579 coil, and V 4 the EL84 steepslope power p entode.) P 3 permits of adjustment of grid drive for maximum
output consistent with good waveform,
which should be a pure sinusoid, free
from second harmonics; and current
feedback via R IB helps ensure this. C' S}
by acting as a reservoir of B+, prevents
the too rapid cessation of oscillation
when the B+ supply is switched off via
the deck function switch, this being essential to ensure that the heads will not
be left in a state of permanent magnetization, with consequent noise on the
tap e. Because of the comparatively low
impedance of the heads, T 1 is wound
wijJJ. a step-down secondary winding, and
the erase head takes its current from this
by way of C 16J the record head being fed
through C 17 and P s} the potentiometer
providing an adjustment for optimum
bias, the value of which is stated by the
maker s of the deck for each individual
head. (Note th at r ecording bias is not
taken across the whole head winding, but
is brought in via a tap about a third of
the way from ground terminal.)
On replay, the head is coupled to V 5
via the deck switch and T 2 } the F errograph step-up transformer type 977,
which has a ratio of 1:6; and the coupling between V 5 and V 6 includes the
r eplay equalizing network, where most
of the bass boost is provided, as well
as a small increment of treble lift to
help compensate for high-frequency
losses during REPLAY. C20 presents an
increasing r eactance as the frequency
decreasEs, in accordance with the formula X=10 6 /2 rc fC, (where f is in cps
and C is in /kf), its shunting effect on the
signal becoming less and less, RZ4 providing the step, while the RC network
R Z3 } C 19 .1 boosts treble according to the
same formula, the decreasing reactance
of C 19 11 bypassing R Z4 at the upper end
of the scale. V 6 is another EF86, triodeconnected, and P 4 is the output potentiometer. For long lines, this may be rep laced by a control of down to lOOk,
with slight reduction of maximum output signal, or it is possible to substitute
OCTAL
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P5
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Fig. 6. Exploded underside of bare chassis.
AUDIO
•
a double triode for the EFS6, the second
half being arranged as a cathode follower. The circuit is given in F ig. 3, and
may be used for feeding into lines up
to 20 ft. long, provided the terminations
are not less than about SOk ohms. With
600-ohm terminations, severe distortion
will occur with this type of cathode
follower , even at low levels, and it will
be more satisfactory to retain the EF86
and follow it with an ECC82 connected
as a cathode-follower in the circuit of
Fig. 4, which will permit of a maximum
output signal of about 2 volts into such
a terminating impedance, with no measurable loss over the whole of the audio
r ange and beyond. (From the circuit as
given in F ig. 1, up to 3 volts ar e available from a tape fully modulated on the
recording section of the amplifier.
It will be noted that B+ for the r eplay
section is drawn from the junction of
Rs and C 3 : and this is absolutely essential if the power supplies as a whole
come from the main power amplifier
into which the output from V6 is fed.
The r esponse on the replay side is such
as to permit of appreciable signal being
passed at 2 cps or even lower, and in
most cases, if B+ is taken f r om the
junction of C 23 and R zrl1 , and providing
of course that the low-frequency response characteristics of the power amplifier are good enough, interaction will
cause motorboating at any freq uency
between 0.5 and 10 cps, depel, ding on
the circuit constants.
Figure 5 is the schematic of an auxiliary small power amplifier, for monitoring with three-head decks. Not to put
too fine a point on the matter, it can
fairly be described as the triumph of
brute force and ignorance over civilized
design. It really is a disgraceful example
of low cunning. A very flexible tonecontrol system is simulated by the simple
expedient of cutting bass and boosting
treble as a permanent feature, and then
reversing the process as required, by
means of P 2 and P s . Negative feedback
to minimize hum and distortion is provided by R6 and R 9 ) and, as the output
transformer is outside the feedback
loops, there is very little risk of instability ; so this component does not have to
be in the luxury class: the cheapest will
do. The experimenter will no doubt try
various values for R 6 } and the lower it is,
the greater th~ feedback. The only restriction in this direction is when the
shunting effect of R6 on R s is so great as
to reduce the load on V , B to too Iowa
figure. Substitution of the ECC83 by an
ECC81 will put off the evil, although the
gain of the amplifier as a whole will be
reduced, even without feedback. Lead
dress is unimportant, as it appears to be
quite impossible to make mistakes in that
direction, but if the WB / U is used also
as a power source for the TW IPA2, B+
is better drawn from the cathode of the
19
JUNE, 1959
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Fig . 7. Cha ssis with sockets and heater
w iring in place .
GZ30, and not from the junction of R , .\
and 0 ,0 , The amplifier is unworthy of
further comment. Suggestions as to obtaining the parts for it will be given
later, and the total cost need be no more
than twenty dollars, and may well be
much less, as most of the bits and pieces
will already be in most constructors'
junk boxes.
Returning to the TW IPA2, the general dress should follow, in broad outline, that of the commercial article
the recording section. The corresponding
socket holes are noted, and that going to
the Gr pin is joined via a short length of
# 20 or heavier wire to any near point
on the chassis, for which one of the
socket fixing rivets is an obvious choice.
The reason for this connection is to keep
the deck frame and motor grounds away
from the main amplifier ground point.
Five tags on the octal socket are thus
available as anchor points, and the fourwire power cable is now wired into place.
It carries heater supply, and B+ from
the power-pack, but if these supplies
are taken from the main replay power
amplifier, the ground return from this
is not used, or hum will certainly result.
The replay output co-ax shell is the only
ground connection between the two amplifiers. R27A. is wired across the B+ "in"
terminal and the remaining spare on the
socket, which is now thc main B+ bus.
Next, all the controls and the two jacks
are fitted into their respective positions,
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ITALIC NUMBERS REFER TO CONNECTION POI NTS O N FIG.· I .
Fig. 8 . Arrangemen t of parts o n resistor stri p (group board ),
which, one may be sure, is arranged with
ease of construction and duplication of
results in mind. The suggested chassis is
of mold steel, and is fitted with a bottom
cover, so totally enclosing the works, and
excluding external hum and noise pickup. An exploded view of the inside is
shown in Fig. 6, and the tube-socket and
control holes can be drilled or punched
either before or after folding, with equal
facility. Apart from the main openings,
the amateur will probably find it easier
to drill as he goes along, rather than
·measure and mark out first.
The factory wiring procedure is based
on the assumption that the deck cable
forms are attached, and the power cable
is wired in, before any other work is
done. (It is only an assumption, but it
helps clarify the position in the operator's mind.) With this end in view, a
three-way cable-form is connected to the
lettered terminal-strip · 'under the deck,
one lead being joined to Gr, a ground
point on the frame, another to A, which
carries the recording signal, via the
switching, to its appropriate head, and
the third to G, the B+ bus for the oscillator. The remote ends of the form are
soldered into three of the pins of an octal
plug, for which a socket is provided on
the real' of the amplifier chassis, behind
and then the tube heaters are wired up;
but note that the form between V 2 and
V 6 carries, in addition to the heater
wires, one extra wire each for (1) the
B+ line from the j unction of Rs and a s
to the replay section, (2) the cathode
lead from V 6 to R26J af l J which are located on the main group-board, and (3)
the connection between the spigot 2 of V 6
tube socket to the spigot of V 2 socket.
The next operation is the fitting of the
two co-ax inputs, one for the replay input and the other for output, and the
shell are joined, via solder-tags under
the fixing r ivets, by a short piece of
# 16 wire. Figure 7 shows the heater
wiring, together with two of the extra
wires, as well as the B+ wire from the
octal socket, ready for soldering to the
main group board.
The oscillator section is now wired, as
is the V 9 circuitry, a length of insulated
wire being first soldered to pin 3 of V 3
socket for later connection to the junction of Rl5J Rm which are on the main
group-board. Connections for the B+
line for Vs and V. are by way of a 4-pin
socket on the chassis and corresponding
plug and cable-form to the deck, and
this socket also carries the bias, erase
and ground returns i.e. 2, 3, 4, and 1 in
Fig. 2. The main group-board, which
has already been assembled and wired, is
then bolted into place, and the replay
section B+ f eed wire-which, as will be
remembered, is included in the form
from V 6 to V 2-is connected to the junction point of R 2 and R 3 J another wire
from the B+ terminal on the four-pin
socket being joined to tbe top of R 15'
0 23 and 0 3 are now soldered into place,
and the remaining lead in the form, from
V6 cathode, is wired to its appropriate
position on the group-boai'd, the latter
being shown in Fig. 8. The shield around
the replay section is prepared by mounting a small terminal strip on it, and
soldering on to this all the remaining
components belonging to Vs and V6J
with the exception of R 22 J Ow R ~ .J R 25 J
and a2 0J which are laid as near to tkeir
(Oontimted on page 74)
2 Mr. Wayne tells us that the "spigot" is
the center shield of the noval socket.
Fig. 9. Und e rsid e v few of comple ted amp lifier.
20
AUDIO
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•
JU NE, 1959
The Trimensional Stereo
Speaker System
I
VICTOR BROCINER';'
The desirability of a compact, single-cabinet speaker system for stereo
has led to the development of a new design incorporating the equivalent of two 3-way speaker systems in one cabinet of moderate size.
involving two
separate speakers, no matter how
compact, are not always feasible in
modern living rooms. Locating' the
speakers for best stereo performance
sometimes leaves no way of positioning
furniture in an attractive manner. 'fhe
requirement that the listener be on or
near the center line between the two
speakers makes locating two sep arate
systems and seating arrangements even
more of a problem.
For many homes, the ideal solution
for stereo would utilize some means
whereby the two normally separated
speaker systems are combined in a cabinet of modest proportions, while providing adequate separation and spread
of sound for real stereo. This was the
basic objective in developing the University "Trimensional" speaker system.
A maximum cabinet width of 30 in. was
specified.
Since it is required that the speaker
systems for the two channels be physically close together and that the apparent sound sources be separated by a
considerable distance, the obvious solution is to direct the sound from the
speakers in such a manner that the listener hears mainly the sound reflected
from the walls of the room. This idea is
illustrated in Fig. 1. The usual wall surfaces reflect sound fairly well in the
frequency range above 150 cps or so,
and it is within this r ange that the
stereo effect takes place. The difficulty
in the simple arrangement of Fig. 1
is that, since the speakers themselves
TEREO INSTALLATIONS
S
* Staff Consultant, Unive1'sity Loud·
speaJce1's, I nc., 80 S. Kensico Ave., White
Plains, N. y,
I
¢
,I
Fig. 2. Sound paths from one side of
speaker; similar paths exist on other
side.
are not extremely directional, a good
deal of sound reaches the listener directly from the speaker s, and the
sources appear to be close to the cabinet.
The remedy, of course, is to make the
speakers directional, but, for frequencies
down to 150 cps, the space r equired to
accomplish this is not compatible with
the requirement that the width of cabinet be kept below three feet.
The solution adopted was to place
two doors on the front of the cabinet
where they are out of the way wben the
unit is not in use, and arranged so that
they can swing outward to the positions
shown in Fig. 2, when using the speaker
for stereo. The doors are large enough
to reduce the direct sound from the
speakers to a sufficient extent to keep it
from masking the sound reflected fro111
the walls. A certain amount of sound,
of course, "leaks" around, or is diffracted from the edges of, the doors, but
the effective separation between these
apparent sources is of the order of 4 to
5 feet. The over-all effect is similar to
that of a phantom channel in the center
to provide a continuous sound field.
Figu1'e 2 also shows the way in which
sound is reflected from the rear of the
deflector doors, from the r ear wall, and
from the side walls to for m two broad
sound fields which ar e continuous
through the center. The paths followed
by the sound are as follows;
The resulting virtual sources of the
sound, or rather the a1'eas from which
the sound seems to come, spr ead not
only beyond the confines of the cabinet
but beyond the walls of the room. The
resulting spread is actually gr eater than
that obtained with a conventional twospeaker arrangement. In effect, a CUI'tain of sound is produced that extends
across the end wall and beyond both
side walls.
An interesting consequence of the reflections from the walls is illustrated in
Fig. 3. Unlike the situation obtained
with two speakers, in which there are
two sound sources, there ar e multiple
virtual sources, located behind the wall,
spread out in depth. The sound field
created by these virtual sources, plus the
diffused sound arriving from the rear
wall, is seen to be three-dimensional. It
is this quality that inspired the name
"Trimensional." The sense of depth produced is definitely audible, and has been
judged by a large proportion of the listeners in exhaustive listening tests, to
add appreciably to the r ealism of reproduction.
Sometimes an engineering development yields unexpected dividends. The
nature of the broad sources created by
the Trimensional speaker is such that
a good stereo effect is produced throughout the room. See Fig. 4. In the listening tests previously referred to, all of
the audience heard stereo, regardless of
their positions. Demonstrations under
difficult conditions have confirmed this
fact- even at the 1959 San Francisco
International High Fidelity Show at the
(1) Sound from the speaker reflected
by the side wall.
(2) Sound reflected fro m the rear wall
and then again by the side wall.
(3) Sonnd reflected by the front deFig. 1. Two speakers, with sound reflected from side walls.
AUDIO
•
flector, then by the rear wall, and
finally by the side wall.
(4) Sound directly from the speakers,
spreading around the deflectors.
Fig . 3. Virtual sound sources from direction of reflections .
21
JUNE, 1959
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AmericanRadioHistory.Com
I
CHANNEL
I
A
CHANNEL
B
Fig . 4. Over-all sound dist ribu ti o n.
Cow Palace, where no side-walls were
provided in the "booths," and it was
possible to install p lywood p anels no
more than 4 ft. wide to simulate the
end walls of a room.
Construction Details
The construction of the speaker system is shown in Fig. 5. Front and interior views are in cluded in Figs. 6 and
7. It will be seen that there is an S-inch
speaker for the mid-range, plus a compression-type horn-loaded tweeter, facing in each direction. The upper
crossover fl'equency is 3000 cps; the midrange units covel' the range down to 150
cps. The tweeter and mid-range speaker
on each side are mounted in a closed
compartment, independent of the lowfrequency speaker, to prevent the latter
f rom driving the mid-range direct-radiator speaker s. These compartments are
of adequate size to ensure that the resonant frequency of the mid-range speaker
r emains below the crossover frequency.
The 150-cps crossover frequency was
chosen on the basis of extensive tests,
which indicated that the stereo effect
occurs over a f r equency range that extends down to this region. Thus, all
the frequencies involved in creating the
directional effect are covered by the
speakers mounted in the sides of the
cabinet.
There being no directional effect below
150 cps, the low-frequency sour ce can
be located according to considerations
of best performance, greatest convenience, appearance, and ease of assembly.
For the same reason, it is not necessary
to use t.wo separate woofers. In the Trimensional sp eaker , the bass of both
channels is reproduced by one speaker.
If all stereo recordings were made
with moderate microphone spacing, such
IORANGE
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Fig. 5 . Diagram of speaker arrangement.
that both microphones received essentially identical signals below 150 cps,
it would only be necessary to reproduce
the bass range from one channel, boosted
3 db to make up for the absence of the
other channel. However, with the microphone techniques currently in use, it
can easily happen that one channel contains practically all the bass, such as
when a group is being recorded with one
microphone close to the bass instruments. There is, of course, no way of
predicting which channel will have most
of the bass. The logical answer is to
combine both channels up to 150 cps.
This is accomplished at no sacrifice in
performance, affording an appreciable
saving in space and cost.
The combination of the two channels
below 150 cps can be effected by means
of a special filter and transformer network. A typical schematic of such a
filter is shown in Fig. S. It is seen to
be rather complicated, and it is expensive, too, since the isolation trans-
coupling that may occur between the
windings has no effect on the latter.
The single woofer used in the Trimensional speaker system is a highcompliance design, capable of large excursions without departing from linearity. The moving system has high
mass, as required for good r esponse,
down to, and below, 30 cycles. The freeail' resonance of this 12-inch unit is IS
cps.
Bass Enclosure
In order to obtain optimum response
to 30 cps with minimum excursion of
the voice-coil, the 2 cubic-foot bass enclosure is "vented" by means of a tubular duct. 1 Through careful adj ustment
of system Q's, excellent damping is obtained, as indicated by the tone-burst
photograph in Fig. 10.
Note the almost nonexistent "hangover" which is actually less than the
amount to be expected from the listen-
Fig . 6 . Exte rnal
view of the
speaker
with
doors open. When
closed, the doors
cover the entire
front .
former must perform well down to the
lowest frequencies to be reproduced and
must be capable of handling the full
power of one channel.
A simpler and more satisfactory solution of this problem is afforded by the
use of a woofer with a dual voice coil.
Figul'e 9 shows the schematic of the
speaker circuit and indicates the essential simplicity of the system. The woofer
has two voice-coil windings, bifilar
wound, with four leads brought out to
terminals. Each winding is connected
to its amplifier channel through a choke
which acts as a low-pass filter. The two
voice-coil windings simply add the bass
from the two channels.
There is practically no transformer
action between the two voice coils at
low frequencies; the two amplifiers are
electrically isolated, and no undesirable
interaction can occur between them. The
elimination of a common ground connection is also an advantage. At the
higher frequencies, the chokes isolate the
voice coils from the amplifiers, and any
22
ing room itself. The woofer-enclosUl"e
combination is designed for operation
from any high fidelity p ower amplifier
having high damping factor.
The duct provides a load on the
1 Victor Brociner, "Compact ultra-linear
speakers for stereo." AUDIO, Aug. 1958.
Fig .
7.
Internal construction
speaker.
AUDIO
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•
of
the
JUNE, 1959
PHAS E
SWITCH
8w
8w
CHANNEL 1
AMPLI FIER
CHANN EL 2
AM PLI FIER
COM
COM
TRANS FORME R
Fig . 8 . Ste re o ne tw ork to feed signols fro m tw o a mplifi ers to a singl e
w oofe r.
MID- AND
MID- AN D
H. F. SPKR S
H.F . SPKRS
COMMON
WOOFER
speaker , in the vicinity of cabinet r esonance, that is practically pure radiation
r esistance. At the bottom of the r ange,
most of the power is radiated from the
duct; as a result, voice-coil excursion is
markedly reduced, with corresp onding
reduction in distortion. This action is
evidenced by the presence of a noticea ble breeze in the vicinity of the vent
when low frequencies ar e r eproduced at
high level. If the vent is closed while
30 cps is fe d to the sp eaker at high
power , the incr ease in motion of the
cone is readily seen.
In cidentally, there seems to be some
popul ar misconcep tion about the r easons for using a duct instead of a simple
op ening or p ort in " phase inverter " enclosures. Sp ecial p rop erties are somehow associated with a duct that mak e
for impr oved p er formance. The usual
explanati on is that the duct calls for an
opening of consider ably greater ar ea
than a port, that this provides with a
larger value of radiation r esist ance and
that this, in turn, r esults in more bass
a nd better damping .
From an intuitive standpoint, this
looks ver y p lausible. Does it bear ana lysis ~ Th e r adiation r esistance, in me-
chanical units, of a large opening is
gr eater th an that of a small one, just
as it is for a large sp eaker comp ar ed
to a small one. I n the case of a sp eaker
cone, which is driven by a fO?'ce determined by its electromechanical coupling
and the app lied power , more power is
radiated the larger the cone. But a port
is driven by the p?'essw'e develop ed in
the box. If we use a large opening, the
fluid velocity out of the p ort will be
low er. The lower velocity counteracts
the effect of the increase in radiation :r;esistance ; in f act, it compensates it exactly. Th e pMV e?' out of the port is not
affected by its size.
The signi fica nt difference between a
duct and a p ort is that the f rictional
loss in a port incr eases mor e r apidly
than th e in er tance as the port size is
decr eased. As the p ort becomes very
small (a f raction of a squar e inch), the
resistan ce becomes so large that the system becomes over -dam p ed and the portcabinet combination no longer f unctions
as a phase inverter. Tuning a small box
to a low fr equency r equires a small
port ; a duct allows a larger op ening t o
be used, which avoids excessive r esistance in this "circuit element." The lower
DUAL-VOICE-CO IL WO OFER
'"c::::J7
I
I
4
FROM AM PLIFIERS
CHAN NEL 1
CHANN EL 2
Fig. 9. Schematic of Tri me nsional circui try.
AUDIO
•
Fig . 10. 50-cps ton e bu rst. Irre gular ity
of modulation e nv e lop e is inhere nt in
the te st e quipm e nt.
air velocity also prevents the pr oduction
of n oise due to tur bulence.
Efficiency and Frequency Response
The efficiency of the system is moderately low ; this is typical of small cabinets having extended bass range. E xperience has shown, however, that a dual
12-watt ster eo amplifier provides very
satisfactory oper ation for average home
use.
It will be remember ed that most of
the energy above 150 cps reaches the
listener after one or mor e reflections . .
At each r eflection ther e is a certain
amount of loss. The nature of most surf aces is such that this loss is gr eater
the higher th e frequency. So, if the
f r equency resp onse of the sp eaker were
flat, the listener would heal' a r esp onse
I
[g) . 1
I
Fig . 11 . Arrangement of speaker in different locations .
that is deficient in highs-progr essively
so as we go up the frequency scale.
In order to compensate for this, the
Trimensional sp eaker is designed to
have a r esponse curve that rises with
f requency. This r esponse can be varied
at will to compensate for the differ ent
reflective characteristics of various wall
materials, construction, and de(!orative
treatment. L-pads controlling the midrange units and tweeter s on each side
permit adjustment of the r esponse char acteristic. If the listening room is not
symmetrical acoustically, it is p ossible to
achieve balance both tonally, and in
loudness, by means of these controls.
The r ange is sufficient to enable the
user to compensate for sizable losses
such as may be caused by nearby upholster ed furniture or draper y. An obstruction adj acent to the sp eaker can
be taken care of by turning the door on
that side slightly f Ol'ward to p revent
blocking of the lower f requencies. At
the same time, the controls described
(Continuecl on page 74 )
23
JUNE, 1959
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Two More Ears
M. DAVID WEISBERG ':'
One effective method of making a high-quality stereo headset from a
surplus item with a minimum of effort and expen.diture .. Many are the
uses for such a device, both in the laboratory and In the listening room.
conception of a
pair of headphones is that of a device
that holds the studio engineers' head
together. Or perhaps the earmuffs that
the "ham" down the street wears so as
not to hear the wails of irate TV viewers.
This attitude may be due to t he fact that
headphones are not g'enerally associated
with living r oom listening. My own ex. perience with them had been confined to
the "ham" shack or the test bench. Some
time ago, the need arose for some way
of listening to the audio system without
annoying others. It was tried, with a
pair of 'phones at band, but the results
seemed to justify all the derogatory remarks heard on the subject.
The answer to complaints of poor reproduction through 'phones may be had
by understanding them. There are three
basic types : magnetic, crystal, and dynamic. The fir st constitu tes about 90 per
cent of the commercial and surplus market and is the type found in telephone
handsets. The least expensive of the
three, it consists of an iron diaphragm
close to one or two electromagnets with
permanent magnet cores. These are
rugged units of 2000 to 8000 ohms impedance, the best of which are lacking
T
HE AVERAGE CITIZEN'S
in response at both ends of the audio
range. Peaked in the 300- to 3500-cps
range, they are designed primarily for
speech and will seriously distort when
subject to dynamic, wide-range audio
material.
The crystal 'phone is similar to the
crystal microphone in that they both
employ piezo-electric salts. When subject to an alternating current, the crystal moves and in turn moves a fiber diaphragm linked to it. This produces
sound. These are high-impedance devices
of medium price, and while lacking in
low-frequency response, they are capable
of satisfying the casual li stener. They
are delicate, however, and may be rendered useless by running d.c. on them,
or by exposure to shock, heat, or moisture.
The remaining class, the dynamic, is
the least common and the most expensive. It is basically a miniatUTe PM
speaker, consisting of a moving coil
connected to a cone, usually of fiber.
Possessing the widest response of all ,
the dynamic 'phone is a low-impedance
device. It is usually available in some
standard line value, such as 600 ohms.
It appears then, that the dynamic
type is the choice. A look at a current
catalog, however, may prompt the reader
to leave the order blank blank. The tag,
over for ty dollars, will deter all but the
most heavily endowed. If the surplus ads
are consulted, you will find "moving coil"
units available for seven or eight dollars.
These are dynamic units used by the
military for audiometer tests and are
duplicates of some units available on the
commercial market. This is the type to
purchase.
Conversion Procedure
The degr ee of conversion is up to the
user and his requirements. If the application is monophonic and impedance mismatch can be tolerated, the 'phones may
be used "as is." For greater flexibility, it
is advisable to change the cor d. Not only
will the cord be too short but it is unsightly and, finally, is not wire but
tinsel covered threads to which it is impossible to solder. On the r eal' of each
unit there are two screws. Loosen each
a tUTn or two and the wires will come
out. Remove aU the cord from the headband. Using foUl' conductor intercom
cable, strip back the jacket for 18 in.
Wrap Scotch brand electrical tape
around this point to build up the cable
* 2707 Creston Ave., Bronx 68, N . Y.
diameter. Examination of the headband
will reveal fOlll' cable clamps, two on
each side. One is larger than the others
and this is one that holds the cable. Slide
plastic spaghetti over two of the wires,
route them over the headband and under
the clamp. The remaining two wires are
treated in the same manner, being run
. under the clamp adjacent to the cable.
Examination of Fig. 1 will make this
clear. The headband shown in the photo
was taken from a pair of magnetic surplus 'phones, the wires being run through
the leather loop. You now have the two
pairs of wires terminating near thei r respective earpieces. Bare the ends and
solder each into a piece of brass tubing
1/8" by %" long 01' into the screwdriver
slot of a machine screw of the same
dimensions. Slide these into the 'phone
terminal holes and tighten the screws.
Tbe other end of the cable may be
terminated in one 01' two plugs, depending on intended use. For monophonic
use, connect the two units in series or
Fig . 1. Modified phones showing wiring method, 4-pin plug, and ma tching connector .
parallel, using a standard phone plug.
24
AUDIO
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•
JUNE, 1959
N€LU 1And designed for a long future!
FISHER DOES IT AGAIN! Year after year, tuner after tuner, there is only one best-THE FISHER. Today,
the leader is the FM-l 00, latest in a series of FISHER FM tuners now used by radio stations, the Satellite
Tracking Project of Ohio State University and by many government agencies. The reason is simplethese tuners meet the exacting standards of performance and reliability required by professional users.
- And where standards are concerned, the audio enthusiast is, in his own right, a professional. He desires
maximum sensitivity for optimum reception of stations near and far. FM-l00 SENSITIVITY is 0.8 microvolts
for 20 db of quieting! - The audio enthusiast wants an FM tuner that permits simple adaptation to
stereo. THE FM-l 00 IS CUSTOM-DESIGNED FOR STEREO. It has space directly on its own chassis for installation of a mUltiplex adaptor. Moreover, it includes feed-through facilities for FM-FM and FM-AM stereo
as well. - The audio enthusiast expects maximum fidelity. THE FM-l00 OFFERS FOUR WIDE-BAND IF STAGES,
uniform frequency response (20 to 20,000 cps) and less than 0.5% harmonic distortion. - The audio
enthusiast wants an FM tuner that eliminates noise when tuning between stations. THE FM-l00 EXCLUSIVE
INTERSTATION NOISE SILENCER automatically eliminates noise, side-band response and unwanted weak
and noisy signals. For the audio enthusiast who buys the best at the outset, there is only one truly logical
choice-IT IS THE FISHER FM-IOO TUNER.
$159.50 Cabinet, $24.95
Slightly Higber i1l the Far lVe,t.
WRITE TODAY FOR COMPLETE DESCRIPTIVE LITERATURE
. . .'. .
.
•
Export: Morhan Exporting Corp., 458 8roadway, New York 13, N. Y.
AUDIO
•
JUNE, 1959
25
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For binaural use, connect each unit to
its own phone plug. Proper phasing may
be had by noting the color code of the
wires, and to which terminal on the headphone each one goes. When connecting
the wires at the p lug, join like terminals
under one screw and the remaining two
under the other. Don't make the mistake
of wiring the two leads of one phone
together or to both plugs (in the stereo
connection). Before attaching the plug,
make sure all the hardware is on the
cable and facing in the right direction.
The connector shown in Fig. 1 is a fourpin type which allows attachment of
extensions wired for varied purposes.
The phones are ready to use at this
point, but, unless your pr~gram source
terminates in 250 or 600 ohms, there will
be a power-transfer loss and the frequency response will suffer. However,
you may not be able to notice either,
since the phones demand far less power
than is normally available.
The truly dedicated audiofan may demand a closer match and this may be
had in two ways. The nominal terminal
impedance of each phone is 300 ohms.
Series connected, this represents 600
ohms at the plug, or 150 ohms in the
parallel connection. A small transformer
to match 150 or 600 to 4, 8, or 16 ohms
will provide a proper match. This not
only entails spending money, but it
seems just a bit odd to bave to use three
transformers between the output tubes
and the voice coil. There are three, for
within each unit there is a miniature
300-to-8-ohm transformer. By removal of
these, you have your pick of 4 or 16 ohms
monophonically, or 8 ohms for each
channel of a stereo system.
Removing Transfo rmers
To remove the internal transformers,
remove the phones from the headband
and note that these do not unscrew as do
the magnetic type. That would make
your job and this article shorter. Place
the unit face down on a hard surface
and pry up the crimped edge of the
retaining ring, using a knife or screwdriver. The latter is preferable, since it
won't go too far into the table when it
slips! After the crimp is undone, slip off
the retainer ring and the black bakelite
cap. This will expose a silver metal disc
with six brass rivets anchoring it to the
case. With a small bit, drill out the
rivets, going only deep enough to remove
them. These will be used in reassembly.
The fiber washer on the rear of the case
will be loose now and it may be removed.
Slide a knife blade between the case and
the metal disc and work it around. The
assembly is now free of the case except
for the wires soldered to the cord terminals. Unsolder these at the terminals.
Remove the metal dise and, you can see
the treated fiber cone. Some units may
have a thin latex covering over the rear
with the second headphone unit, making
sure that the wires from the voice coil
go to the same respective terminals as in
the fi,rst unit.
RETAINING RING
Applications
BA KE LITE DI SC
RIVETS
SILVER METAL
f
t
,
~
f
f
DISC ~~~
SPEAKER ASSEMBLY -
CASE
FIBER WASHER
Fig . 2 . Assembly detail of a single head phone uni t.
of the speaker assembly. This is presumably for waterproofing and may be
removed and discarded. On one side of
the speaker, the transformer is held in
place by a drop of solder and two integral spring clips. Cut the two voice-coil
wires as close to the transformer as
possible. Unsolder, push in on the two
clips and remove the transformer. Scrape
the clipped ends of the wire and resolder to the cord terminals on the case.
Use spaghetti to avoid shorts to each
other or to the case. Check the connections with an ohmmeter. The voice coil
reading should be 10 to 12 ohms. Check
each wire for a short to case. Refer to
Fig. 2 during reassembly, in the event
you forgot what-goes-where. Use Neoprene or Plio bond cement between
washer and case, case and speaker, and
the speaker and disc. This is a rubbery
adhesive that will help hold everything
together and prevent any metal-to-metal
chattering. Reassemble, line up all the
rivet holes, and replace the rivets. Face
down, on a hard surface, deform the
ends of the rivets with a center punch
or small screwdriver. Place the black
bakelite cap over the metal disc, noting
the two projections that mate with holes
in the disc. This prevents rotation of the
cap. Place the fiber washer over the rear
of the case, the retaining ring over the
front and reel'imp the assembly together.
The ring will appear a bit chewed up but
this won't show when ear cushions are
added. Now proceed in the same manner
26
The use of the phones will be determined by the needs of the reader, but it
!Should be pointed out here that phones
have not been designed to compete with
loudspeakers. It has been the purpose of
this article to provide, at a cost commensurate with utility, a means to enjoy
audio material where the size or volume
of a loudspeaker precludes its use. The
fine timbre of a properly baffled woofer
'will just not be present in a pair of
headphones. The physical configuration
limits the listening to one person. With
these limitations in mind, it might seem
that there is little use for a headset. This
is not quite so, for there are many instances where phones may even be necessary. When recording, for example, it is
wise to use phones for mon itoring to
avoid feedback to the mike. It is manna
to the modern cliff-dweller, who, Fletcher
Munson or not, has to keep the power
down when listening at midnite. By the
same token, it eliminates outside noises
while you're trying to hear soft passages.
Low-power. amplifiers will overload the
headset long before they reach saturation.
So little power is required that it is
advisable to use a "T" pad in the headphone line to reduce the volume. When
stereo in considered, think of the ease of
channel balancing without having to
wear a path thru the rug between your
easy chair and the preamps. Furthermore, the listener's position in the room
i5 no longer critical.
After many hours of listening by headset to varied selections, both monophonic
and stereophonic, several comments are
in order. It was found desirable to boost
the bass and droop the treble slightly.
The bass lacks the dram a of a large
enclosure, but it has no "boom" and is
adequate. If the headphones are pressed
tightly to the ears, the bass will be more
pronounced. Because of this, ear cushions should be selected for tightness of
fit. At first the headset may feel Ullcomfortable, but after a shod time they
are unnoticed. Because of the great sensitivity, extremely soft passage will be
heard quite clearly. In fact, in the absence of a signal, tube noise and so on
may be heard. This is rna 'ked by the
signal, the signal-to-noise ratio being the
same as when speakers are us[ d. Due to
the droop at the low end of the audio
range, hum and rumble al'e no more
objectionable than with speakers. When
listening to stereo, the sound seems to
come from within the listener's head.
The spatial effect is quite pronounced
and this listener has often lapsed into
an unawareness of the fact he was hearing stereo through headphones.
IE
AUDIO
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•
JUNE, 1959
~Nevv
Stereo Tape Recorder
Cyb~~netically engineered
for intuitive operation
Fluid smooth, whisper quiet... with featherli ght t ou ch y ou control t ape m ovem e nt
with the central joystick of your Newcomb
SM-310 . Thi s excitin g n ew ste r eo ph oni c
r eco rd-pl ayb ack tape m achin e has b een
cy b ern e ti cally e n' gin eer eq. to fit you .
Intuitively, you sens e how to opera te this
handsome instrument. The natural movement, you find , is th e correct m ovem ent.
Loading is utterly simple. It is alm os t impossible to make a mistake. The transport handles tape with remarkable gentleness, avoids
stretch and spilling.
Th e N e wcomb SM-310 rec ords ste reophonically live from microphones or from
broadcast or recorded material. There are
mlxm g controls on both channels for combining "mike" and "line:' The SM-310 records and plays back half-track monaural
also. So versatile is the machine that you
may record and playback on either or both
channels in the same direction.
The SM-310 is a truly portable unit which
combines the fea tures required by the professional and desired by the amateur for onlocation making of master stereo tapes. F or
example, the SM-310 takes reels up to lOW',
has two lighted recording level meters arranged pointer-to-pointer for ready comparison, has a 4 digit counter to pinpoint position
without repeatin g on any size reel. F or playback there are a "balance" control and a
ganged volume control. Head cover removes,
giving direct access to tape for easy editing.
The Newcomb SM-310 is a sleek, rugged,
compact machine, discreetly styled by an
eminent industrial designer in easy-to-live·
with shades of warm gray and satin aluminum ... a gratifying, precision instrument for
th e creative individual who is deep in the
art of tape recording. Eight, tightly-spaced
pages are required in a new brochure to
describe the SM-310 in detail; send for your
free copy.
Advance showings in New York and Los
Angeles proves an unprecedented demand
for this instrument. We urge those who desire early delivery to place their orders now.
DEPT. T-6
NEWCOMB AUDIO PRODUCTS CO., 6824 LEXINGTON AVENUE, HOLLYWOOD 38, CALIFORNIA
NEWCOMB SALES REPRESENTATIVES
CALIFORNIA, San Francisco 3, William .J. Purdy Co., 312 Seventh St.; COLORADO, Den,er, Cox Sales ~o ., P. O. Box 4201 , ·50: Denver Station ; FLO RID A :
Tampa 9, Morris F. Taylor Co., 4304 Corona St.; Winter Haven, M. F. Taylor Co., 940 Lake Elbe rt DrI~e ; GEORGIA, East Poont, M. F. Taylor Co. , Box 308 ,
INDIANA, Indianapolis 20, Thomas & Sukup, Inc., 5226 No. Keystone Avenue; MASSACHUSETTS, Brookline 46, Kenneth L. .Brown, 54 Atherton Road; MARYLAND, Silver Spring, M. F. Taylor Co., P. O . Box 111; MICHIGAN, Ferndale 20, Shaico, 23525 Woodward '!ve.; Grand RapIds 6, Shaico, 700 Rosewood Ave. ,
S. E.; MISSOURI, Clayton 5, Lee W. Maynard Ca., 139 N. Central ; NEW YORK, East Meadow, Harry N .. RelIes, 1473 SylVIa Lane; Syracuse 14, Paston·Hunter
Co., P. O. Box 123, DeWitt Station; NORTH CAROLINA, Charlotte 5, M. F. Taylor Co., 1224 Dresd en Drive, West; OREGON, Portlan~ B, Don H. Burcham Co.,
P. 0 , Box 409B; PENNSYLVAN·IA, Hellertown, M. F. Taylor Co., 534 Ellen St. ; Lansdowne, M. F. Taylor Co., 275 Bryn Mawr Ave. ; PIttsburgh 36, M. F. Tay.lor
Co., 5436 Young ridge Drive; TEXAS, Dallas 1, Wyborny & Yount Co., 408 Merchandise Mart Bldg .; WASHINGTON, Seattle 99, Don H. Burcham C ~., 422 First
Ave., West.
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TAPE A MPLIF IER
G A NGED SWITCHiS
-------------------T------I
I
I
I
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RECORD
EQ UALI ZATIO
I
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REC II
:
REC
o
MPLIFICA TI O
STAGE
REC
o
PB
PB
PB
NOTE : SEE FIG . I FOR CONNECTION
OF THI S AM PLI FIER TO THE INPUT, O UTPUT, AND REC OR D/ PLAYBAC K HEA D.
O FFO
(PL AYBACK)
BI AS
OSC ILLA TOR
Fig . 3. Ele ments of a tape ampl ifier used w it h a singl e re co rd -playba ck he a d.
recording is compensated by an equal
error in playback.
But if it is one's intention to play
recorded tapes- commercial tapes or
those recorded on friends' machinesthen correct azimuth alignment of 90
deg. becomes imperative, and there is
no advantage in this respect over a
three-head machine, except for the fact
that there is less work in aligning one
head than two.
When a single head is used for both
record and playback, the playback requirements take over. That is, the
requirements are more exacting for playback than for recording. A head suitable for playback can generally he used
for recording, but not vice versa.
A prime requirement of the playback
head is a narrow gap. The narrower the
gap, the better is the high-frequency response, all other things remaining the
same (same tape speed, head quality,
equalization, and so on) . The slower
the tape speed, the proportionately finer
must be the gap in order to maintain the
same frequency response. Thus if a gap
of .0002 in. is adequate at 7.5 ips to
maintain response out to 15,000 cps,
then a gap of .0001 in. is required at
3.75 ips.
A narrow gap is not a prime requisite
of a record head. To the contrary, a
relatively wide gap-in the range of
.0005 in.- tends to be optimum. The
narrower the gap in recording, the more
difficult it is for the magnetic flux produced by the head to permeate the tape.
The tape acts as a bridge from one edge
of the gap to the other, so that the magnetic flux comses through the tape. But
if the gap and therefore the bridge (the
tape across the gap) are too narrow,
not enough flux travels through the
tape, so that the record head has to work
all the harder to impress the desired
amount of signal on the tape; the re-
sulting increase in signal requirements
raises the possibility of distortion. On
the other hand, it is claimed that the
increased efficiency of modern heads
makes it possible to record satisfactorily
with the narrowest of present-day gaps
(.00009 in.).
Playback heads produce a very small
signal voltage, on the order of a few
millivolts at the most, and generally
much less. Hence there is a very difficult
problem of keeping noise and hum 111
pedance is desirable: A certain amount
of audio voltage is . required to drive
audio current through the record head,
thereby generating magnetic flux and
impressing a signal on the tape. The
higher the impedance of the head, the
gTeater is the required driving voltage.
But it is more difficult to develop a lowdistortion signal at high voltage than at
low voltage. If the recording has low
impedance, the required driving voltage
is reduced, and the difficulty is avoided.
By the use of separate heads for recording and playback, the contradictory
requirements of each type of head with
respect to gap width and impedance can
be met. But if the same head is to be
used for both purposes, then compromises are evidently in order. Thus record-playback heads typically have an
inductance of about 0.5 henry, whereas
a head designed expressly for p layback
may have an inductance of as much as
2.5 henries, and therefore greater output.
On the other hand, a head designed specifically for recording may have an inductance of 50 millihenries or less.
At the same time, it should be recognized that the compromises entailed in
record-playback heads are not so severe
as to prevent quite good resu lts from
being obtained with them. But the p erfectionist, desiring the best possible results in the present state of the art, can
obtain even better results with separate
heads designed for each function.
Three-Head Machines
HALF- TRAC K HEAD
DIRECTION OF TAPE TRAVEL
Fig . 4. Azim uth angl e.
the tape amplifier sufficiently low to
permit a satisfactory signal-to-noise
ratio; the problem is substantially more
difficult than in the similar case of the
magnetic phono cartridge. To maximize
the signal-to-noise ratio, a high-impedance playback head is desirable, that is,
one having a large number of turns for
high voltage output. (If a transistorized
tape amplifier were used instead of one
with vacuum tubes, then current rather
than voltage would be the prime requirement; as yet, however, virtually all tape
amplifiers employ vacuum tubes, which
have a high input impedance, so that
voltage rather than current is the significant electrical quantity.)
On the other hand, for recording purposes a head with relatively low im-
30
Machines with separate record and
playback heads generally are in the semiprofessional and professional class,
where maximum assurance is required
that (1) the unit is in pi'oper condition
before the recording session commences,
and (2) that the recording is proceeding
satisfactorily during the session .
The three-head machine, with separate
amplifiers for recording and playback,
permits one to monitor the tape as it is
being recorded, as illustrated in Fig. 5.
That is, one can listen either to the incoming signal (which is about to be
recorded) or one can switch to the playback signal (which has just been recorded). The time difference between
o-......-~T O
RECOR D AM PLIFIER AN D HEAD
PLA YBAC K HEAD
C
PLAYBACK SIGNAL
OUTPUT
IN PUT SIGNA L
Fig . 5 . Monitoring p rOVISion in a tape
machine with separate record and pl ayback heads.
AUDIO
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•
JUNE, 1959
CIRCUIT COSTS!
Now one hi-fi amplifier tube-General Electric's new 6DZ7
--does the work of two!
E ver y inch counts in designing trim, compact hi-fi equipment. That's one
reason why a single new G-E 6DZ7 in place of two 6BQS's is headline news.
Now you can have push-pull amplification in one tube envelope !
And your circuit costs drop ! You save a socket, you save oth er components.
Helps you sharpen your cost pencil, to m eet stiff price competition .
With stereo, your savings mount still furth er. H ere two 6DZ7's, powered by
one heavy-duty General Electric SAR4, will take the place of four 6BQS's.
Speaker volum e and tone quality are fully maintained . . . see ratings at right.
Go modern in amplifier design, go one-tube, go G-E 6DZ7 ! Any General Electric
tube office listed below will be glad to give you further information .
200 Ma in Ave., Clifton, N. J.
{1 n Clifton) GR egory 3·6387
(In New York City)
WIsconsin 7-4065. 6, 7, 8
3800 North Milwaukee Ave.
Chicago 41, Illin ois
SPr in g 7-1600
11840 West Olympic Blvd.
Los Angeles 64, Calif.
Phones: GRanite 9-7765
BRadshaw 2-8566
ProgreS$ Is ()~r" Mosf Imporft1hf Protlut:.f
GENE RA L·•
. ELEe TRt~
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TWIN POWER PENTODE
TYPE 6DZ7
Max plate di ssipation,
per pl ate
Ma x total screen
diss ipati on
Power out put (Under
foll owing conditions:
Eb 400 v;
Ec2 = 2S0 v;
Ecl= - 11 v ;
E,jg= 22 v peak
grid -to-grid voltage)
=
13.2w
4.0 w
18 w, with
only 2.5 %
harmonic
distortion
witho ut
feedback
OTHER G-E QUALITY TUBES
FOR HI-FI AND STEREO
5AR4
6BQ5
7025
6CA4
6L6-GC
7189-A
7247
ROBERTA PETERS
tapes her 0"""
re
That alone is not
the reason ""hy
Here's W'hy
It's the best-engineered tape in the world
.. . gives you better highs ... better lows ...
better sound all around! Saves your tape
recorder, too - because the irish FERROSHEEN process results in smoother tape
'" tape that can't sand down you r magnetic heads 01' shed oxide powder into your
machine. Price? Same as ordinary tape!
the two signals is so small-roughly power ampli.fiers. (Th3 techniques of
about 1/6 second at 7.5 ips- that alter- testing will be discussed · in a later article. )
nate switching between them affords a
In the case of frequency response,
ver y accurate indication whether the
recorded signal is similar to the original there are two tests which should be
·ignal. If there is a noticeable increase made: (1) to ascertain whether playin distortion in the recorded signal, one back equalizatio n corresponds to the
can reduce the recording level. Con- standard curve, which is NARTB at 7.5
versely, one can increase the level if the ips; (2) to ascertain whether fiat remonitoring arrangement indicates no sponse is achieved when p laying a tape
perceptible increase in distortion. Simi- recorded on the same machine. While
larly, if frequency response of the taped the first test can be made as easily on a
signal sounds reasonably close to that of two-head machine as on a three-head
the original signal, the recording may one by using a' standard test tape and
proceed; if not, then the frequency re- checking for fiat playback response,
sponse of the tape recorder bears look- the second test is greatly facilitated by
ing into (which is the subject of a later three heads.
article). Ordinarily, one would not wait
A few of the better (and higheruntil a r ecording session to check fre- priced) two-head machines can match
quency response by the monitoring the performance of the three-head ones,
method. Instead, one would make a test at least to the extent where the differrun, using a phonograph record or FM . ences are inaudible, or negligible. The
program as a signal source.
advantage of the thrEe-head machine,
There are three basic tests required then, lies not in actual performance but
to ascertain whether the tape recorder in greater assu.rance of proper performis oper ating at its maximum poten- ance. Such assurance is obtained
tial for recording and reproduction of through greater ease of testing and
through greater ease of adjustmen t
sound. These concern the frequency response of the machine, distortion, and when testing reveals that something is
signal-to-noise ratio. A high-quality wrong.
The impOl'tance of periodic testing,
tape r ecorder, into which categor y most
three-head machines are apt to fall, con- and adjustment if necessar y, should not
tains adjustments for frEquency r e- be underestimated if high fidelity standsponse and permits one to adjust bias ards are in force. If the operator of a
current, which in tum affects both fre- tape recorder is interested merely in opquency response and distortion. The eration-whether mediocre, fa iT, 01' good
higher the bias current (within the nor- - that is one thing. But if he considers
mal range of adjustment), the lower is mediocre or fair operation as equivathe distortion, but also the worse is the lent to failure, then regular testing and
treble response.
adjustment become an essential part of
While one c:tn check frequency r e- the operating procedure. The professponse, distortion, and signal-to-noise sional and semi-professional recordists
check their equipment before trouble
ratio on a two-head machine by first
recording a tape with the proper sig- develops, not only after it happens. Siminals, rewinding the tape, and playing it larly, the audiofan desiring high fidelback, this is a cumbersome, time-taking, ity performance from his tape r ecorder
and somewhat inaccurate process. Each will try to head off trouble before it
time an adjustment is made, it is neces- spoils a r ecording session, often irresary to r epeat the procedure to learn trievably.
the result of the adjustment. W ith a
On the other hand, the importance of
three-head machine, where recording ease of testing a.nd adjustment depends
and playback are virtually simultan eous, upon the amount of use that the tape
one can check performance as swiftly recorder sees. A professional or semias in the case of control amplifiers and professional machine may be used many
FOUR-TRAC K HEAD
TRACKS I AN D 3
ARE PLAYED IN
ONE DIRECTION .
~TA-- - L.PE----.---li:--,~
~~::::;;:;~~~
_ _ _ .!. _L ___ ~
"""=
. I I
-- i
\
13NN'o'H:> lHElIH
I
I
I
GAPS
t::=~==R=IG=H=T=C=H=A=N=N=E=L~- - _J - ~ -- - -I~
~~~;:::=~::::~~~13NN'o'H:>
TRAC KS 2 ANO 4 ARE PLAYED
IN THE OPPOS ITE OIRECTlON,
AFTER THE REELS ARE REVERSED
A ND THE TA PE TURNED UPSIOE
DO WN.
A vai/able ,uherever qulliity tape i8 801d.
OR Radio Industries, Inc., Opelika, Alabama
Metropolitan Opera 8tar RobertaPeter8 i8 under the
exclusive management of Hurok Attraction8, Inc.
1~31
__ .1,;- ___
"l,
L_
I
,)
'-'
DIRECTION OF TA PE TRAVEL
Fig . 6. Four-track stereo tape .
32
AUDIO
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•
JUNE, 1959
AUDIO
•
JUNE, 1959·
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FOUR-TRACK HEAD
TWO-TRACK
TAPE
FOUR- TRAC K
TAPE
:(=~
LEFT
lH£)f~
LEFT
-l
H31
---t--t---~
1
1
--
RIGHT
----d
1
1
----L-t----,~
___L...! ____ ..l_
RIGHT
'
I
"l
......"""'---'"
hours a week, so that quick, easy checking and adjustment are imperative. But
in the home, a machine may receive only
a few houi's of use each week or each
month, so that facility of checking ··and
adjustment becomes relatively less important. For one thing, the smaller
amount of use means that trouble is less
apt to occur. For another, when trouble
does develop, there is apt to be less
urgency about curing it.
A disadvantage of a three-head machine, compared with a two-head one,
concerns azimuth alignment. Not only is
it more time-consuming ,to align two
heads instead of one, but more equipment is necessary.; Where a single head
is used for record and playback, an azimuth alignment tape is all that is
needed. But where separate heads are
employed, one needs in addition an audio
oscillator or other source of single frequeneies (such as a test record) in order
to align the record head.
A possible disadvantage is that due
to the oscillator. The frequeney of the
oscillator is usually between 30,000 and
100,000 cps, and the signal it generates
has the characteristics o~ a radio wave.
There is a problem of preventing this
wave from being picked up and amplified by the p layback amplifier, which is
a very high gain affau·. If picked up,
.,. the.. bias frequency signal can be amplified to the extent where, though not
audible in itself, it may cause malfunction of the playback amplifier by driving it to excessive distortion, 01' perhaps
1
I
I
I
I
I'
oIfolf---1.2S" --_.-l1
1-1
I
DI REc TI
Fig.
8.
Stereo
1
N OF
GAP
TAPE :AVEL
tape using
heads .
GA~
I
)
LOWER GAP SPANS UNRECORDED
SPACE ON TWO-TRAC K TAPE .
•
DIRECTION OF TAPE TRAVEl
I
I
1
Fig : 7. Result of
using a four-track
head to play a
two-track
stereo
tape.
stagg ered
by blocking the audio pl!1yback signal.
While commercial equipment employs
propel' shielding, layout, and other measures so that the problem ordinarily does
not arise, the amatem: builder who ventures upon construction of a tape amplifier containing separate record and playback sections for a three-head machine
PLAYBACK
HEAD
fore the individual may wish to -add an
extra two-track head so that he can ob-.
tain better resnlts when playing twotrack stereo tapes (or half-track monophonic ones).
If a four-track head is used to play
a two-track stereo tape, one section of
the head will partially span an unrecorded space on the tape, as shown
in F ·ig. 7. Therefore this section of the
head will produce less signa l output than
the other section, resulting not only in
deterioration of signal-to-noise ratio, but
also in lack of balance between the two
signals. This problem can be met by a
mechanical device that moves the fourtrack head up or down-up for playing
four-track stereo tapes and down for
playing two-traek stereo tapes. However, there is some danger of impairing
azimuth alignment as the head is moved
up and down. Thus the audiofan may
prefer to install an extra two-track
head, so that it and the four-track head
can eaeh remain in fixed position.
ERASE
HEAD
U
RECORD
HEAD
ERASED TAPE
FIRST PLUS
SECOND SIGN ALS
IMIXER
FIRST
SIGNAL
FIRST
SIGNAL
SECON D
SIGNAL
FIRST PLUS
SECOND
SIGNALS
RECORD
AMPliFIER
FIRST PLUS
SECO ND
SIGNALS
RECORD IST
Fig. 6. Four-track stereo tape.
may run into considerable difficulty on
this score. The author speaks here from
exp erience with one such tape amplifier
that he sought to build ; after his first
tl'y, he had' to teal' down the unit and r edesign it with respect to layout and
shielding.
Tape Recorders with Extra Heads
The introduction of four-track stereo
tape has brbught hew problems. As
shown in Fig. 6, ' two tracks are recorded in eaeh direction, so that a stereo
tape may be reversed just like a monophonic half-track tape. Obviously, each
of the foul' tracks is considerably narrower than those on a two-track stereo
tape, and the signal output of each section of the four-track playback head is
proportionately reduced, resulting in a
lower signal-to-noise ratio. If one plays
a two-track tape with a four-track head ,
there is an unnecessary sf.lcrifice in signal-to-noise ratio, because part of the
recorded signal is not picked up. Ther e-
Four-track stereo tape is associated
in the main with the 3.75 ips speed. As
previously pointed out, this speed requires the playback to have an extremely fine gap if frequency response
is to be maintained out to 15,000 cps
or thereabouts. But, as also pointed out,
the gap might be too fine to be suitable
for recording. Consequently, it may be
desirable to have an extra head for recording purposes.
Initially, the majority of stereo tape
machines- at least those for the home
- employed staggered heads for playback, spaced about 1.25 in. apart, and
positioned so that one operated on the
(Continued on page 45 )
_ __1
,~ ~-;
Comparison between ste re o recorq.playback he ads. Left, two-track (Shu re l'R--40 l;
right, four-track (Shure TR--481.
AJJO;lO' . •
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;.;-
JUNE, 1959
NEUMANN
KM-56 Miniature Condenser Microphone System
The lalesl 10 ioin Ihe precision Neumann line. With qualily in every way similar 10 Ihe
U·47 series, bUl its dimensions are amazingly minialurized.
Frequency Response: 40-15,000 cps ±3 db
Output Impedance: 50/ 250 ohms (must be specified in order)
Field Patlern: Swltchable on microphone: non-directional,
bl-dlrectlonal, and cardioid
Non-linear distortion: less than 0.8"1. entire range to 110 db absolute
Dlmenslons~ ' M~crophone: 1fa" dla.; 6" length
Power supply: 8!f2" x 4" x 4 3/4"
Weight: Microphone: 4 oz.
Power supply: 5 Ibs.
Operates on 115 volt 40-60 cycles. Sfa .27 standard thread Net $490.00
(omplele microphone syslem consisls of microphone, power supply (Iype NKM) inler.
connect cable (Iype K(·l) with Z-38 full elastic suspension, A( power cable. U. S.
fuse holder, pilol lighl, power conneclor, and XlR oulpul receplacie, with mating
cable connector.
KM·54a Miniature Condenser Microphone System
Net $460.00
(nol shown) Same as above bUl cardioid directional pallern only. lenglh: 43/....
KM·53a MI"lature Condenser Microphone System
Net $440.00
(nol shawn) Same as above bUl non·directional pallern only. lenglh: 4%.".
NEUMANN
M·49b Variable Directional Pattern Microphone System
This microphone permits remole electronic conlrol of Ihe directional
characlerislic. A smoolh, continuous fader·conlrol selects any of Ihe
basic directional pallerns (non·dlrectional, bi·directional, and
cardioid) and any inlermediale pallern. Wide frequency response
with exlremely low dislortion, 0.6% 40-Bkc up 10 110 db abso·
lule, a slighl roli·off of frequencies below ~O .cyl1es 10 prevenl
shock·noise inlerference, and exlreme ruggedness, make Ihe M-49b
Ihe ideal "work·horse" for sludio and remole recording, as well
as single·mike pick u~s f,rom concerl halls.
(omplele microphone syslem ' consisls of microphone, power supply
(Iype NN·48), inlerconnecl cable (Iype (,26); A( pawer cable, XlR
oulpUl conneclor, and MZ·49 swivel mounting harness: .
Harvey Radio Co., Inc., Industrial Division
Department BW
103 W. 43 St.,
New York 36, New York
We'll allow you $75.00 for each towards
the purchase of eacl}.. Neumann system
you select. Send those old mikes todcty.
Service 'to the Broadcast &- · F{~~oh;l.in(i Industries tor more than 32 YEi~:<,r'
Dimensions:
Weight:
Mlcropho"e: 3" dla.; 6 1/4" length Microphone: 1 34 Ibs.
Power supply: 8!f2" ,x.4" x' 4%" Power supply: 5!f2 Ibs.
Net $540.00
NEUMANN U-47 (U-48) "Studio Standard" Microphone System
The only condenser microphone in its ~rice range fealuring an eleclronically
.switchable directional characleristic.
Frequency Response~ 40-15,000 cps ±3 d~
Outpuf Impedance: 50/ 250 ohms swltchable'
Field Patlern: Swltchable non·dlrectional or cardioid
Non·llnear distortion: less than 1 % entire range to 110 db absolute
Dimensions: Microphone: 2!f2" dla.; 8" length
Power supply: 8!f2" x 4" x 4 34"
Weight: Microphone: 1!f2 Ibs.
Power supply: 4 Ibs.
Operate on 115 volt 40·60 cycles. Net $390.00
(omplele microphone syslem consisls of microphone, power. supply (Iype NG)
inler·connect cable (Iype U(-3) wilh Z·37 full elastic suspension', A( power
cable, U. S. fuse holder, pilol 'lighl, power connector and XlR oUlpul
receplacle wilh mating cable conneclor.
U·48 System Same as above bUl Field Pallern seleclable either bl.
directional or cardioid.
Net $390.00
~---------------------
I·
I
Please send us:
.. .. .. ..... M-49b
@ $540.00
................................ .. KM-56 @ $490.00
NEUMANN Type SM·2 Miniature Stereo Microphone System
Two separale and complele con.denser microphones and Iheir , respective pre'amplifiers In ' Ihe same minialure housing. The Iwo condenser .c'apsules are
mounled one above I~e 01 her, Ihe lop 'one being rolalable 10 achieve Ihe M·S
SIerea Recording Technique (also known as Intensity stereo). Each of Ihe Iwo
microphone syslems' can be separalely switched 10 any pallern (non·directional,
bi·directional, and cardioid) or anyone of six inlermediale pallerns. Specific a·'
ti~ns identical 10 KM-56 microphone wilh addition of exlreme balance belween
syslems, and numerous inlermediale directional pallerns.
(omplele microphone syslem consisls of microphone, power supply (Iype NSM),
inler·connect cable (type S(-I) with Z-42 full elastic suspensiGlf, A'E power
cable, XlR Cannan output connectors. \/. S. standard pilot Iighl, fuse , older,
A( receplacle.
( Dimensions:
Microphone: 1 !fa " dla.; 8" length
Power supply: 81f2" x 4" x 4 % "
Gentlemen:
We're sending you the following old professional
Weight:
Microphone: 9 1/ , oz.
Power supply: 5 Ibs.
Net $875.00
........ .. .... .. .. ... .... .... .... .. ... .. .. .... .. SM-2
@$875.00
.... ........ ....... ............. ... U-47
@ $390.00
............. ........................... .. :.... U-48
@ $390.00
.:.!..
Of course, deduct $75.00 from the price of each
unit that we've ordered because we've sent the
old "mikes".
Name ...... ... ..
Title ........ ..
.............. ................................... ', ..
I
Address:.
Company .... .. .................................................. .. ........... ....
.j"liMf.jlilii¥i,I'M,l;Iiii,lij;iol,liA".jjl'£{ij,il'Wid,j('ijli:!iiiiol:iiiM[ii'iilii:i~i,ij"iiMI:@l'ij:iljll:.Mi:n\i.jii'l['ii. j'iii"iit _
AtJDIO
35
. ' JUNE, 1-959
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Left, general view of Music Corner from
the fron t. The horn opening at the left
accommodates a JBL 375 tweeter and
acoustical lens. The control panel is fi tted
with edge-lighted Luci te panels, and the
tape and phono cabinet is shown with
doors closed, contrasting with the cove r
photo in which the doors are open .
Below, detail of cen ter un it, with amp lifier deck open, showing two Mcintosh
60-watt amplifiers. All channels are
switched at the t imer panel , and when
second channel is activated, the related
power ampl ifier and blower are turned
on .
Organ and Hi-Fi System
in Unique Combination
HEN R. G. SOHLBERG) 3035 E. California Street, Pasadena, Calif., conceived a "Music Corner" back in
1944, he gave considerable thought as to the best
method for achieving good bass from his speaker design .
The self-contained straight-horn approach was chosen in
p reference to corner folding, which brought with it some
physical ·and geometrical p roblems. The horn shown used
the J ensen " a ypex" design, calculated at every six inches
of the horn length. (Photos by J ay Russell, Ltd., San Gabriel, Calif ornia.)
W
AII · bond AM'FM
Radio abov e
Concert Organ
Compression
Chamber
Organ Bench
Above, rear of cabinets, showing component arrangement and wiring. Note
nea t ness of interconnecting cables- an
example worth studying by anyone e ngaged in hi-fi installation, ei t her for his
own use or commercially .
Boss
Horn
L ow Se c t
Low
TobIe
Upper Deck : Tuner, Preamplifier ,
Above : Phono
Clock and Switching
L ower Deck; Powe r Amp liJie r s
Below : Stereo Tope
Left, system la yout diagram . Spe ak e r
components used are those of the JBL
Hartsfield and Paragon enclosureswoofer, 150-4C, tweeter-midrang e , 3 7 5 ,
wi th
500-cps
crossover.
Additional
speaker, not shown, has similar matched
components exc~ pt that bass reflex c'a binet is used for portability and rearrangement advantages.
AUDIO
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e . JUNE,"
·1959
Juan Montero, matador.
>. .
From BULLFIGHT, by permission of
Simon and Schuster, Publishers.
Copyright ©1958 by Peter Buckle.y.
. . • for the matador - it comes
when he can no longer play at the
game of bravery, but must at last
face up to the ~upreme test of his
courage and greatness - when he
must conquer or be conquered.
paper claims, every brand, every
product of old must now face up
to the new challenge wrought by
stereophonic sound. Regardless of
past laurels, it is today's perform·
ance that counts.
• . . for the turntable or changer it comes when the stylus descends
to the groove of a stereo record, to
track as never before required ...
vertically as well as laterally, with
lighter pressure, greater accuracy,
'less distortion and far more sensitivity-when the operation must
be silent, smooth and flawless to
j>ermit the music to emerge with
clarity, purity and distinction.
The United Audio DUAL-I006
... totally new, significantly dif·
ferent ... is the only combination
professional turntable and deluxe
changer created for uncompro·
mised stereo and monophonic
reproduction.
We invite you to visit your author·
ized United Audio dealer ... to
submit the DUAL-I006 to the most
demanding of tests. ' .' to see and
hear )t in its "moment of truth~'
Shorn of pretension and mere
The DUAL-1006
com~ination professional turntable / deluxe changer for un compromised stereo and mono reproduction
Aetually traeks and operates automatieally or manually with only 2
grams stylus pressure.
Choice of heavy, large diameter
turntables· - new laminated concentrically-girded design retains
dynamic balance and plano surface.
Rigid equipoise motor suspension
principle eliminates vertical rumble.
Built-in direct reading stylus pressure/tracking force gauge.
• ''h lb • • tandard;
AUDIO
•
5~
Totally new design one-piece tone·
arm - provides perfect vertical and
lateral tracking - no muitiple arm
resonance or cartridge vertical amplitude distortion.
Truly freefloating tonearm - unique
clutch disengagement for complete
freedom.
Multiple transmission motor drive
uses individual gears for each speed
- automatic disengagement makes
"flat spot thumping" impossible.
Stereo· mono . switch has phase·canceiling feedback circuit to remove
vertical noise signal from mono records played with stereo cartridge.
Obsolescence-proof intermix for
present or future record sizes.
Elevator action changer spindle safeguards record grooves and centers.
True manual (or automatic) single
piay - permits setting tonearm on
rotating or motionless turntabie.
united audio
.. R O D U C T .
O~
DISTINCTION
Desk 7, 202·4 East 19th St., New York 3, N. Y.
Please send full details to:
NAME.......................................................................
ADDRESS .................................................................., .
CJTY ........................ ZONE ........STATE .....................
lb. optional at small extra cost.
JUNE,
1~59
37
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Ea UIPi'J\ Ef'I ~r
cE]
DUAL MODEL 1006
RECORD CHANGER
Offering a host of new features and a
convenient form of operation, the Dual
(pronounced Du-al) Model 1006 is the
latest record changer to be introduced to
the high-fidelity market. This unit employs
the center,dx<?,p p_rincJ1l.~e; ~,lth a sturdy
spindle which ~u
Ifthe-r\lco'rds but the
bottom ~;6ne t9~-be '
oed slightly so as to
remove all weight £rom t-he record to be
dropped-then the remaining records are
lowered into position £01' dropping the next
one.
The set-down position is determined by
a patented roller-feeler device, in which
two '- small rubber rollers are extended below the stylus and when the arm is lower,e d (at a radius of about 3 inches) the
arm is led outwards to the edge by one
of the rollers and as it reaches the outside,
it "fixes" the~' set-down position. Then the
arm raises again, the wheels retract, and
the arm lowers to_the record at the correct
place, regardless of the diameter-~e it
7,10,12, or 11% inches. Since the set-down
position is determined by the record itself,
records may be stacked ' in any order or any
diameter.
The pickup cartri~e is carried on a
molded - plastie,at~ which may be changed
readily-----:(ffi turninl '<a small knob on the
arm the plate practically drops' into your
hand-allowing for a smooth styling of the
al'm without discontinuity for a removable
head. Four separate wires are provided,
and the unit is equipped with two audio
output cables. For playing monophonic
records with a stexeo cartridge, the two
"hot" leads are shorted together by a
'switch located near the base of the arm.
The cartridge mounting plate will accommodate most. pickups, but because of the
f eeler rollers: ('~hich must clear the styluB
while playiilg and y;et must extend below
the stylus during the change cycle) some
stereo pickups cannot be use(l because 'Of
their height-among them being the ESL
and the Stereotwin.
Figure 1 shows the Dual 1006, and at
the front will be noted three push butt'Ons
-STOP, START, and REPEAT-which pr'Ovide a variety of operations. After putting on one record or a stack, one
simply pushes the START button and" the
unit starts, -plays the record (s), stops, and
shuts itself off, retracting the idler so there
is n'O pressure on the mot'Orshaft which
can cause "flats." If one wishes to stop in
the middle of a record, intending to start
again with that same record, one pushes
the REPEA'l' and STOP buttons. The arm
goes to the rest and the unit stops. To start
again, one pushes the START and REPEAT
buttons together, and the same record
is played again from the beginning. ~o
repeat the record after it finishes play·
fig. 1. "Dual" Model 1006 Record changer.
• "DUAL" Model 1006 Record Changer
• General Electric Stereo Classic Amplifier
Model MS-4000
• Connoisseur Type B Transcription Turntable
• Glaser-Stee,rs Record Changer Cover
• "Microlift" Pickup Arm Control
• Kingdom "Omega'l Speaker System
illg, press th e REPEAT button; to repeat
immediately, press REPEAT and START
buttous -simultaneously. To use manually,
put in the ShOI·t spindle, push the MANUALbutton (just back of the other three)
and place the arm on the record manually.
Except during the change cycle the arm
is freed completely by an ingenious clutch
arrangement.
Alongside the arm rest is a built-in
stylus gauge which is a- simple dial indicator actuated by a "w~ighing platform"
into which the edge of ' the arm is hooked.
This is a useful feature for those who are
likely to _use different cartridges because
it provides , an immediate check. On the
" u-ilit -we observed the indicated stylus force
aIJout 'half 'the actual value as measured
an independent gauge. Once checked,
- however; the built-in gauge could be used
as a guide.
The turntable used with the standard
1006 weighs 3 lbs. 9 oz. For those who
wish it, a heavier turntable is also available as an extra. Ball bearings are used
freely in the unit-double sets on both
axes of the arm, two in the motor, and the
usual turntable thrust bearing. The motor
is sturdy, and is fitted with a balanced
Totor, vacuum impregnated field coils, and
tightly staked laminations, which together
with the suspension ,used results in a
rumble level measured at -36 db, in accordance with the NARTB standard
method of measurement. This standard
specifies that rumble shall be rated in db
below 1.4 cm/sec stylUS velocity at 100
cps, wluch corresponds to- 'j- cm/sec at 1000
cps with stand-ard_ egy.alization. We made
this measurement in a simplified manner,
but the result approximates the NARTB
standard. We used a D & R Flutter and
Rumble test record, which has three bands
-3000 cps with zero per cent flutter, 3000
cps with 1.5 per cent flutter, and an un·
modulated band for the rumble test. The
3000-cps band is recorded at a level of 5.8
cm/sec, so by recording the output of this
band, and then taking a second reading
while playing the unmodulated band, the
difference can -be used to determine the
NARTB figure. 5.8 cm/sec is approximately 1.5 db below 1.4 cm/sec at 100 cps,
a.nd since we measured a difference of 34.5
- db, the standard v.alue computes to -36 db. _
~~e acceptable rumble 'for a reproducing
turnt~}:Jle is --'-35 db, in NA-RTB standards.
Flutter and wow measured at 0.25 per
cent, which is essentially inaudible. The
hum field from the motor, which in itself is
built to minimize hum fields, is further
sluelded by the heavy steel turntable, and
no trouble was encountered from this
source. The unit tracks reliably at 3 grams
stylus force, and actuates the trip consistently. Aside from b,eing attractive, the
Dual 1006 is also a good performer. F-25
by-
AUDIO
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•
JUNE, 1959
AUDIOMASTER
FM-R301
STEREOMASTER SM-RISO
Standard .- type amplifier with FM/AM
tuner, best suitable for home use.
With 3 Functions as Stereo, Monophonic
and High & Low Channel Amplifiers
"" True Hi-Fi FM reception from 80 to 108
megacycles
"" Indicator simplified
"" Rumble filter switch provided on front panel
"" Easy to use, very attractively designed
PIONEER's all-new STEREOMASTER SM-R150
is the most versatile amplifier for reproduction
of stereo - 45/45 records, stereo" tape.s _ and
stereo radio broadcasts.
SPECIFICATIONS
2-6AQSA, 2-6BA6, 6AU6, 3-12AX7,
2-6AR5, 5R-K16, 6E5M, 2-1NA9
Frequency Ranges I BC 535-1,605 Kc
SW 3.S-12 Mc
FM SO-lOS Me
. Fr.equency Response: 30-30,OQO cps
Output : 7.5 .W .
Inputs : lOW 5-30 mY
AUX 200 mY & up
HIGH 30-100";Y
TAPE 5-30 mY
XTAL SO-300 mY
Dimensions : 5 !"X 14 !" Xll i "
Circuitry :
Tubes I
Output :
SPECIFICATIONS
6AR5 push-pull
2 ampliAers
involved in one compact chassis
7 5 walls per channel for stereo
(15 walls for monophonic use) without
harmonic distortion
_
Hum: - 53 db b!>low maximum output on input
Frequency Responce , ' ::t 0.5 db, 20-;1O!QOO cps
._ :'0." _ Eq oalization:
Input,s :
RIAA & . N.ARTB - (NF type)
TAPE, PHONO (MAGNETIC & CRYSTAL), AUX
Channel Filter:
Crossover frequency 3.5 Kc 6 db/ oct
FUKUIN ELECTRIC
Otowacho, Bunkyoku, Tokyo, Japan
AUDIO
•
39
JUNE, 1959
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Pelformance
Fig . 2. General Electric Stere o Clossic Am plifier, Mod e l MS- 4000 .
GENERAL ELECTRIC MODEL
MS-4000 STEREO CLASSIC
AMPLIFIER
Each new amplifier which appears offers
its own features and advantages, and since
performance of most high fidelity units
is held to as high a standard as possible,
there is little to choose from except these
features and the over·all appearance. This
General Electric Stereo Classic amplifier,
Model MS·4000 is certainly attractive, and
the arrangement ::md functions of the controls is "comfortable" to use.
From the circuit standpoint,. each channel of this amplifier employs a feedbackequalized preamp stage using a low-noise
7025/12AX7, with equalization being
shifted for phono and tape head inputs.
Two I phono inputs are provided, and the
input selector is marked TAPE MONO
(Records), STEREO (Records), TUNER,
and AUX. Iu the MONO record position,
a separate input jack is fed into the A
channel only, but both channels may be
par alleled by the MODE switch. It appears
from the schematic that a change of a
jumper on the selector switch would connect both pr eamp stages to the monophonic
pickup so it would not be necessary to
move the MODE control, if the user wanted
this feature. This would apply to the AUX
input too, which is also monophonic, feeding the A channel. The TUNER input is
stereophonic. For playing monophonic
records with a stereo pickup, the two
channels may be paralleled by the MODE
switch, which also can reverse the channels. This switch is marked clearly to show
how monophonic r ecords are to be playedeither through the A channel (normal) or
through the B channel (r everse), or
through both in parallel. T his should be a
handy feature for those who find difficulty
in figuring out what switches to oper ate
t'J get a desired result. The SELECTOR and
MODE switches are at the left with the
large knobs as shown in Fig. 2. To the right
are five other knobs, all smaller, two slide
switches, and two holes in the panel through one can be seen the pilot light,
and through the other is a small-screwdriver-operated input level control for the
tuner input, ganged for both channels.
One slide switch controls the a.c. power,
and the other controls a high-pass filter in
both channels simultaneously.
The remainder of each channel consists
of a 12AX7 in a Baxandall tone-control
circuit, followed by a 6BABA (pentodetriode) in an amplifiel'-phase splitter circuit and a pair of 6973's as tetrodes in
the output stage. The B channel has the
normal 4, 8, and 16·ohm outputs, while the
A channel has normal 4 and 16-ohm outputs and a pair of termiuals labeled BA
and BB. These are connected to the B-ohm
output tap and ground through a DPDT
switch which serves as a phase changer in
the speaker line. This switch is at the back
of the amplifier. Again inspecting the
schematic, it seems that it would be simple
to change the internal connections so that
the phase reversing switch would operate
on either of the other two output impedances.
The 6973 output tubes are relatively
new, but are capable of 20 watts output
with distortion well below 1 per ceut, aud
the MS-4000 amplifier employs two pair
of them- resulting in a total output of 40
watts with the two sections paralleled, or
of 20 watb in earh channel.
The power supply is uuique in that it
uses two rectifier tubes- a GZ-34 working
from 350·volt taps on the power transformer and supplying voltages to aU circuits except the output screens, "hich are
fed from n 6X4 working from 250-volt
taps on the power transformer secondary
and iuto a separate filter circuit. The two
preamps and the two tone-control amplifiers
are fed with d.c. to the heaters, resulting
in a hum/ noise level measured at 54 db
below 1 watt on t he phono input and 64
db below 1 watt on th e high- level inputs.
Input signals for a I-watt output measured at 0.B2 mv ou the phono inputs, 0.73
mv on the tape-head input, and .046 volts
at the tuner and auxiliary inputs. Bass
and treble controls provide a r ange from
+ 13 to -17 db at 30 cps and from + 12 to
- 15 db at 20,000 cps. The rumble filter
introduces a progressive droop beginning
at 100 cps and reaching - B db at 30 cps.
The contour control provides a variable
shunt across the capacitors in a t apped
volume control circuit, and provide a
boost of 13 db at 50 cps when the volume
control is 20 db down from the top, and a
boost of 20 db when the volume control is
40 db down from the top. Two per cent
intermodulation distortion was measured
at 26 watts in one channel and 24 watts
in the other.
Over-all sound quality with the controls
fiat is clean and crisp at good room volume,
and the tone controls- of the variable
turnover Baxaudall type which we consider the most desirable of continuously
variable controls- give adequate changes
without introducing "chestiness" or "thinness."
The amplifier is compact for all its
power output, measuring 5% in. high, 15
in. wide, and 12 in. deep ( less knobs ) . It
is an amplifier which we would consider
"comfortable" to use.
F-26
CONNOISSEUR TYPE B
TRANSCRIPTION TURNTABLE
The recently introduced Type B Connoisseur turntable retains all of the good
features of the previous model, adds some
new ones, and has been refined in many
important particulars. Of the features that
are retained, one of the most desirable is
the speed-change control and vernier speed
adjustment which are at the left rear of
the motor plate and separate from the onoff switch, which is at t1)e front edge of
tlie plate. This eliminates the possibility
of selecting the wrong speed when turning
the power on . Th is model uses black knobs
fOl' these functions, but we prefer to reo
place the power knob with a cold water
faucet handle of the lever type (cold, beca use one can t hen imagine that the C
stands for ' Connoisseur; in France, of
course, one would use the hot water
hanule) .
The heavy cast aluminium (the Connoisseur is made in England) turntable is
retained, but there the similarity ends, apparently. The main turntable shaft rests
on a Tef. ~n thrust bearing, and the journal
itself is nn adjustable split bearing of
Grafion, n graphite-impregnated Nylon.
Fig . 3 . The new
Connoisseur Type
B turntable.
40
AUDIO
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•
JUNE, 1959
$129 50
Slightly Higher In the west
THEMl1;240
• 4
•
•
•
•
•
•
•
THROUGHOUT THE LAST 40 YEARS, PILOT has made it possible for every audio
enthusiast and music lover to possess the quality equipment most suited to his require.
ments. Now, PILOT announces another new stereophonic preamplifier-amplifier-the
240, rated at 30 watts total (15 watts per channel, music power). We are sure you will
agree that, featur.e by .feature, the new PILOT 240 represents the best quality valu~ in
its class. Designed and engineered to professional standards, the PILOT 240 includes:
independent tone controls - Exclusive Pilot ·TroLoK meehaniCJIlly locks the Bass controls together and the Treble controls
together, at your option, to permit simultaneous (ganged) ad·
justment of Bass and Treble for both channels.
Three pairs of high level inputs for permanent simultaneous
connection of FM·AM tuner, Multiplex Adapter and Tape Recorder.
Two pairs of low level inputs for permanent connection of record
changer and turntable.
Non-shorting inputs throughout permit recording and playback
using a permanently connected tape recorder without short circuiting the tape recording signal, or the necessity for changing
of plugs.
Direct tape playback facilities are provided by connecting the
tape head to one of the phono inputs. NARTB tape equalization
is prbvided at calibrated positions on the tone controls.
Amplifier terminals permit you to. connect a set of extension
speakers in another room. Front panel Speaker switch con·
veniently selects either th.e main or extension system, or both.
Electronic Crossover feeds low frequencies to Channel A and
high frequencies to Channel B for monophonic bi·amplifier use.
Loudness Switch modifies the frequency response for enhanced
listening at low sound levels.
•
Exclusive PILOT automatic shut-off switch enables .the record
changer, at your option, to turn off the complete system after
the last record has played.
•
Provides automatic cancellation of undesired vertical response
of a stereo cartridge when playing a monophonic recording, 'with
Mode switch set to Mono-and eliminates necessity for· separate
Stereo· Mono switch.
•
11 Front Panel Controls - Input ,Selector, Mode (including
Stereo Reverse), Dual TroLoK Tone Controls (Treble Channel A,
Treble Channel B. Bass Channel A. Bass Channel B). Stereo
Balance. Master Volume. Speakers. Automatic Shut-off. and
Loudness.
•
Specifications - Power Output: 30 watts total; 15 watts per
channel, music power (in accordance with proposed IHFM
standards). Sensitivity for full output: 3 mv for phono record
changer, phono turntable; 110 mv for FM·AM. multiplex. tape
recorder. Harmonic Distortion: 1%. Hum and Noise: 80 db
below full output. Frequency Response: ±1 db 20-20.000 cycles.
•
Dramatic design - brushed-brass escutcheon with 24K gold;
plated frame and heavy duty knobs. Supplied complete with
black vinyl·clad steel enclosure.
Price - $129.50 including enclosure.
Slightly Higher in the West
•
WRITE TODAY FOR THE COMPLETE PILOT STEREOPHONIC COMPONENT CATALOG
PILOT RADIO CORPORATION. 37-04 36th STREET. L. I. CITY 1, N. Y.
AUDIO
•
41
JUNE, 1959
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Fig. 4. Plastic record-changer cover
by Glaser-Steers.
possibility of sliding across several precious
grooves in the process.
This item is another which should be
standard equipment wherever a manual
tnrntable is used and where the user likes
to take good care of his records. Mechanically it is very simple-the spring-loaded
vertical rod is raised and lowered by a
Nylon cam on the hand-lever shaft, resulting in a smooth action without any backlash in its operation. The Microlift mounts
to the motor board at turntable chassis by
two screws.
F-29
KINGDOM "OMEGA"
SPEAKER SYSTEM
The adjustment permits compensation for -an attractive transparent solid plastic
wear, thus keeping the bearing at optimum cover for changer and records, as shown
for a long life. The adjustment is made in Fig. 4. Soft plastic covers, such as one
by adjusting the split busbing to the point uses for typewriters, may droop down on
where the shaJt is just free enough to lift the records while they are playing and
out of the bearing when the platter is cause speed variations or interfere with
lifted up. This makes an almost ideal bear- the challge cycle. The hard cover cannot
ing for this purpose, and results in very . do this, naturally, but with its- foam rubber
strip around the bottom it remaip,s in
low rumble content.
The hysteresis-synchronous motor em- place, clear of records and mechanism. The
ploys the same type of bearings, and the strip is also an effective sound deadener,
motor itself is very flexibly supported on
rubber mountings. The motor shaft is
stepped and tapered on each step to provide the vermer adjustment of speed, witll
a range of about ± 2 per cent on each of
the three speeds.
The idler wheel is quite narrow, and is
mounted on a plate which is also very
flexibly attached to the main chassis.
Another new feature is the stroboscope,
which is viewed through an opening just in
front of the turntable, which can be seen
in Fig. 3. The illuminated stroboscope disc
is mounted on tne underside of the platter
and is viewed through a mirror.
Using the technique described earlier,
Fig. 5. The Microlift, shown with an ·ESL
the rumble level of the Type B Connoisseur
arm .
was measured at 53.5 db· below a stylus
velocity of 1.4 cm/ sec at 100 cps-consid- and no needle talk can be heard when the
era.b ly better than NARTB standards. rover is in place.
This, together with wow and flutter of less
This is an excellent accessory and no
than 0.15 per cent, results in an excep- home that has an exposed record changer
tionally fine turntable for critical appli- should be without one.
F-28
cations.
Fortunately, the error of the earlier
stroboscope supplied with the Connoisseur "MICROLlFT" PHONO ARM
-which had the wrong number of lines in
CONTROL
the 45-rpm band-has been corrected.
In the days of six-ounce stylus forces
In physical specifications, the unit meas(yes, the old Capehut ..actually worked at
ures 131h in. from front to back, and it six ounces) it was easy to lower a pickup
is 15% in. wide; it requires a clearance of
t o the record gently because of the natural
3% in_ above the tope of the mounting gravitational resistance offered to the hand
board and 3% in. below.
F-27 by so much mass. Now, however, the 1- to
3·gram stylus forces make handling the
piclmp arm about as tricky as dropping a
GLASER-STEERS RECORD
dried pea into a cup from six feet up in a
CHANGER' COVER
high wind. The Microlift-another British
difficnlty.
The currE!nt treud for using components importa,tion-eliminates this
of a high-fi system in their own housings This de-v.c~, shown in Fig. 5, mounts on
often means that a record changer or turnthe main ' plate of a turntable adjacent to
table ' may be exposed to dust practically
the arm and raises or lowers the arm to
all of its natural life, and while tlle
the record gently and accurately. The
curved arm is adjustable for height, and a
changer itself could "take it," everyone
agrees that dust is not good for records quarter-turn of the actuating lever raises
under any circumstances. Furthermore, the pickup arm abont % in. at the point
when a changer is operated in the open, it of contact-which means abont 1h in. at
the stylUS tip. Since the lift is straight
is often possible to hear "needle talk"
throughout the music.
up and down, it may be used for cueing
Recognizing these problems, Glaser- with considerable accuracy, and the pickup
Steers has come up with a simple solution may be raised and lowered without any
One of the newest of the small speaker
enclosures in the Omega, introduced by
Kingdom Products Ltd. This unit, measuring 15 in. wide, 26 in. high, and ll1h in.
deep, offers excellent tone quality with a
remarkable r ange, considering its ~mall
size. The cabinet itself is made of 1 % -in.
plywood, well lined with rock wool, and
completely enclosed. Three speaker units
are used-one 12-in. cone and two 21h-in.
tweeters, together with two capacitors serving as high-pass filters for the tweeters.
Using Vol. 1 of the "King of Instrumants" series-in which a scale ranging
from 16 to 8000 cps is played on an organ,
-the sounds during the lowest octave appeared to become musical at B, approximately 31 cps.
Because of the heavy cabinet construction, the low-frequency performance compares f avorably with more costly units . .M
the upper end, usable output was heard
up to 13,000 cps, and measurable output
was noted to 16,000.
The Omega is fiuished in various woods,
with the oiled walnut model giving the impression of high-qnality furniture . . The
grille covering is modern in design, and
the over-all appearance would fit most
decorative schemes satisfactorily. The
placement of the high-frequency speakers
-one at each side of the center·mounted
woofer-makes its possible to use the
speaker either vertically or horizontally.
F-30
Fig. 6 . Kingdom "Omega" speaker system.
AUDIO
42
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•
JUNE, 1959
.
1
A
CONQUEST OF
The Harmony
Trio Speakers
Here is a complete three channel stereo speaker.
system - better than you have ever heard at
any price - which gives the full stereo effect
in every part of any room. And yet it consists
of only two booksize speakers and a hideaway
bass that is completely concealed from view.
Sound impossi~~e? 'Yell it was, until Weathers
developed the Harmony Speakers utilizing the
principle of Variable Mass.--'-the first major
breakthrough in speaker design in twenty
years. Now spac: .n~~4,'E() longer be
a barrier to speaker performance.
Stop in at your dealer
and see why.
System
Features:
Made in U.S.A .
Patent Applied For
Three channels. A full range
speaker for each of the stereo
channels and a non-directional
Hide-away bass. The smallest and most
efficient stereo speaker system available.
Fits any size room. Blends
with any decor.
Component Features,
Harmony Speaker.
Size : 11/1 x 9 v.. /I X 3 %II •
Response: 70 to 15,000 cycles.
Finish: Black leatherette. Golden grille.
Hideaway Bass.
Size: 16Y2/1 x 16Y2" X 5Y2/1.
Response: 30 to 100 cycles.
Finish: Ebony,
. Individual Harmony Speaker $29.75
'.
Hideaway Bass $69.50
Complete System:
Harmony Trio $119.50
OI VIS I ON
OF
AD VA NCr::
'''lDU aTRII!:S.
INC: .
66 E. Gloucester Pike, Barrington, N. J.
Export: Joseph Plasencia, Inc., 401 Broadway, New York 13, N. Y.
- AUDIO
•
43
JUNE, 1959
"
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Recording the plzzrcato movement 0/
the Bartok after a long, grueling session
to determine recording techniques most
suitable for the special problems involved.
It is 3 :00 A .M. the day 0/ the concert.
LIVE V8. RECORDED CONCERT at CARNEGIE
RECITAL HALL
On
January 10th, 1959, a "Live vs. Recorded" concert was given
in New York City; protagonists were the internationally famous
Fine Arts Quartet and a pair of AR·3 speaker systems in stereo,
driven by Dynakit preamplifiers and Mark III amplifiers.
At pre-determined intervals the members of the Quartet would lay
down their bows, allowing reproduced sound to substitute for the
live music. After a minute OT so they would take over again "live"
without interrupting the musical continuity. (A carefully
synchronized stereo tape had been made the night before in the same
hall by Concertapes, Inc., for whom the Fine Arts· Quartet records
exclusively. )
Excerpts from reviews of this concert appear on the facing page.
Leonard Sorkin, /irst violinist 0/ the Fine
Arts Quartet, listens critically to trial
recording.
The formal concert, during one of the "live" portions
Advertisement
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upper half of the tape and the other on
the lower half, as illustrated in Fig . 8.
A substantial number of recorded tapes
were sold for the staggered-head arrangement. The individual who invested
in staggered tapes may be loath to
write off this investment, preferring instead to add another playback head in
order to be able to reproduce his staggered tapes correctly. Thus he would
have a stacked head for playing conventional stereo tapes, and he would
use one section of this head together
with the extra playback head to reproduce his staggered tapes. If he were to
~alf-track
monophonic
TR-35l.
head
(Sh ure
play staggered tapes with a stacked
head, there would be a relatively enormous lack of synchronization between
the two channels. The discrep ancy
would be 1/6 second at 7.5 ips, whereas
a number of experts consider that the
two channels must maintain synchronization within .0001 second for propel'
stereo effect.
The recordist wishing to achieve special effects may have to add one or more
heads to those already on his tape ma-
ERASE
HEAD
./
U
UNRECORDED TAPE
chine. Two of the best known of these
special effects are sound-on-sound and
echo effect.
In the case of sound on sound, it is
necessary to place the playback head
before the erase head, as shown in Fig.
9. The sequenc~ is aSf follows. The first
recording is made. The tape is rewound.
The recorded tape is reproduced by the
playback head, and this signal is monitored by the performer by means of earphones. ' At the same time the performer
makes a second recording. The first signal (from the playback head) and the
second recording signal are combined in
a mixer and fed to the record head.
Meanwhile, the tape has been erased
by the erase head. The clean tape that
reaches the record head receives the
combination of the first and second
signals. This process can be repeated as
Illany times as desired j however, noise
on the tape will increase each time, so
there is a limit to the procedure. While
it is not strictly necessary to add an
extra playback head for sound-on-sound
reco rding, it is quite inconvenient to
have to transfer the playback head
from its normal position (following the
erase and record heads) to a position
hefore the erase head each time that one
wishes to create this . special effect. Accordingly, the individual who plans to
do an appreciable amount of sound-onsound recording customarily will add an
extra playback head prior to the erase
head.
Figul'e 10 illustrates how the tape recorder may be used to achieve an echo
effect. Part of the signal picked up by
the playback head is fed back to the
record head, and is therefore repeated
in the manner of an echo. One can obtain superior results, more akin to the
natural echo, by adding additional playback heads, each one feeding part of the
signal back to the record head. The
amount of signal fed back IS decreased
at each successful head.
.IE
RECORD
HEAD
U!
INPUT o---~
PLAYIIACK
HEAD
U
r
RECORDED TAPE
(Larry Zide)
"When I wasn't looking I was never quite
sure which was which . . . . Directly after
[the movemen~ from the Bartok quartet]
the audience ~as informed that except for
the first eight bars ... the whole had been
recorded. I must confess that I was com·
pletely fooled."
AUDIO
(C. C. McProud)
'~The program notes for the concert suggest
. that .. . if the audience cannot detect the
switch overs, the demonstration would be
successful. By this criterion we would have
to say that it achieved ' at least 90 per cent
of success."
,
high fidelity ,
"The [listeners] up front were able to dis·
cern an occasional difference during transi·
tions from live to recorded sound, while the
deception was essentially complete for the
man farther back ... But during the pizzi·
cato movement from the Bartok ... source
location seemed to make no difference; the
recording fooled just about everyone."
WOtrgtn (futning
~tcorb
(Stuart Davis)
"Only by observing the musicians was it
possible to detect the switch . . . The repro·
duced sound was so like the original it was
difficult to believe."
The ultimate test of sound reproducing
equipment, we believe, is its ability to
stand up under an "A-B" test in which
"A" is the real thing. The influence of
dramatic but unnatural coloration is
automaticalry eliminated, and faithfulness to the original sound becomes the
sole standard.
The speaker systems and amplifiers
used in this concert were designed for
the highest quality possible, limited
only by the present stale of the art.
Descriptive literature is available for
the asking from:
~-_~OUTPUT
DYNACD, INC. {Mark 111 amplifier kit
617 41st. St.
Phila., Pa.
ATTENUATOR
Fig. 10. Method of producing an echo effect in recording.
AUDIO ' .
JUNE; 1959
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Preampli./ier kit
Siereo C01llrol kit
ACOUSTIC RESEARCH, INC.
24 Thorndike St.
Cambridge 41, Mass.
$79.95
534.95
512.95
{AR.3
speaker
sySlem
S216.00
'AUDIO ETC
(from page 12)
".-<- ".
facturer, of course, would use it as original
amps died on"me, so soon, I got myself 'into n finished unit. We figured out the probone of my' obstinate moods. Obviously, able cost of the components in the two eqnipment.
Cost of the parts' For the audiofan,
pilots are impractical, or thcre would be pilot light systems at the manufacturer's
pilot lights. But they ought to be practical price and if we are right, there just isn't the conversion of the Regency HFT-IA to
and, by golly, I'll find out for sure whether any excuse for not incorporating these neon pilot operation costs $3.93, as we did
including the 67% volt battery (Burgess
they are or aren't, before I waste any cash lights into all future production of battery it,
UX45 or RCA va 318) at $2.07. The new
on replacement batteries, thank you.
Well, I have a consultant-assistant to transistor units, even fairly cheap designs. switched volume control cost $1.37.
For Regency, to bnild this little neon
help me in just such matters, name of Our cheaper pilot system, for instance
(with the 100-hour battery life for the " pIlot into its all-transistor unit, the cost
Ray Prohaska_ I asked him. We.,talked. We
investigated. We argued, for some weeks lamp) would cost Regency roughly 40 of additional parts would be around 96
on and off. He got down to work and came cents extra in parts. No more than that. cents higher than the present costs, as
The better system, with semi-infinite bat- above.
up with facts and figures-and I said, go
ahead. We were off on a fine chase. Two tery life, would cost , a..ll of 96 cents per
chases.
'
unit, over and above present parts, in facIncandescent
-~., llet"1'elftiU" is ;Ahat right now I have
tory production. ..
in op~iltion two".'ex~'nent battery-operated
Either one .of our two systems could be
Conversion B, just for comparison, was
preamps both of widCh·--baNe-q-eal, honest- incorporated •. into the present Regency via a low-voltage ~c!lndescent bulb-we
to-goodness, highly visible pilot lights, that HFT-IA production, Both work. The val- wanted to see what could be done in this
go on and off with the regular power
fashion, since the system is simpler and
d#
the parts cost less, notably the battery secswitch. Regency, prepare to quail. The ues are iuerent, though, in terms of first
cost and of battery life, as well as the tion, two ordinary low-voltage flash cells.
idea works!
The pilots"are, of course,. battery'oper- space. for ~he extra .components. One of Wa.! there a "flashlight" bulb that would
ated. But ln~ don't drl!-in ' the regular our p~ots IS a . flashlll~ neon lamp. ; The I, " draw a low enough current to be practical f
power supply; we usea;:"- eitta battery power other IS a contlllOOus mcandescent hght. There was. Ba.tteries.' , W-e lUst made it
for the indicators. The lights will last
(30¢), as to space.
plenty long enough for anybody's needs.
We used the GE 49, a low-drain type
Flashing Rhythms
One of the two types we tried will burn,
bulb, but oddly enough, it turned out that
as we figure it, for about a hundred hour~
Conversion A, the best ill my estima- this bulb was too bright for optimum
in normal hi-fi operation, with the usual tion, is the neon light job. It costs mort! pilot use-it was' ugly and too prominent,
rests between playing" periods. But the
as well as causing a too-high drain. Our
other type (which turned out to be the to install but lasts much longer and oper· first set-up would have lasted for roughly
most visible) lasts literally thousands of ates more cheaply, in terms of battery life. 25 hours of operation before the two "C"
The gadget makes use of a very simple batteries gave up- their ghosts-not bad,
hours without battery 'replacement-the
relaxation circnit (Prohaska's idea) that except for the inconveninence of the batshelf life of the battery itself. Once installed, it operates practically for the life turns the neon bulb on and off to save tery change. But after a 15-ohm resistor
current, in somewhat the fashion of those had been added, the bulb glowed with just
of the. preamplifier. How about that!
The pay-off is that these pilot lights portable street warning lights we see at the right amber light and , the battery life
don't cost much, even for the home gad- night, though my Rasher goes at a much
was increased to a probalbe one hundred
geteer who makes his own conversion at faster rate. The NE 51 neon lamp was hours and the bulb life to infinity.
audiophile prices. The more expensive con- mounted neatly through a small hole be·
At three hours of hi-fi a day, this pilot
version of the two-the long-lasting one- tween the treble and level knobs and just would operate, then, for roughly a month.
will cost him in parts less than the replaceIt would tell you, of course, when its batment of a set of ,}>urnt:out.,llDWer batteries. below; when the Regency preamp is teries were dead and you . ,w.ere left unNow I ask you, iB-,':t!a conversion that will turned on (again Via the volume 'control protected. New batteries, installed in a
preserve your main batteries for their full knob), it flashes a fast, dim but insistent few minutes, would cost 30¢.
useful life, and is good for a year or two "purr," at, I guess,. perha:ps fifteen to
The 'first cost of this simpler conversion
without being touched, worth the cash for twenty flashes per second. The values for would be lower; for the home gadgeteer
the flashing speed are adjustable within it would take only $2.55 to buy the parts
anybody'
Sure, if you're one of those seven-day certain limits, amounting to circuit satu- we used, including the same replacement
wonders, who never make absent-minded ,ration in one direction.
volume control with the extra switch.
mistakes, you won't need a pilot at all.
For the manufacturer-for RegencyThat speed adjustment was important
You'll save money. But who's a seven-day for me, and we discussed it at length be· our incandescent pilot light would add a
wonder' If we all were, there wouldn't fore arriving at a musically ideal flash
mere 40 cents to the cost of the parts in
need to be any pilot lights anywhere.
the HFT-IA preamp. That would seem to
For the manufacturer, of course, the cost rate. What was vital was that the flash
be peanuts, to put it mildly.
of such a pilot light is far less-he installs rate should not produce a visual rhythm,
However, the less obvious values here
the extra parts in the first place, without to interfere with music listening. At slower aren't so favorable. It's a touch and go
having to replace those already ~~t .mto flash speeds, such a rhythm would defi- propositiDn. You can have longer battery
nitely be set up and the sight would be life at negligible cost via larger and/or
.. ":: (A)
unpleasant for any music listener. Things more 1 % volt cells-but the space they
would be far worse, with two units flash.
take and their weight are unsnitable, in
ing slightly out of phase!
'
miniature units. (We barelY .,crammed the
The fast blinldng- that we achievlld is two"C" cells into the Regency.) , A:n~you'd
easily . visible as a pulsing mot on brit.· is still have . to change -the batteries' after a .
definitely too qnick, to produce any sort of couple of months or so in most situations.
rhythm. It catches your eye remarkably The bulb itself probably can't be improved
well, but it is not unpleasant to watch. In· upon in the incandescent area.
This isn't the optimum system, in spite
deed, this little blinker is the best pilot
EXTRA SWITCH, GANGED
of simplicity and low initial cost.
light I've evt;ln seen, bar none.
2-1.SV"C"
Lifef Around 2000 hours for the neon
bulb, and the shelf life of the 67% volt Practical Values
battery-one to three years of operation.
The higher first-off cost of the neon bulb
Cost of operation, in terms of battery life. system will sound bad to the manufacis around a tenth of a cent an hour (Cur· turer even. at a mere 96 cents, to eqnip the
Regency ,preamp: But look what you get!
rent drain is about O.Lma.)
Our conversion' involved the components The neon is bound to win on -points, when
for the relaxation circuit itself, the bat- you take a second look, in spite of higher
(8)
tery, the bJllb. ~d its hole and mounting, cost.
(1) You get a positive,'handsome, efplus an extra switch on the volume con·
fective warning signal that will operate
trol. We replaced the original volume control with a new one of this sort; the manu(Continued on page 72)
, .VP
46
AUDIO - .
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JUNE, 1959
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,I
Standard Methods of
Measurements for Tuners
The complete text of IHFM-T-l00, adopted in December, 1958
TWO PARTS-PART 2
5.00 Requirements and Characteristics
of Testing Apparatus
6.09.09 Spurious Response
With the tuner tuned in turn to each
of the test frequencies, the signal gener·
ator shall be continuously varied over a
wide frequency range to discover .if the
receiver is simultaneously responSIve at
frequencies other tha~ the test fr~queney.
These other responsIve frequencIes al"6
called spurious-response frequencies and are
most often found in superheterodyne receivers. Each spurious-response frequency
is noted and the spurious-response sensitivity test input is measured as in the
usable-sensitivity test except that the tuner
output with no .generator modulation shall
be adjusted to the same output as obtained in the usable-sensitivity test with
no modulation. This is because the generation of these spurious responses with the
tuner may involve a change in observed
signal deviation. The ratio of the generator output for spurious-response measurements and the generator output required
for the usable-sensitivity test for 30 db
usable sensitivity may be computed and
expressed in decibels. This is called the
spurious-response ratio. This test is properly classified as a selectivity or interference test, although its procedure is that of
a sensitivity test. Care shall be taken that
the harmonic output of the signal generator
is attenuated sufficiently so that it does
not affect the observation of the spurious
responses of the reeeiver_
Two partieular spurious responses are
not covered by this test and will be treated
separately.
(a) Image Response
A superheterodyne tuner is generally
responsive to two frequencies whose
differenee from the loeal oscillator
frequency is equal to the intermediate frequency_ One of these is
the desired signal frequeney and
the other is the image frequency.
This is a special ease of a spuriousresponse frequency and is tested as
sueh. Its observed eharacteristies
are referred to as the "image-sensitivity test input" and "image ratio."
The result shall be expressed in
decibels and is to be performed at
a signal level eorresponding to a 30
db usable sensitivity.
(b ) Intermediate Frequency Response
Another special case of the spuriousresponse frequeney in the superheterodyne reeeiver is that due to the
sensitivity to an intermediatefrequency signal input. The test
proeedure is the same as for the
other spurious responses exeept that
the input is adjusted to the intermediate frequency. The observed
characteristics are referred to as
the "intermediate-frequency-response
sensitivity" and the "intermediate-
frequency-response ratio." The results shall be expressed in decibels.
6.03.10 H1t1n and Noise
Hum and noise of the tuner are produced in two different seetions within the
tuner. One of them is the audio-frequeney
cireuitry following the volume or level eontrol. Hum and noise is measured as the
residual output of the tuner with the levcl
or volume control set to the condition of
minimum output. The results are expressell
in decibels below 1 volt and are not
weighted.
The other causes of hum and noise are
found in those seetions of the tuner aheall
of the volume or level control. For this test,
the total output of t,lIe tuner is measured
when the tuner is tuned to a signal of 1000
microvolts at 98 megacycles and the generator is not modulated. The results are
expressed in decibels below the output obtained with standard test modulation.
6.09.11 Frequency Drift
This test is intended to show the variation of the tuned frequency of the receiver. The tests are normally performed
with the receiver tuned to the standard
mean carrier frequency and the controls sct
to their normal eontrol settings (automatic
frequency control set to minimum frequency control). The variation of frequency is observed with the aid of a beat
signal obtained between the signal generator and another oscillator of constant
frequency. The frequency of the signal
generator is adjusted so that the receiver
is correctly tuned. This beat frequeney
may be measured and recorded. Alternate
methods of measurement are possible but
tI!e primary measurement shall be a measurement of the change in frequency of the
signal generator. One of the .alternate
methods is to obtain a calibration of detector d.c. output voltage with variation ill
frequency. Detector output voltage is measured and the corresponding frequeucy
drift is recorded.
The test shall co,er the following
causes of frequency dlift and th~ results
shall describe the operating eondir:ons:
( a) The frequency varies with time
during the warmup period of the
receiver. A curve of frequency drift
with time is plotted with time in
minutes as abscissas on a logarithmic scale and frequency drift · in
kilocycles as ordinates on a linear
scale. The time is measured from
switching the tuner "on," with observations started one minute later.
The warmup drift in kilocycles shall
be stated as the maximum drift
observed during a two-hour period.
If the tuner is intended for different
types of installations, these tests
should be repeated for the different
thermal environmental conditions.
(b) The frequency varies with powersupply voltage in a manner that depends upon the r~te of variation of
this voltage. The line voltage shall
be varied from 105 to 125 volts and
the resultant frequency drift shall
be observed one minute after the
voltage· change has occurred. The
amount of frequency drift for a line
voltage change from 105 to 125
volts shall be stated.
(c) If the receiver has automatic volume control, the variation of signalinput power affects the oscillator
frequency indirectly by way of the
control circuit. The frequency drift
with variation of signal-input ;voltage is to be observed after the receiver has been in operation a 'iufficient length of time to reach temperature stability. The maximum
frequency deviation from the signal
required to obtain 30 db usable
sensitivity to an output of 100,000
microvolts of the signal generator
shall be recorded.
The rated frequency drift is defined
in section 6.03.13.
6.03.12 Radiation
Radiation of the oscillator and other
circuits shall be measured in accordance
with the IRE Standards 51 IRE 17S1, 56
IRE 27S1, and their supplements.
6.03.13 Automatic Frequency ControZ
If the tuner is equipped with automatic frequency control circuits the test of
Sections 6.03.02 Usable Sensitivity, 6.03.04
Capture Ratio Test, 6.03.07 Frequency Response, 6.03.08 Distortion, 6.03.11 Frequency Drift, shall also be measured with
the automatic frequency control set for a
condition of maximum frequency control.
The pull-in range of the automatic frequency control is defined as the frequoncy
difference between the signal-generator
frequency and the tuned frequency of the
tnner which is required to reduce the tuning error to a value of 22.5 kc. This test is
to be performed at a signal generator output corresponding to 30 db usable sensitivity. The signal generator output is first adjusted and then the local oscillator
frequency of the tuner is measured as in
6.03.11. Care shall be taken that the tuner
has reached thermal stability. Th~n the
signal generator is to be tuned to a large
frequency difference and is slowly varied
toward the tuned frequency of the tuner.
The frequency at which the tuner is mistuned by 22.5 kc is recorded and the correct
tuned frequency is recorded also. The
frequency difference is the pull-in range of
the tuner. This test is to be repeated for
positive and negative frequency differences
and at levels of 20 db above the previous
test signals.
It may be desirable to repeat Section
6.03.05 Seleetivity Test with the automatic
frequency control set to condition of maximum control.
The rated frequency drift is the
ma.'rimum frequency drift value obtained
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,.3 tthe standard mean carrier frequency 111
7.04 Sensitivity Control
the tests of· 6.03.11 or 6.93.13. The setting
Many receiver . characteristics are afof the automatic frequency control must be
fected by the setting of the sensitivity COJlstated.
trol 011· a: tuner having such a control. For
6.09.14 Squelch Control
. - initial tuning and performance tests the
If the tuner is provided with an adseIlSitivity control shall be adjusted to giyC .
justablesquelch control, the output voltage
the highest simsitivity. To determine the
of the tuner is observed with the tuner
effect of the sensitivity controls, tests
tuned to the mean carrier frequency and whose results are affected by its setting
the signal generator modulated with stand- shall also be performed at other settings.
ard test modulation. The signal generator
7.05 Performance Tests
output is decreased from a large value to
7.05.01 Tuning Range and Frequency
a value of output at which there is a 3-db
Calibration
.
difference in audio output voltage when
The tuner tuning control .is set for the
the squelch control is turnea. from minimum respective minimum and ntaxilnunlcarrier
to maximum. The signal-generator output frequency in each tuning range which the
voltage is recorded~ The signal-generator tuner is capable of receiving with normal
output voltage is further reduced until a
operation. At each setting, the signal gen30-db difference is found. This value of erator is tuned to the resonant frequency
generator output voltage is recorded also
of the receiver and the ·carrier frequen('y
and the results are expressed in decibels recorded. This procedure may be extended
and are called "differential squelch sensi- to obtain a frequency calibration of the
tivity." The mean signal generator output ..:dial, if this is required. If any error in
voltage is also recorded. The result measfrequency calibration is found the error
ured in microvolts is called the "squelch maximum in kilocycles shall be stated.
7.05.02 Usable Sensitivity
threshold level."
The measurement of hum of Section
This test is performed at each of the
6.03.10 shall be repeated with tuners hav- standard test frequencies with the signal
ing an automatic squelch control circuit generator connected to the tuner under
with the squelch control set to position of test through the standard 200-lI-lI-f dummy
-m=imum control and the signal generator
antenna. -The signal generator shall be
having no output (zero microvolts) at the
amplitude modulated with standard test
tuned frequency.
modulation. The controls of the tuner shall
b.e set ~o the. normal control settings. The
7.00 Test Procedures, AM
SIgnal mtenslty shall , thim be reduced to
the least value which will.provide a 20-<1],
7.01 Normal Control Settings
Unless otherwise specified, all controls rise in indicated output with standard test
mo<1ulntion as compared with the iiidicated
on the tuner shall be set to their nOrnIal
settings. The volume, or level, control shall output with standard test modulatioJl
measured through a 400-cps null filter. This
be set to the position of maxinIum audio
output (see also section 8.01). The auto- . test serves to indicate the relative freedom
of the tuner from objectionable internal
matic frequency control shall be set to the
condition of minimum frequency control. receiver noise during pauses in modulation
The squelch control shall be set to the C011- when receiver noise is least likely to be
dition of maximum sensitivity, providing masked by modulation.
The results are expressed in microleast suppression of tuner noise. With the
volts.
exception of the selectivity control, all
. If the tuner is equipped· with a selecother controls affecting audio frequenc:v
response.shall be set to the condition of tIvity control or a ,sensitivity control or
flattest frequency responSe as indicated by .both, tliis test is to be repeated with all
settings of these controls if step-type conpanel markings.
trols are used. If continuous controls are
7;02 Tuning Control
used, this test is to be performecl at the
A tuner is tuned to a desired signal when minimum and maxinlUm settings of these
the tuning indicator shows correct tuning controls..
with the generator modulated with stand7.05.09 Volume Sensitivity
ard test modulation, and the selectivity
This test is performed at eacli of the
control in the position giving maximum
standard test frequencies with the signal
selectivity.
generator connected through the tuner
If a tuning position is found giving minunder test through the standard 200-IlJl.!
imum (audio) high-frequency response, the
dummy antenna. The signal generator shall
frequency difference shall be stated. If no
be amplitude modulated with standard
tuning indicator is incorporated in the
test modulation. The signal generator shall
tuner, or if no usable indication is obb~ adjusted for an output of 100,000
tained, minimum (audio) high-frequency
response shall indicate proper tuning. mIcrovolts. The output voltage of the
tuner shall be recorded in decibels with
Tuning for minimum (audio) high-frerespect to 1 volt. Then the signal generator .
quency response isperfor.med_ by ·:first
tuning appr?xinIately an~ t!Ien increasing . output 8~all be reduced to a. valiieat wbich .
the ·audio output (if the tuner has ·been
the modulatmgfrequencyuntil the audio
reduced by 20 db. ·
.. .
.
output has decreased 14 db. The tuning
The results .!;!!... the. volume sensitivity
control is then finally readjusted S'}ightly
for minimum audio output.
. tests are expres.s ed in ·¢icrovolts.
If the tuner is eqUlpped with either a
It is recommended that the tuning conse~ectivity or asensitivify control, or both,
trols be adjusted at an input level corresthIS test shall be ,repeated for all settings
ponding to the usable sensitivity test input
of these contrqJs;,jf:step-type controls are
giving 20 db usable sensitivity. See Section
3.04.
used. If continuous coiltrols are used, the
test shall be made for· the minimum anel
7.03 Selectivity Control
maximum settings of these controls.
Many tuner characteristics are affected
The rated sensitivity of a tuner shall
by the setting of the selectivity control on
be equal to the highest number of microa tuner having such a control. For initial
tuning .and performance tests, the selectiv- . volts obtamed in all tests of sections 7.05.ity control shall be adjusted to give the .. 0.2 .and7.05.03-with·the controls set to their
highest degree of selectivity. To determine normal settings. .
7.05.04 Selectivity
the effect of the selectivity control, tests
whose results are affected by its setting
The tuner is tuned in succession to
shall also be performed at other settings.
each standard frequency as in the usable-
50
sensitivity test. The signal-generator output voltage is adjusted for a 20-db uljablesensitivity test input, The signal generator
is then detuned 10 kilocycles each side- of
resonance, and the output voltage of tlle
signal generator is adjusted until the same
audio-frequency output is obtained with
standard test modulation. The output voltage of the signal generator is recorded and
compared with the signal-generator output
voltage required for the 20 db usable sensitivity tf'st input. The ratio of the output
voltages may be expressed in decibels and
gives the adjacent-channel selectivity for
a generator (lctuning of 10 kilocycles . . The
alternate-rltannel selectivity is found with
the genel'ator detuned 20 kilocycles.
This test is to be repeated in steps of
10 kilocycles up to 100 kilocycles off reso·
n~nce, or .80-db selectivity or 100,000lll1crovolt SIgnal-generator output, whichever is the smaller. This test is to be repeated with the-signal generator above and
below the tuned frequency of the tuner.
. . If the tuner. is equipped with a selectIVIty control, this test is to be repeated in
all positions of the selectivity control if a
step-type control is used. If a continuous
selectivity control is used, this test is to be
made for the condition of maximum and
minimum selec~vity.
The rated selectivity shall be the adjacent-channel selectivity at the standard
mean carrier frequency with the selectivity
control adjusted to give the highest degree
of selectivity.
7.05.05 Frequency Response
The frequency-response test shows the
manner in which the audio output of the
tuner del?ends on the modulating frequency.
It takes llltoaccount all the characteristics
of the tuner. The tuner is tuned to a signal
at th~ three standard carrier frequencies.
The SIgnal generator output is adjusted to
5000 microvolts, amplitude modulated with
standard test modulation. The tuner output
is measured with all tuner controls set to
the normal control settings. The audio output is observed while the modulation frequency is, v«ried continuously from ""30. to
15,000 cps. The results are to be compared
to the response at 400 cps and are to be
expressed in decibels.
This test is to be repeated f or all settings of the selectivity control if a step~ype control is used. If a continuously adJustable control is used this test is to be
repeated at the minimum and maximum
settings of this control.
If the results of the frequency-response
tests are plotted, semi-logarithmic paper
sha~ be used and a 20-db change on the
ordlllate shall correspond in length to 1
de.cade of frequency variation on the abSCIssa.
If the frequency response changes with
volume control setting, thiEi test shall be
~e.paa.ted at selected attenuation differing
~n steps of 10 db from the position of maxImum· output. . It. is not necessary to make
the frequency-response test or plot the observations below - 20 db or 10% of output
voltage, although further observations may
be desirable for special purposes.
It may be desirable to repeat the frequency-~esponse test!! at an input level corresponding to a signal sensitivity input for
30 db uS!tble sensitivity. Comparing this to
the preVIOUS tests may show the influence
of the automatic-gain-control circuits on
frequency response.
The rated frequency response shall be
measured at the ' standard mean carrier frequency and the- signal generator set to prod.u~e a 5000-microvolt output with the selectIVIty control of the tuner adjusted to give
the 10~est degree of ~electivity. The lowest
and highest modulatlllg frequencies where.
AUDIO
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•
JUNE, 1959
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ead
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CONTROLS: Selector, FM Tuning. AM Tuning. Separate Bass
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@
AUDIO
•
BOGEN-PRESTO CO.,
Dept. A69, P. O . Box 500, Paramus, N. J. A Division of the Siegler Corporation
51
JUNE, 1959
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the tuner ontput has decreased 3 db from
the 400 cps output are to be reported. If a
10-kc filter is used the bandwidth of this
filter is to be stated. The 10-kc filter bandwidth is defined as the difference of the two
frequencies near 10 kc where the audio output of the' tuner has been reduced 3 db
from the 400-cps output.
7.05.06 DiStortion
The test is intended to evaluate the
spurious audio-frequency harmonics which
appear in the audio output of the tuner
during normal operation. Care shall be
taken to avoid appreciable distortion occurring in any part of the signal generating
equipment or in the output measuring circuit. Distortion measuring equipment is required in the tuner output circuit and shall
not appreciably affect the output load condition. This equipment may measure each
frequency component individually or may
measure all frequency components collectively. A proper tuning of the tuner is important in making distortion tests. No one
complete set of conditions can be prescribed for this test because distortion depends on so many details of tuner design
and operating condition. Distortion is
caused by overloading and by many other
phenomena and is present under various
operating conditions, especially high degrees of modulation. The following series
of tests are intended to show the effect of
operating parameters on distortion.
(a) Variation of Output
The tuner is tuned to the standard
mean carrier frequeucy and a 5000
microvolt signal with standard test
modulation is applied. The distortion is noted as the output of the
tuner is varied by means of the
volume control.
(b) Variation of Modulation
At the standard mean carrier frequency with the above signal input
and a 400-cps modulating signal
the modulation is varied from 10%
to 95% of maximum and the distortion observed. The volume control is left in its maximum position.
(c) Variation of Input Signal
The distortion is recorded as the
signal input level at the standard
mean carrier frequency is modulated at 400 cps is varied. The test
is made at both 30% and 90%
modulation. The distortion should
be recorded as. the signal input is
varied over the entire range of input voltages (up to 100,000 micro-·
volts) in steps of 20 db starting
with an input corresponding to 30
db usable sensitivity. This test indicates distortion due to detector
and automatic-volume-control characteristics. It may be desirable to
repeat this test with_a modulation
frequency of 30 cps.
(d) Variation of Modulation
Frequency
To disclose the effect of the modulation frequency on distortion,
test in Paragraphs (a) and (b)
shall be repeated at several modulation frequencies throughout the
audio frequency range. The maximum modulation frequency at
which harmonic distortion can be
detected by this method is onehalf the maximum frequency
which can appear in the output.
In making distortion tests at the
higher frequency, special apparatus and special test methods (such
as simultaneous application of two
modulating frequencies) are re-
quired. Harmouic di6tortion measurements are useful and significant up to modulation frequencies
of approximately 1000 or 2000 cps.
At higher frequencies the selectivity characteristic of the tuner may
attenuate the higher distortion
products severely and may give
rise to considerable errors in measurement.
.
Measurement of distortion at the
higher modulation frequencies will
show up deficiencies such as caused
by inadequate bandwidth or phase
shift of the selective circuits of
the tuner or the detector circuit.
In this case, the distortion product
of most interest is the difference
tone obtained when the carrier is
modulated by two audio frequency
signals differing by less than 500
cps. For this test, a signal generator is modulated to identical modulation percentages by the two different audio frequency signals and
the arithmetic sum of both percentages is recorded as the modulation percentage. The total modulation percentage shall be 30% and
90%. The level of the difference
tone between the two frequencies
is measured in the audio output of
the tuner and its value is recorded
in decibels below 30% and 90%
modulation at 400 cps.
The rated harmonic distortion of the
tuner shall be the percentage of distortion
measured with the signal generator modulated 90% at 400 cps, the receiver tuned
to the standard mean carrier frequency,
and the signal generator set to a 5000microvolt output.
The rated intermodulation distortion
of the tuner shall be measured at the same
input level and signal frequency as above
and the total instantaneous maximum modulation percentage shall be 90% with the
signal generator modulated with two sig·
nals of identical ampli,.tude and frequencies
of 7000 and 7400 cyCles per seCO!l(l. The
400-cps output of the tuner shall be meas·
ured and shall be expressed in percent of
the output of the tuner obtained with 400
cps at 90% modulation.
It may be desirable to repeat these
tests at the other standard earrier frequencies and also at the different settings of the
selectivity control.
7.05.07 Spurious Response
With the tuner tuned in turn to each
of the test frequencies, the signal generator shall be continuously varied over a wide
frequency range to discover if the receiver
is simultaneously responsive at frequencies
other than the test frequency. These other
responsive frequencies are called "spurious·
response frequencies" and are more often
found in superheterodyne receiveds. This
spurious-response frequency is noted and
the spurious-response sensitivity test input
is measured as in the usable-sensitivity
test. The ratio of the generator output for
spurious-response measurements and the
generator output required for the usablesensitivity test for 20 db signal-to-noise
ratio may be computed and expressed in
decibels. This is called the spurious-response ratio. This test is properly classified
as a selectivity or interference test although its procedure is that of a sensitivity
test. Care should be taken that the harmonic output of the signal generator is
attenuated sufficiently so that it does not
affect the observation of the spurious reo
sponses of the tuner.
Two particular spurious responses are
not covered by test and will be treated
separately.
52
(a) Image Response
A superheterodyne tuner is generally responsive to two frequencies
whose difference from the local
oscillator frequency is equal to the
intermediate frequency. One of
these is the desired signal frequency and the other is the image
frequency. This is a special case of
a spurious-response frequency and
is tested as such. Its observed
characteristics are referred to tiS
the "image-sensitivity test input"
and "image ratio." The result shaH
be expressed in decibels and is to
be performed at a signal level cor·
responding to a usable sensitivity
of 20-db signal-to-noise ratio.
(b) Intermediate Frequency Response
Another special case of the spurious response in a superheterodyne
receiver is that due to the sensitivity to an intermediate-fre:}uency
signal input. The test procedure is
the same as for the other spurious
responses except that the input is
adjusted to the intermediate frequency. The observed characteristics are referred to as the "intermediate-frequency-response sensitivity" and the "intermediate·frequency-response ratio." The results
shall be expressed in decibels.
7.05.08 Hum and Noise
Hum and noise of the tuner are produced in two different sections within the
tuner. One of them is the audio-frequency
circuits following the volume or level eontrol. Hum and noise are measured as the
residual output of the tuner with the level
or volume control set to the condition of
minimum output. The results are expressed
in decibels below 1 volt and are not
weighted.
The other causes of hum and noise are
found in those sections of the tuner ahead
of the volume or level control. For this test
the total output of the tuner is measured
when the tuner is tuned to a signal of 5000
microvolts at the mean carrier frequency
and the generator is not modulated. The
results are expressed in decibels below the
output obtained with standard test modulation.
7.05.09 Frequency Drift
This test is intended to show the variatic:1ll of the tuned frequency of the reo
ceiver. The tests are normally performed
with the receiver tuned to the standard
mean carrier frequency. The variation of
frequency is observed with the aid of a
beat signal obtained between the signal
generator and another oscillator of constant frequency. The frequency of the sig·
nal generator is adjusted so that the reo
ceiver is correctly tuned. This beat fre·
quency may be measured and recorded. AI·
ternate methods of measurement are possible but the primary measurement shall be
a measurement of the change in frequency
of the signal generator.
The test shall cover the following
causes of frequency drift·-and the result,
shall describe the operating conditions:
(a) The frequency varies with time
during the warmup period of the
receiver. A curve of frequency
drift is plotted with time in minutes as abscissas on a logarithmic
scale and frequency drift in kilo·
cycles as ordinates on a linear
scale. The time is measured from
switching the tuner "on," with
observations started one minute
later. The warmup drift in kilocycles shall be stated as the maxi(Continued on page 71)
AUDIO
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JUNE, 1959
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AUDIO
•
JUNE, 1959
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EDWARD TATNALL CANBY *
1. THE ORGAN -SCHMALTZ
TO BAROQUE
AI Melgard (It tbe CbicagoStadium Or.
gan, Vol. 2.
Audio FidelityAFLP 1887
It doesn't matter how big a n organ is, the
leyel on your record is going to be the sa me.
To be s ure, Audio Fidel ity puts plenty or
level on its lliscs-but you 'll still need n
swimming pool 0 1' a gymnasium, plus nhollt
1000 watts- of- audi&, to make th is "theatre"
monster sound like itself.
With its 40,000 pipes, 883 stops, s ix manuals, etcetc_, this machine might do almost
anything for any organ ist, especially if he
had tweh'e hands and fi"e feet. For Al Melgard, here, it plays relath'ely gently, gen tly
like a hippopotamus at piny, let's say. The
strings are like string bea ns, the qnaverln~
song-pipes sing dizzily, the reedy stops brn~'
like Il erds of donkeys. A fine sound, all ill
all, and the extras a r e there, too, from
castanets on up.
1I1r. Melgard tends to a rather uelii.lerate
pace nnu a certain . cluJl).siness, perhaps h., :
cau se of that eilo rmou's ' eighl.seconds or -so
of re"erberatlon with whic'il 'he must contend.
(We are close-up and we don ' t hear it much.)
l.'his is no George Wright whirlwind. But,
for a staui Ulri , the place isn't bau. nor the
music.
Next t ime you hear thi s organ there'll be
another convention goin '! on - shndes of 11'DR,
(And d~ I remember this " er~' mon ster, then.
bellowing o,'er the crowds of delegates.)
The King of Organs. Bill Floyd . Wurlitzer
at the Paramount, New York.
Cook 1150 stereo
No hippopotamus here---this organ lIIoyes
as fast as lightning under Mr. Floyd's sophisticated fingers and toes. His style is.
relatively, qnite modern 'within _t he. theatre
orgilll tradition, the harmonies- thick anu fast
and fairly complex;-swin g style.
This is one of the old and famous Cool'
stereos, once heard on the old two-hand
stereo discs and on Cook tapes, if I am right.
I don't know what has happened to the n ew
Cook disc line si nce last fall when I got this
and several others. Not a word since. The
record is made via microfusion (powdered
vinyl) in transparent blue. It's good, but no
better than standard presslngs as fa r as I
can hear. Noise level is slightly higher than is
now normal for black.
Alas, the disc Is 'way off-center, my copy.
Funny-CoOk's old t wo-track stereo is dime
In a style that's l\.1ready a bit o,ut of dane in
sound-widespread, picked up fairl y fn.1' ·back
In the theatre, without· the smooth , close-up
edge that we are now uscd to in our stereo.
Purely a matter of taste; but - tastes change.
Leon Berry at the Giant Wurlitzer, Vol.
3.
Audio Fidelity AFLP 1844
This one I h ave in mono form and I've lost
th e cover-It was in somebody else's em·elope.
* 780 Greenwich St., New York 14, N. Y .
No matter-my message is brief, This Wurlitzer, not ideutified on the record label, is
obviously mounted in a large closet. (Mr,
Berr~"s basement, actually,) There's no apprc('iable li veness, anyhOW.
'l'bat mal,es (or an impression of intima cy
;lIld, at the same time, a wonderfu l clinical
lo01"see into the organ 's tonal machinery,
This player really pulls out his stops (touches
his little colored stop-tabs, to be more accurate) aud ~' ou ' ll h ear c~'mba ls , xylophone,
hells aua anything else yo u wish to mentiou.
.'\. good, close·up study of theatre orga.a tone
and the same goes, no doubt, for the other
\'olulllcs in the series, which presumably will
be endless so long as you kee p buying. Superhi-fl, needless to say,
Buxtehude: Complete O rgan Works, Vol.
1. Jorgen Ernst Hansen . Organ of Christianborg Chapel, Copenhagen .
Haydn Society HS 9054
The Haydn Society is back, after some
," ca rs of the stillness of dea th , and a new
flow of ~ntel'esting mu s ic has started up again
from this once-leading small LP outfi t. This.
-organ record may remind- you of, th-Ii pioneer
"Baroqu e" organ recordings from H aydn
Society by the Dane, Finn Vider~, made at
Sa r~ in Denmark in the early LP days. This
man is a pupil of Vider~ and a livel y, if somewhat metronomical plurel', confident, bra sb,
accurate, not very subtle in his expression
:lUt a lways impeccably correct In the execu·
tio n of the sty le.
Buxtehude neeas such a lively approachhe can use a certain boisterous feeling, speaking in figurative terms, of course. He was n
strong, bright, outgoing personality, full of
humor, a grand showman as well as a sensitive musician. The solemn, a ntiquarian approach of some organists towards this kind
of music is death for Buxtehmle. Better any
day an accurate, brilliant, outgoing organist
like this than a plodder, even tf be. is a bit
metronpmic,
The organ dates fro III 1826, wbich is ver~'
lnte for a " classic" organ, but its sounu is of
the right Buxtehude so rt, complete with
whistles, Hchiffs/' snarls, hoots and a gen~
emily steam-calliope tone quality, Real
Bal'oque--th e 1826 buildcr must ha\'e been
very old-fashioned in h is tastes. It's a big
instrument and does h ave a somewhat more
massil'e sound than the earlier classic instI'u men ts, as far as olle can tell from the r ecording, but there isn't any high-pressllre
~omantici sm to be found in it, That would
have come n bit later in the -nineteenth century, at least in DeUl!lark.
The King of Instr.uments, Vol. XIII~The
O rgan in the Mother Chu-;ch. 'Frede ~ ick
Jagel, tenor, Ruth Barrett Phelps, organWashington WAS XIII
ist.
What a roma ntic contrast! I took a look
at the l\Iother Church organ (Christian Science) a couple of summers ago when I was
in Boston, Impressive, if sligh tly gaudy. 'fh e
sound of it can be summed up in a wordreverent, Indeed, the whole a tmospbere of the
Mother Ch u rch itself is reverent, with polite
ladies \yniting for YOUI' "isit, to escort ~' ou
around aud give you a spiel in low voices
about its wonders, including the orgnn, A 1'ar
cry from the world of the jolly ruxtehuue--but one of his ' works, ' a Chaconne in E Minor
(also on the Haydn SOCiety di sc) som ehow
gets into this recital, eyen 8 Q, It is, of
course, transmogrified, the color and "erve
replaced by a subdued and respectable dignity,
Quite nice, but I'd neyer have recogn ized
Buxtehude if -I hadn ' t read the label!
This organ len us itself to the sort of
sentimental sacred music that began _wi·th
lIIendelssohn, a.nd Mr, .lagel sings several
a lmost tearful items from that composer, to
sweet, soft, lu sh organ background. Mendelssohn was enou gh , howeyer, and I had to stop
a.t the la.ter .lagel items, which were mOre
than I co uld take, But the Fantasie in A of
Cesar Franck was lovely on this organ ana
most musically played. too . .lust goes to sbow
,,'hat style CRn do.
Wa shington Reco rds ha s taken over the
Aeolian-Skinner liKing of Instruulents "series, of which this is the thirteenth.
Bach: Ot-gon- Music. (Toccatas and Fugues in C, D mi., F, Fantasia and Fugue
in G mi. ) Fernando Germani, organ of
St. laurens, Alkmaar.
Capitol·EMI G·7111
FOUl' of the biggest Bach organ pieces nre
played Oil this reco rd and tlIe splendia old
Dn ' eh organ in the cheese market town of
Alkmaar is a glorious instrument on which to
play t hem. (Deutsche Grammophon has a lso
l'pcorded the organ, with the blind organ ist
H elmut Walch a-see Archi-ye catalogue),
'i'his organ ist with the Italian name, about
whom I have no information. does a gooa
job on these big works, playing with sturdy
energy and su reness, a fairl y metronom ic
beat. The recorded soun d is good, but two
minor failings must be noted, (a) there are
some unfortunate tape "edits" to be heal'll,
where none should ' be audible, and (b) the
organ is out of tune In some stops. (It's in
tune for Deutsche Grammophon.) Don ' t know
w hat got into EM!.
The organ as now restored is almost ex·
actly as it was rebuilt in. 1725 . (using many
mnch olde r pipes)-the mns ic was composed
within a f e w years of this same date. Good
combina tion !
Mendelssohn: O rgan Sil na ta #4 in B
Flat. Wid or: Organ Symphony #6 in G
Minor. Alberf 'Schweitzer, organist.
Columbia ML 5290
Though Schwe itze r was lon g knowu as
lJoth a B:lCh specinlist and a Buch organist,
actually his musical t rainiug was at the ext reme opposite, in Paris of the late nin eteenth century wh ere the high-Roma ntic
school of F. ench organ music was at its
prime, fo llow ing Cesar Franck, In his recent
recordings Schweitzer has gone back to this
school-his last was of Cesar Franck-lind
his playing immedin tell' strikes a more authentic note. The Schweitzer Bach is now
rather fundamentally out of style (though
AUDJO. •
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JUNE, 1959
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55 ·
JUNE, 1959
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still timelessly noble In conception) but the.
schweitzer Mendelssohn and Widor are right
on the beam.
The organ here Isn't specUled but It is
decidedly not a "Baroque" or "Classic" instrument ! . QiIlte right. This is music In the
Romantic tradition, fora big, blurry, grandiose organ replete with swell boxes and
masses of nicked pipes, imitating a large
orchestra in Its impact If not In tone color.
Schweitzer's fast movements on this organ
are somewhat stltf-muscled and far from
fiuent and even with tape editing (we can
assume), there are slips of the finger and the
foot. But Schweitzer always did play that
way; he's been the horro.r of the academic
organist for a halt century! The slow movements show him at his best, a really noble
and expressive musician who can bring out
the most profound emotional levels In the
music where others merely play the surface,
impeccably. A grand old man, no doubt
about It.
tend to the more "authentic" playing style
since that Is his special field; how far, he
could convince Sir Adrian B.-and how far
Sir A. could convince' his profeSSional symphony players-Is a question. Anyhow, they
compromlse.d successfully and the. gettingtogether is generally harmonious throughout.
2. BIC STUFF
Tchaikowsky: Symphony #5. Boston
Symphony, Monteux.,
RCA Victor LSC 2239 stereo
startled at some of the streamlined speeding
here' combined with highly emotional playing
and lot~ of ru bato (slowings-down for etfect).
Nope, this 16n't the old fashioned, long-drawn
out Tchalkowsky one llttle bit. . Strictly mod·
ern, in a highly Romantic sort of way.
Tchaikowsky: Symphony #3 ("Polish").
Vienna State Opera Orch., Swarowsky.
Urania USD 1026 stereo
This is the third disc in a trilogy of the
early Tchalkowsky symph,mles (the First,
Second and Third, subtitled "Winter Dreams,"
"Little Russian" and "Polish") that to my
mind ranks collectively near the top In over'
all recorded value. Here's the oilier recent
Ah! Now here Is the kind of record that
brings me to full confidence in the tremendous value ot stereo recording-not to
mention hi-fi and, Indeed, recording itself.
one,Just terrific.
First, old Papa Monteux Is surely one of . Tchaikowsky: Symphony # 1 (''Winter
the greatest conductors of the last fifty years,
Dreams"). Vienna Philharmusica Symperhaps less flamboyant but a far wider, more
resourceful, more etfectlve conductor even
phony, Swarowsky
than the famed Toscanlnl. This is such a
Urania USD 1010 stereo
superb
performance,
down'
to
the
last
detail
The Organ Concertos of Handel, Vol. 2 and In the over-all sureness of shaping nt
I'm not clear as to what this "Philhar·
(Nos. 7-12, Op. 7, #1-#6.) E. Power every level, that I am sure it Is the soct musica" orchestra is-orchestras of Viennese
Biggs; London Philharmonic, Sir Adrian which at the end of Ii concert would bring habital:on seem to proliferate Into more and
cheers, yells, stamping of feet, bravos from
names as time goes on yet I suspect
Boult.
Columbia' W2S 604 (2) ster.e o any audience. It's not merely brilliant and fancier
that, most of the time, the same familiar
electrlc--much more than that, It has every
players are doing most of the work. In any
I missed t)le first volume of this interestIng three-volume set and so, too, I missed the bit of that sharp, clean, impeccable styllng case the State Opera Orchestra Is generally
that is a French specialty, without a trace of
take'n to be the Vienna PhillJarmonic In a
detailed descriptive booklet. that Columbia
over-tension, sloppiness, vulgarity (so easy in
second and independent corPorate existence;
thriftily oifers only In Volume 1. Thus I donit
Tchalkowsky), and yet every note at its most
the Phllharmuslca might combine a few of
have the immediate answers to several nice
pointed, for the total impact, right to the end.
these dual-title boys with members of the
questions that the music has raised In my
And
the
greatest
facet
of
all
this,
to
my
mind,
Vienna Pro Musica Orchestra, if such an
speculative mind. I can use my imagination
understanding
of
RoIs
Monteux's
superb
to good effect, though, and so can you.
outfit exists.
mantic rubato, that emotional unevenness of
You may herewith forget all that, and take
This, you see, is a typically Biggs-style
tempo that can make qf ruin a big piece like
my word that this, too, Is a top-rank stereo
project; for the organ itself is one that
this-that mU8t be pre)jent and yet Is horriof beautifully recorded, well-played Tchaikowl!andel actually , plaY1~ ",gpon-indeed, he deble If done without understanding and experisky, not too hysterical, yet full of busy,
SIgned It-a~ 1urB, remained virtually unPapa
Monteux
Iii!'
second
to
nobody
In
ence.
expressive life. These records are particularly
changed since Handel'S day, 200 years. But
this-not even the great Mengelberg, who
good in the orchestral details. Within the
old organs bring' problems, over and above
was surely the most profound master of this
large, golden lIveness, the Individual strands
the question of reliabllity inaction.
technique
to
llve
into
the
era
of
recorded
of the musical fabric are both clear and
First, this organ is' located at an out-ofperformance.
.
natural, a difficult combination to hit. The
town estate, the' Earl of Aylesford's in Great
You don't need to know a thing to be
strings are smooth and well blended, though
Packlngton. Yet here we have the London
thrilled by this Monteux Tchalkowsky; but
close; oboes, clarinets, percussion, are sharply
Philharmonic in all its majesty, playing-by
the more you know about the music, the
defined but never exaggerated. A real feat of
the sound of it-in a London-sized concert
more you'll be amazed.
stereo recording, I'd call it, and the technical
halr. Did the orchestra travel to the ' organ,
stereo
Is
a
pleasure
to
listen
Second,
RCA's
quality of the sound is as fine as you'll hea.r
en masse? And If so, is this fine,big llveness
to-so positive, natural, definite, so easily
the natural one at the organ's prlvate-estate
at this stage in the game.
and well balanced for the right musical etfect.
What's more, you'll enjoy the brash, game,
location, which seems surpr~sing, or is it by
I guessed this was a triple-track job without
fiavor of this youthful Tcha!kowsky, full of
chance a product of Columbia's fine, big New
looking;
it
has
the
clarity
of
middle,
the
even
his characteristic big melodies, his heady
York echo chambers? Could be either!
nearness all the way across, that is typical
orchestrations, fancy rhythms, but lighter,
Or-speculatlon continues in my mlndof well-done three-track stereo. It is so reless p(lrtentous than the late and more
is It possible that the orchestra stayed at
assuring, here, to be able to locate the first
familiar symphonies. Maybe this music Isn't
Its home base--played in a London hall or
violins
where
they
belong,
the
brass,
all
the
as "great" but to my mind it makes just as
studio-and the organ was spiritually transrest, without vagueness and yet without a
eifective listening. Try all three of these
ported thither via tapes, the two elements
trace of exaggeration either, every part of
recorded separately? Possible, though not
Uranlas.
the orchestra clearly In spatial balance with
probable. Mr. Biggs could have played his
the rest, the whole texture of sound beautiHaydn: Symphony #94 ("Surprise").
part llrst-maybe--and the orchestra could
fully clarified by the stereo separation. Just
have accompanied the tape playback. Not a
Oslo Philharmonic, Oivin Fieldstad.
wonderful.
very artistic way to ' do it, but such things
RCA Camden CAS 481 stereo
get done, these days often enough, and sucTchaikowsky: Symphony #5. Oslo Philcessfully.
This Is a bargain, too, but In ways unThen there's the matter of pitch. Do I
expected. Yes, it Is "low-prlced"-but since
harmonic, Odd Gruner-Hegge.
recall recently having read an account of this
the symphony Is spread out over two whole
RCA Camden CAS 489 stereo sides, whereas every other LP recording that
recording that spoke of the lower pitch that
prevailed In Handel's day and the strangeness
I know gets it onto a single side, the actual
This one Is a price bargain-for the symof hearing a Concerto In D minor come out in
cost of the music Is about the same as In
ph.o ny Is plenty long enough to fill two sides,
say, C-sharp? I dunno-but I checked this
standard lines.
even at the fairly rapid pace It takes on In
album, not having absolute pitch myself, and
For the hi-fi man, the bargain aspect comes
this version.
I find that It is precisely at modern pitch.
in the quality, both musical and technical.
A new recording, and I wonder whetbl'T
It's the same, anyhow, as the Cleveland
This stereo series Is new recording, of COUl'll'l,
RCA took it over from the Norwegians or
Symphony, the Vienna Philharmonic, etcetc.
not a reissue of "oldie" stnifas with many
sent out an RCA team complete with RCA
Now has the organ been tuned higher? Or
Camdens. The short length of play here is
half-Inch, three-track Ampexes? In any case,
was the tape playback speeded up? Did the 'the sound Is mostly excellent, for a good
an advantage In terms of wide, clear, unforced
London Philharmonic play on pitch-modern
cutting, with no trouble at all In tlJe
groove
stereo effect with sharp, clean details and a
pitch? It probably had to, for it Is tiimally
inner groove,s and an easy stylus travel
pleasing over-all llveness. I say "mostly"
throughout. Fine, big stereo sound, sharp and
impossible to tune the wind Instruments down
because I get the impression that the very
far enough, even though the strings can alwell separated In the details.
.
loudest portions of this very loud symphony
ways be let out a bit. Anyhow, the record Is
The Oslo orchestra, In spite of RCA's imare a bit ovei-loaded, here and there, with a
up to modern pitch and the organ matches
plied downgrading via the Camden label is
slight hangover feel to the drum-punches.
the orchestra, however it was done.'
a first rate band and Its playing Is positive,
(It's a faint shadow of the etfect we used to
Answers to these questions are easily destrong, expressive. This Is one of the better
get In the old broadcasting days via seYere
termined, but I find It more fun to guess. (Go
recorded "Surprise" performances. It favol'll
llmlter action. The big drums, Instead of going
get Volume 1 and you can find out for yourn big, symphonic etfect, rather than the
BOOM, sort of go BOO-WOOM, if you see
self.)
small-orchestra authenticity of many recent
what I mean.) Slight, at worst, and I suspect
As to the playing, ·It Is pleasing, musical,
versions, but the playing Is lively, clean and
that most of it Is Tchaikowsky's fault for
and more or less In style. I say that because,
thoroughly musical.
writing music that can be whomped up to
I must confess, there are for my ear a good
the extreme Intensity of this performance.
Beethoven: Violin Concelto. Heifetz; Bosmany hints. of the old-fashioned, "non-authenDon't think this Oslo team Is a mere hired
tic" Handel In Mr. Boult's London Philharoutfit turning out potboilers on order! The
ton Symphony, Munch.
monic playing. Mr. Biggs would, of course,
performance reeks of personality; it is very
RCA Victor LSC 1992 stereo
much an "interpretation" and In a way,
1 Later---'I hear the pipes were actually
The stereo disc reissues are quietly buildrather a self-conscious one. It demands your
sawed off -to tune the organ higher-then
Ing up; this recording came out on stereo
attention In no uncertain terms and if you
tape (at the fabulous price of $19, If I
are an old Tchalkowsky fan you may be
patched back on again for posterity r
AUDIO
56
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•
JUNE, 1959
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57
JUNE, 1959
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remember rightly) back in early 1957, and
probably was recorded early in 1956. Here It
is on stereo disc for one tbird as much ns
its earlier cost on tape, which is enough to
recommend It.
The recording was dual-track, has the
usual big, convincing RCA sound (not as big
as the tapes made in Chicago at the same
time, with Reiner), the usual close-up RCA
placement of the soloist, squarely in the
middle, and the slight indefiniteness, so to
-speak, in the central area of the orchestra.
the very slight emphasis on the side areas
and on the wall-bounce from the auditorium,
that characterize the older two-track technique, Newer, three-track RCA stereo in til e
sam e hall has a more even spread, a somewhnt closer effect for the individual orchestral
sounds, a sharper sense of deta il, especially
from the center of the orchestra.
. A funny performa nce, this, and not exactl.v
, ·tll{! -all-tim{! .cla.ssie that you might think,
reading the cover notes. For one thing, the
tempo is so fast that old-timers will be
rea lly startled. The familiar Beethoven leisure.
so spaciously strung out in most earlier perform a nces of this work, is just not apparen t
h ere; thin e:s moye along in a rapid, busi\les' like way, beginning with the a lmost indecen thaste of the famous solo drum t a ps that oppn
fh e concerto, going straight on to the h11rried-up holds in the last movement- those'
pauses which ordinarily are practically deae!
stops, h ere nr e mere hasty acknowledgements.
Could this be a late reflection of Toscanilli ?
I don ' t think so, for Toscanini was never cool
and business-like in his high-speed -'Beethoven !
, My guess is that Mun,c h is the speed man ;
it is his somewhat metron'o mie beat -that l,eeps
things going here and chills a good den l of
the musical ardor in the process. Heifetz, a
good trouper, adjusts himself to t he fast e r
speed with a fine flair and with plenty of
top fiddling, only an occasional absent-minded
slur, from too much familiarity with the
mnsic.
Only at the climactic return of the opening passage of the first movement did I fef!1
that this performance really blazed outthat was good, that part. But the long, slow.
ornamental second movement is a metronomic
fiddle exercise, unimngina tively played, casting no Beethoven spell at all. Maybe Heifetz
himself was bored, in his highly competent
way.
Orff: Carmina Burana. Houston ;5)j:mphony, Houston Chorale, Stokowski. ,Capitol SPAR 8470 stereo
a very stimulating record, any
at it.
WilY
you look
3. TITILLATIONS
The Immo rtal Sir Harry Lauder.
RCA Camden CAL 479
This is astonishing! I h1d no idea that
such excellent sound quality might lurk in the
masters for those endless, scratchy old Lauder
records that sold everywhere and were played
to death in droves when I was a very small
kid.
I remember Sir H a rry-on records-most
vividly. We still have a pile of his discs
somewhere In a barn and a few of them still
play, more or less. One of my father's distinguished f riends, a college president for a
quarte r ceu tury, used to break into Lauder
(sligh tly on r of tune) whenever there was an
ouWoor picn ic or a -fireside get-together where
we WQuld lis ten to him. Surely, anybody over
40 mu s t remember that familiar ha-ha-haa
with t he u pwa id in flection, the chuckles that
couldn 't he suppressed, the laugh that broke
up eve ry so ng in the middle-and the famous
story "asi des" th:H interrupted confidentially
in the midst of the music, while the band
respectfully waited fOI: the chorus. It was
nicely calculated 'hnd wonderful showmanship right down to the kilt and the pseudoS ~otch ,accent that managed always to be
intelligible, eYen to the Amurricans. He was
good, LQ.nder.
Anrhow, h e re's Sir Harry back again, loud,
clear, h earty and darned near hi-fl. Amazing.
There's .1iardly a trace of ,background noise ;
the bass is big (oom-pah style ), the brass is
loud 'Rnll melod io ns and the voice itself is
almost ' distortionless, a big, rich tenor with
enough sibilan t S sounds to make every word
intellig ible. No faint echo of the dim, distant
past here! Sir Harry practically walks right
illtO yonr rOOIll. And the original records were
probably a ll of them acoustical, at that. A
fine reissue.
Come Fill Your Glass With Us. Irish
Songs of Drinking and Blackg~ar.ding.
Patrick, Tom, liam Clancy; " Tommy"
Mackem, Jack Keenan, with instrs.
Tradition TLP 1032
The Irish! These fellows (with one exception and he just plays banjo and guitar) are
real I rlsh and the songs they sing and play
here are the easy-going drinking and goodtime songs they knew as kids-which wasn't
so very long ago. What an excellent record!
un-a ssuming, -minus airs an-d graces, yet sung
with gusto alH! friendliness and , plenty ..of
style, it'll melt anybody's heart, even a
simon-pure folklorist. For my money, they
put the Weavers to shame.
The three Clancys, bass, bllrltonish and
tenorish, are variously involved In acting-,
folksong collecting, producing, and what-not
(they run Tradition records more or less, I
gather) but there's time left for this sort of
thing, and I'm all for it. All of them, and
Irish Tommy I\fakem, have excellent natural
voices, and each has his solo here, with guitarbanjo back-ground and a lively accompaniment from tin whistle and harmonlca-whicll
they play with musical finesse of a high order~
when they aren't singing. Hi-fl-of course.
The enormously popular Orff work is r ecorded here in the performance that first
brought it to U.S. attention, with Stokowsld's
flamboyant ministrll tions, several years back.
The music is plenty striking on its o,,,n;
Stol<owski makes it really hum.
Orff Is a strange composer . He's a leading
German und a famous and influential teacher
whose me thods have affected all sorts of
composers of mllDy.,-tVlIation . His music, for
most of us, Is the antithesis of the German
-It's exciting, dramatic, minus all the tradition nl German virtues of structure, counterpoint, large-scale architecture-and turgidity!
Orff is nIl color, nIl display; his effects are
tran sparen t as air and as sharp as ultraviolet. And as for structure, his music is just
a long ch n in of en chanting, striking new ideas,
each one made dramatic mainly by highpowered repetition. Germany practically inOld Music Box Waltz Melodies.
vented musical key-modulation-but Or1l' stays
Bornand RCB-4 (mono)
put, in one key, until you are fairly - hypnotized. It's both subtle music and obvious
, Bornand sends me this, reminding me t!la!
music--a plel!~a!!t - ' co~b ination, decidedly.
' I , onc~ ,enthused over the first Bornan!!_-m llsic
Orff's inspira tion, as -som'e' li st ene rs will
,box .recQl'ding as a remarkable novelty! -It
disCllver, comes first of an from·-t he music of ' surely was', a nd the proof is merely that mnsic·
Medieval Europe. (His' texts ,tend to run to . - b'ox records are all over the place now. This
Latin, and he likes the ea'r ly Medieval rhymed '"" is , a Tenth · Anniversary disc but, since the
sort.) But the Orff illea ~of "~:[ e dieval " is not
label reserves all rights as of October, 1955,
exactly the usual one-his concept is wild,
I'm not exactly clear as to the present stretch
racey, dynamic, earthly, full of strong
of time. back to the First-was It 1945, on 781
rh ythms, lusty color, folksy tunes. Pretty
Guess It must haye been .
strong stuff and a lot better than some of
A batch of hi-fi waltz tunes here, played on
the more musicological reconstruc tions of
a half dozen music box monsters, the kind
actual older music that we now hear.
with low, low bass as well as tinkling highs.
Above all, Orff has a fabulous way with
The company has other discs, graded as to
voices- chorus. solo, and speaking. Singe rs
size from single 78's (for those of us who
just can't sing Orff without getting highly
haven't yet discovered the LP) through 45'~,
excited , and this excitement is immediately
ten-inch , 12-inch 33's-no stereo as yet and
transferred to every listener .. All this Stokowjust as well. (BornanrL Music BO(J) 00., 139
skf"knows full well. ,A:iid so ,y ou'H' -fi nd this
4th Ave., P-e!Jw'm, N. Y . )
58
AUDIO
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•
JUNE, 1959
t;,......
De Banfield: Lord Byron's Love Letter.
Libretto by Tennessee W il liams. Vornay,
Ribla, Carlin, Carruba, Academ y Symphony Orch. of Rome, Rescigno.
RCA Victor LM 2258
.. -~--::.•~. .
'TRIMENSION:A~'
. ;';;it
-TMS-2
Components: C-12HC dual voice
coil ~woofer, two "S" mid-range speakers. two wide-angle
tweeters, two networks with "presence" and " brilliance" controls.
Dime-nsio..... : 30" wide. 26" high, 12 %" deep.
User net: mahogany - $268, blond or walnut - $26 3.00.
Ugh. This is one of those dreadful ("0 I
hear them) folksy American operas 6UIl~ in
low-brow English by vast, 'bosomy, -iItaliim .'
sty le sopranos anil bellowing Caruso tell or".
where one keeps feeling, rather violently, t lt a t
if on ly they'd all stop yelling we might he
able to figure out what they're trying to suy.
The music is utterly conventional, withou t
style, grotesquel y unsuited to any sort of
effort by the terse and stageworthy Tennessee
Will iams, who ought to have kept him self out
of this dism al affair.
Sorry, but if RCA is going to send out
recorils of this worth, it's up to us to review
them as we hear 'em! (The story is .ai>meth ing
about a couple of old N'Yorleans gals who
have a love letter from Lord Byron that the
tOUl·,sts come in to see. Faded Suthunn aristocracy and all that.)
The New York Taxi Driver. Recorded by
Tony Schwartz. Narr. by Dwight Weist.
Columbia ML 5309
Tony Schwartz is a full-time New Yorker
with a positive genius for candill recording.
He ne,'er goes anywhere without a small
portable tape recorder ' (currently' a Swiss
model) and he n ev€r, if I am right, plays
tricks on his subjgct -, they a l ways know they
a re being recorded.
It's a.JJ the more amazing, then, tha t Tony
gets such utterly easy, natural, fluent COIllment from th e people of New York-including
taxi ilrivers. The Schwartz recordings nre
heard week in and w eek out on radio and
ha ve been collected in numerous r ecords for
Folkways; it looks as though Schwartz was
about to graduate into big-company work. But
there are a few problems.
Come to thin], of it, maybe it's just as well
that the occasional narrator here, a standardvoiced big-company announcer, has such
idiotic stufi' to read IllUI does it in such a
de-humanized, commercial-sounding manner.
It makes the taxi men sound a ll ,t he better.
Don't think they aren't human! Fortunately,
the narrator only breaks in once in a blue
moon, and mainly fo r vocal contrast and a
moment of peace and quiet after the noises of
New York's streets.
As for the boys, they aren't always too
easy to _understand, what with Bronx accents,
auto horns, meters, transmissions, and whatnot . . But under the circumstances they ilo
br11lia ntly and you'll get the gist of their
amaZing tulk e,'en thf( , fi~st' time over. Of
course, tuxi drivers are famous for their conversation-even more famous than barbers.
Of course, they have to 'yell to be heard. But
to get the "feel" of a way of life, so graphically p resented, onto a set of tape recordings,
is something to marvel at. Nobody but Tony
woule! even think of it, let a lone collect
countless hours and hours of taxi stufi' as a
base for- these excerpts.
The montage a t the beginning, I suggest,
is the poorest part of the whole and the
least understandable what with a constant
interchange of voices, each man ove rlapping
the next after a few sentences (via trick
editin g ). Don' t be discouraged. The next
sections take you thr ough single sub jectsIt's amazing what quantities of material
Schwa rtz got on a given subject like women,
hOld-u ps, home life (particula.rly poignant) ,
art, psYchiatr:y, .,p-ollcemen;- New York 'geogra·phy. And t hen there !Ire.. .sev~e_r.!tl ~ quite long
stories whel'e the 1l'fivers' -- p'ei'sonIl.Jities come
through almost lumin ously.
A un iqu e recoril-for New Yorkers, who'll
feel utterly at home, and for .out-of-tow·ners,
who will probably be .ntterly bewililered.
The He;d Rides Again . . • in Stereo.
Woody Herman .
Everest SOBR 1003 stereo
This is a composite recreation of the sound
of the famous "Herds" of the mid-forties
(Continued on page 67)
AUDIO
•
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JUNE.: 1959
59
www.americanradiohistory.com
AmericanRadioHistory.Com
s ide, where a more con\'entional lineup swings
into action and speaks the language taught
by Basie. Guitarist E\'erett Barksdale is
added, and Hall retUl'ns to piano behind
Buck Clayton, Rudy Rutherford , and Buddy
Tate. Not to forget t he leader's stop time
chorus on his own Corne A nd Get It.
Budd Johnson: Blues A La Mode
Felsted 5JA2007
CHARLES A. ROBERTSON*
STEREOPHON Ie
Ahmed Abdul-Malik: Jazz Sahara
Riverside RLP 1121
Mohammed EI-Bakkar: The Magic Carpet
Audio Fidelity AF5D5895
Jazz embraced 0 rien tal effects about the
time a Chinese restaurant first hired a dance
band, employing them with more 01' less authenticity and subtlety ever since. Largely
dependent upon transitory fashions in temple
blocks, tom-toms, and gongs, the imprints left
are sometimes dim. But when comb:ned with
compositions the caliber of Ellington's Camvan, they blaze a continuous trail to the more
serious approach now being made by musicians
on both coasts. It may lead across the Pacific,
on a course followed by Chico Hamilton, or
to the Middle East, the direction favored by
Dizzy Gillespie and others living close to the
Atlantic seaboard. Much of their progress is
limited to the grafting of new tonal colors
and rhythmic I'levices to " 'estern forms, with
Yusef Lateef being the most venturesome to
date.
Ahmed Abdul-Malik is convinced a clo~er
union would be realized by working from the
more flexible patterns and greater melodic
improvisation possible in this chord-free
music. In four compositions created for his
album, he makes the first tentative steps
toward what 'he believes can be a vast new
area of advancement for jazz. Born in Brooklyn of Sudanese descent, he is peculiarly
fitted to contrive such a blend, h aving played
at Greek, Syrian and Gypsy weddings as a
youth. Most recently bassist with Thelonious
Monk, he gained wide jazz experience under
Art Blakey, Coleman Hawkins, and Randy
We,ston. Before forming his own Eastern
group, he increased his knowledge of tlle subject by working for Djmal AsIan and Mohammed El-Bakkar. His ambition is to obtain
a fellowship or grant and visit North Africa
for further studies.
In addition to providing a bass lipe in support of Johnny Griffin, whose improvising on
tenor sax supplies much of the jazz interest,
he is able to solo on the oud. He also uses this
lute-like instrument in ensemble passages with
Naim Karacand, violin, and Jack Ghanaim,
who plays the 72-stringed kOl1J,Oon. Al Ha,rewood adds a jazz drum setup to tambourine
and da.·abek,a, a metal vase with skin stretched
across the top. Griffin sticks close to the blues,
but seems more at ease than in many of his
previous efforts. Enjoying considerable f"eedom, he manages the veteran's trick of IIPpearing to play himself into a corner and out
again.
In making cpmparisons, it might be presumed that the jollity ' and popular mood of
Mohammed EI-Bakkar's latest LP, the fourth
in a series, would serve to prepare unaccustomed ears for Ahmed's considered endeavors. The exact opposite is apparently the
case, however, as Ahmed's primary purpose
is to provide an introduction to the enormous
potential of the music. He concentrates on
those aspects best suited to jazz, using them
with skill and restraint so they may be
* 732 The Parkway, Mamaroneck, N. Y.
readily understood. After becoming acquainted
with his theories, it ,is easier to delve beneath such surface manifestations as ImBakkar's impassioned vocals and the bon'owing of cha cha rhythm for one number. Both
albums afford an unusual listening experience, espec;ally in stereo, and are excellently
recorded.
Dukes Of Dixieland: Up The Mississippi
Audio Fidelity AF5D5892
If they ever heard it disputed that jazz
came up the Mississippi, at least the Dukes
of Dixieland harbor iIlO doubts about their
own origins. And they have yet to desert their
New Orleans heritage for an album of show
tunes or popular trivia, Theil' ouly gimmick
is good sound and it is paying off at a healthy
rate. Since the release of their last LP, they
enjoyed the opportunity of proving to. New
Yorkers that what comes from the loudspeakers is really true. The clubowner who
met their weekly $3,000 fee, a sum previously unheard of for Dixieland in Manhattan, did a record business and booked a
return engagement, which was also "ery successful. Needless to say, none of their salary
will be in bricks from Haverstraw, N. Y.,
another reputed birthplace, although they
might give up a few nights of work to be
able to hear the old 101st Ranch band which
came North shortly after World War I. The
circus traveled by rail and could have pitched
its tents next to that legendary brickyard.
The A8suntos mal{e the trip in leisurely
stages, via such landmarks as Riverside Blues,
Old Man Rive,', and Down By The Ri,vel'sidc.
A rigid test of your equipment occurs during
the trombone and tuba duet on D eal' Old
Southland. When other companies provide
a more difficult hurdle in runout grooves,
you may question the wisdom of purchasing
a cartridge able to negotiate these passages
at 2 grams. Some still persist in cutting an
obstacle which sertds a light pickup bacl{ for
an encore on the last chorus. '''hat will convince them that tracking under 2 grams is
no longer a novelty? Perhaps the Dukes playing a dozen tunes in stereo 'on their ninth
album will help you forget about bricks and
runout grooves.
Dicky Wells: Bones For The King
,
Felsted SJA2006
A blues written by Dicky Wells as a tribute
to the late Tommy Dorsey explains the album
title, and it introduces in turn fellow trombonists who are masters of the idiom. George
lIiatthews, Benny lIiorton, Vic Dickenson, and
'VeIls form a novel quartet, made unique by
the addition of Skip Hall, organ, lIlajor
Holley, bass, and drummer Jo Jones. It
allows for brisk exchanges that are quite
arresting iJ;1 stereo, and no other medium
could convey as well the humorous repartee
during Sweet Daddy Spo-de-o. The difficulty
arises from placing the oogan too much in
one channel. This is a feat which even London
is unable to perform successfully at present.
So you can try your luck at removing it
from its confines and juggling it into reasonable balance with the other channel, or play
safe with the monophon ic version,
.
There is 110 "uch , confl ict on the second
The last but not the least of the dividends
from Stanley Dance's visit to t his country
places Budd Johnson's name on a n LP as
leader for the first time. If the journey se rved
no other purpose, the effort would be wortb
while. In some ways it is the most attracti\'e
and unpretentious of the lot. Dance evidently
asked the leaders to bring originals and play
as they liked. Six of his OW11 themes , ha lf
of them blues, comprise Johnson's reply,
wrapped in his extremely mellow tenor-sax
work.
His quintet companion is Charlie Shavers,
who celebrates a release from trumpet di splay pieces by the most relaxed playing he
has done in some time. Trombonist Vic Dickenson and Al Sears, baritone sax, add their
voices in the septet. Bert Keyes' organ is
well handled in stereo, as is pianist Ray
Bryant's plunging left hand and Joe Benjamin's bass. Nothing momentou s bappens,
unless you so rate a drum solo from Jo Jones,
but that apparently was not the intenti on.
Hank Jones: Porgy And Bess
Capitol 5T1175
Miles Davis: Porgy And Bess
Columbia C58085
Mundell Lowe: Porgy And Bess
Camden CA5490
Some day in the future Gershwin's folk
opera score will enter public domain, but it
is hard to believe a larger flood of LP's will
follow the event than that attendant on the
film vers ion. The music is t reated to varying
degrees of modernity in the three up for
notice, with Hanl, Jones being generally most
interesting and cohesive. Al Cohn sketches
unusual settings for the quartet, allowing
brilliant iuterplay between t he pianist and a
supporting caRt of Kenny Burrell, guitar,
Milt Hinton , bass, and drummer E lvin Jones
in a number of percuss ive rol es. Two extracts not always cited are] Co,n' t Sit Dow " ,
and 1 Ain't Got No Shame. 'l'he stereo sound
is superb and will fit any living room.
Miles Davis, again collaborating w ith arranger Gil Evans, makes each interpretation
a little gem. They are required reading for
students of the modern school. In the absence of competing soloists, the emphasiS on
his horns, both trumpet and f1ugelhorn, may
be a Ii ttle wearing to others. It leads to a
sameness not alleviated by a balance favoring
Davis ol'er the other eighteen orchestra members. Try it in easy stages-'t will be well
worth your time, particularly for Gone,
Blizzard SO'110 and He,'c Collte (Ie Honey Mall.
Mundell Lowe leads a septet, billed as All
Stars, in low-priced stereo. But the only
point where economy entet·s into the production is the limiting of a second session of
thl'ee numbers to a trio. With players the
stature of Ben Webster, Art Farmer, land
Tony Scott in the studio, Lowe could -be a
bit more retiring. Titles not listed in the
two other albums are Redheaded Woman, and
It Takes A Long Pu!! To Get ThlJ1·e.
Bob Prince: Charleston 1970
Warner Bros. W51276
Red Nichols: At Marineland
Capitol 5T1163
Diehards of Dixieland persuasion should
be delighted with these two items. The fil'st
adds proof to their contention that good
Dixieland requires a special talent and many
young modernists lack it or never have
bothered to de'l'elop it. Bob Prince's idea is
to contrast pllsRages arranged in modern
style with choruses resurrected from 'the '20's.
He pulls off many surprises along the way, and
the tentette manages to convey what is written with considerable aplomb. But trumpeter
Donald Byrd is quite lost in the ad-lib portions, where only Milt Hinton, bass, and
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Don Butterfield, tuba', seem to know what
is go ing Oil. Of the four new titles, one turns
out to be Then I'll Be Happy. The moral is
not to attempt a spoof until certain it will
turn out better than the original. It takes
practice to be as corny as Pee Wee Hunt.
A live performance finds Red Nichols having
a wonderful time in the Porpoise Room at
Marineland, a Pacific resort more noted for
television's "Sea Hunt" than jazz, The Five
Pennies are unaugmented in this outing anrl
revive Ent,·y of the Gladiators, Cal'ol.na in
the Morning, and Lonesome Lovesick, The
cornetist is up to his old trick of following
a med iocre chorus by one as good as they
come. If he only coulrl be as ' cQnsistent as
his clarinetist, Bill Wood, 01' trombonist Pete
Beilmann, the Nichols' story might be different. His splendid tone is benefited by the
recording, and Joe Rushton, playing bass
saxophone, sounds as big as life in stereo.
Jack
Teaga ~den:
Shades Of Night
Capitol 5T1143
A woodwind choir is selected to su rround
the b' g, rounded tone of Jacl< Teagarden's
trombone in stereo, as he creates a dreamy
mood, The tempos are geared to solo meandering, with ample time for considered thoughts
on Cab:"
the Sky, Autu"... Leaves, and
Alone Together. Sid Feller sketches the back'grounds in lightly and they can 'be conveniently disregarded or not, depending upon
your tolerance for minor intrusions, Someday Jess Stacy and Teagarden may be reunited on a s;milar date, but a visit is paid
to such old friends as Diane, Jm,k Man, and
,n
St,'eet of Tears.
Yma Sumac: Fuego del Ande
Capitol 5T1169
Jo Basile: Argentine Tangos
Audio Fidelity AFLP1869
The pride of the Incas, Yma Sumac, brings
her fou r-octa ve range to stereo in a dozen
authentic folk songs of South America. Only
one, Vi," g ins of the S"", is sung without
lyrics in her exotic vocalese, a greater em-
phasis being " placed on the stories told in
Enchantecl La/ce, One-Eyed Rooster, and My
Pigeon, As might be expected, the medium
makes her vocal projection appear more stunning than ever, a lthough it is used less for
efl'ect thnn on other occasions, Tbe arrangements are by Moises Vivanco, who leads the
orchestra and manages to keep four electric
guitars and assorted percussion nnder control. A lUong the several rhythms is the
huayno, dating from 1000 n. C, and sounding
l'elUnrl~ab !y
lil;:e boogie woogie, a8 well as n
tnng0.
J 0 Das:le offers an alternate I'ead ing of
th:s last tempo, one adapted to the Parisian
tango parlol's where its 20th-century rev;"al
began, Centered among strings, his accordion
puts more bite than usnal into such danceable
items as A Media LIIZ, Jalousie, and EI
especially in stereo, is iIlust-rative of tbe pains
taken by .'the engineers. The program is light
but varied, indulging in such caprices as
Londondel~'y Ai,/"
Mexican Dance, Sugar Blues,
and Bartl,slca Pou.' a. (See Canby's comments,
page 54. )
Don Baker's instrument, the Robert 1I10rton
organ house<,] in the Lorin Whitney studios
at Glendale, California, is hardly as mammoth, boasting 2,000 ,pipes as compared to
a total of 40,000. It proves to be capaciou"
enough, however, for Richard Rodgers'
Sla'llghter on Tcnth Avenne, with its full-bass
pal'll phrase of Three Blind M ·i ce. The remainder of h :s repertoire is equally as challenging, and includes Alfred Newman's St.·eet
Scene, Park A venne Fantasy, and AI anhattan
Se,·enade. Both albums offer contrasting
values, and are brilliantly achieved in stereo,
Choclo,
MONOPHONIC
The Caballeros: Viva!
Hifirecord R816
Since the success of "T Town," their first
a lbum from across the border, The Caballeros
have moved on to the Desert Inn in Las
Vegas. Their forte continues to be Mexican
folk music and ballads, excellently played in
arrangements by Ruben Guevera, guitarist
and leader of the quartet. On one side are
guitar and the full, rich sound of marimbas,
baianced on the other by piano and accordion.
Percussions are heard in the middle and closemiking adjusts the stereo spread to the size
of a comfortable living room. The "ame effect,
without as much depth, is to be found on the
fine monophonic ,·e rsion.
AI Melgard: Chicago Stadium Organ,
Vol. 2
Audio Fidelity AF5D5887
Don Baker: S::>phisticated Pipes
Capitol 5T1171
Resumj.ng his concel't at the Chicago Stadilllll organ, Al Meigard discioses a second
quota of splenderous effects and a sweeping
ins'ght into its tremendous power. None of
the reverbel'lltion time is clipped off the ending of ,wy of a dozen numbers, and its depth,
Negro Folk Songs And Tunes
Folkways FG3S26
Josh White: Chain Gang Songs, Spirituals,
and Blues
Elektra 158
Elizabeth Cotton, a 59-year-old house·
keeper for the Seeger family, harks back to
the tunes and country rhythms of a chilrl·
hood spent in the vicinity of Chapel Hill,
North Carolina. Encouraged by her employers.
she remembers the spirit and context of most,
although the words of some still escape h'"''
Bnt not those to Fl'elght T 'r ain, a song she
calls her own, having passed It on to Peggy
Seegar, whence it went to Nancy 'Vhiskey anrl
the hit parade. Much of the interest lies ill
her guitar and banjo picking, however, and
Mike Seeger describes her methods in the
notes. The recording balance also favors the
in"truments o,'e l' her s weet but faint voice.
Rtllc1ents of both can learn a great deal from
Wilson Rag, and- her Vastopol and Spanish
Flang-dang tunings. For the blues enthusiast
there are Goi"g Dow" the Road, and I Don' t
Love Nobocly,
Josh '''hite, the man who first made such
material palatable to many, claims his just
DIMENSIONS:
, (8" system without base):
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13K/' deep.
STYLES AVAILABLE:
Three matching decors:
contemporary,
traditional, provincial.
FINISHES AVAILABLE:
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•
JUNE, 1959
due on the liner of his collection, stat ing,
"I've t ried to make the songs clear ; a nd I
feel if I and some other hadn 't done that
and helped people nnderstand what the stor ies
say, we wonl dn 't h ave as much interest in
fol k music as we do now. Another t hing I
have tried to show is t hat folk songs are
conversations. You don't have to shou t. Sn re
they did in t he open in the Sou t h ; but now
you can get into the int imacy of what t his
music says. It ough t to be as if I were just
talk ing to you."
The last remark is a .fa ir esti mate of both
his style and the arrangements he provides
for the voices of h is four male. accompan ists.
He reassembles many chain gang songs from
memory, capturing the smoldering f u ry and
tension of Cryi110 W ho ! C"yino You, T"ou ble,
and GOinO Home, Boys. His daugh ter, Beverly,
j oins in on a l ovely Ma'r y Had a Baby, before
entering into the ch eerful abandon of Eve,'Y
T'i1lle I Feel t h e Sp irit.
George Lewis Of New Orleans
Riverside RLP12-283
Ch ris Barber: Petite Fleur
LLP100l
Hudi Blesh , in hi s book "Shi n ing Trumpets,"
ch ronicles the revival of ea" ly New Orleans
jazz and his visit to t he city to record George
Lewis in 1946. An essential study, it is recommended as a supplement to th is reissue of
items fi rst released on his Circle labe\. It
explains why the sound su ffers from the use
of portable equipment, a lt hough t he remastering improves on the originals. Six marching
numbers by the Original Zenith B rass Band
are still unsu rpassed as representations of
the real thing, and t here is no substitu te
today fo r t he drumming of Baby Dodds. Both
he and Lew is also are in t he grou p whic]l
accompa nies Sister Berenice Phill ips, an
au thentic s inger of older J ubilee hYlll ns, a nd
Harold L ewis on t he second side.
A new edition of Blesh 's volume would requi re a section on the traditional ist movement in England, w here t he response to Lewis
con tinues to be great. It culm inated a decade
later in t he Ch"is nn.,'ber ba nd, wh ose clarinetist, Monty Sunshine" bases his limpid s t yle
directly on Lewis. The popu lar appeal of the
t itle t une brought the band and t his 1956
recording to t his cOllnt ry in t he Spring. Sunshi ne seems well on the way to adding Lewis'
creative strength t o h is liquid tone. On WUd
Cat Blues, h is banjoist is Lonnie Donegan,
a nother wh o collected t he hit parade geldt not
likely to be paid I,ewis in his lifet ime. The
liner .notes cleverly skirt a ny ment ion of h is
name, but t he sou nd has the resonance of a
large hall.
few still capable of using it with dynamic
effect. Always melodic. he a l ~o has a taste
fo r the neglected ball ad, inclu di ng a n apt Hnd
sea sonHI Spring Will Be A. L ittle Late Th is
Year.
Besides ripping into pop t unes with chamcter istic vigor, Waller sh ows what a left hand
on ce m ~ant in solos on Ge01'g:a On My JlIi,nd,
a nd Carolina Shout . AI Casey, Gene Sedric,
Herma n Autrey, and fla rry Dial are number ed
among h i s compn n iolls fi n d t h e sou nd is lli('el y
refu rbished.
Red Garland: All Kinds Of Weath e r
Prestige Z148
Fats Waller: One Never Knows, Do One?
RCA Victor LPM 1503
" 'hen jazz h istorians trace trends in piano
styles, t he section u sually a llotted to t he
Harlem str ide sch ool ends w ith t he citation
of Fats Waller as its crown ing rep resentative.
His debt to James P. Johnson and others is
pointed out, and t hen the chapter and an era
are brought to a close. Harely does his name
reappear as havi ng influenced younger pian ists
and, u nhapp ily, none of t hem h as success·
fu lly incorporated a ll h is many attribu tes.
Of late, his exuberance a nd ready wit h ave
cropped up in per formances of Hed Garla nd,
notably on m .lly Boy, with Miles Davis a nd
in h is own a lbums. The most recent is f ull
of yet another element. In the notes accompanyi ng s ixteen reissues from his father's
legacy, it is expressed by l\lau rice Waller,
who remembers s itting "l isteni ng to him play
a t h ome until fo ur in the morni ng, sometimes.
That's wben he wasn't entertaining, j ust
play ing. From these evenings I know w hat
he was t ry j ng to say. '\'
T hat t h is s ide of ]jis art was too seldom
d isplayed in publi c 01' on records is often
lamented by collecto rs of j azz p ia no. Garla nd
gives a good idea of what a few of the~e
moments mfght be li ke if Waller were ali ve
today and improvising on su ch old favo ri tes
as Rain, S1I1nmerU' lIe, and Stormy l Veat h er.
While it is true that Paul Chambers, ba~s.
and Art Ta~'l or, drums, take much of t he
burden off t he left hand, he is one of t he
Horace Silver: Finger Poppin'
Blue Note 4008
~'he title t une is Horace Silver's cu rrent
display p iece and it is just as well to have
it p reserved in t hi s reco rdi ng as t he fastmoving in tricacies can sca rcely be abso rbed
in a club performance. T he pian :st's slower
compositions are equally memorable. especially a smoky blues. Come On Home, and a
moody ball ad, YO'lL HalJp en ed My Way, which
call s out for a set of lyrics. T hey are p layed
by his present qu intet, now touring l~l":1 n ce,
with new members Blue JlIi tcbell, tru mpet,
a nd J u nior Cook, teno r sax.
A remin der t bat too long an interval has
passed s ince Silver'S last solo a lbum is contained in Sweet St1£ff, a t rio number with
bassist Gene T aylor and drummer Lou i~
Hayes. Strongly lyr ical, it exposes another
aspect of hi s talent in t he best moments oC
t he set. His other originals are a med ium
bl ues, a samba, a nd II fast jump t une to end
it a ll.
Sonny Rollins: Newk 's Time
Bl ue Note 4001
Harry Edison: Sweetings
Rou!etta R52023
Just what is meant by tl.ie personality of a
jazzman, as opposed to t he jazz personal ity,
can be dedu ced f,'om a study of Sonny Hollins
a nd Har ry E d ison. A It hough t hey go separate
ways to achi eve t heir ends. eacb makes his
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63
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point through persuasiveness of style and
Ideas rather than individual dominance. A
leading figure on tenor sax, Rollins still lays
the creative process bare in every performance,
inviting the listener to participate in his
musical progress. This can be a challenge, as
In Kenny Dorham's Asiatio Raes, or lead to
the pure delight of Namely You, and Wonderful! WOtwerful! A high point is Surrey With
The Fringe On Top, where his only partner
is Philly Joe Jones. He returns the compliment by dedicating a blues to the drummer,
on which he is abetted by pianist Wynton
Kelly and bassist Doug Watkins in effective
soios.
Harry "Sweets" Edison left Count Basie
when the ranks dispersed in 1950, eventually
finding lucrative employment in Los Angeles
studios, where the muted tones of his trumpet
backed countless vocalists. An urge to open
up his horn and appear on his own, last fall,
led him to leave the.se comfortable surround·
ings behind. With Jimmy Forrest, tenor sax,
and a varied rhythm section, he again brings
his intimate style to full fiower on seven tuneful standards, and four originals. One evolves
his nickname into the album title, and another, Oenterpieoe, performs a similar function for Willow Weep For Me.
Chico Hamilton: Ellington Suite
World Pacific WP1<258
Prestige 7147
Basie Reunion
Count Basie & Joe Williams: Memories
Roulette R52021
Ad-Lib
After bringing Shad Collins back to the
studios for one pleasing tribute to Basie,
Prestige becomes more ambitious. on an en·
core. adding a second trumpet in Buck Clayton. Jack Washington's baritone sax, imported
from Oklahoma, joins the tenor sax of Paul
Quinichette, and Eddie Jones replaces the
late Walter Page on bass. Some of the sharp
impact of the first session is lost in the proc·
ess, but the octet is better equipped to
handle John's Idea, and Roseland Shuffle. The
trumpet duo carries away the honors, generating sparkling choruses on Buster Smith's
Blues I Like To Hear, and Clayton's Love
Jumped Out. Congratulations are in order on
a fresh combination of present and former
Basie personnel and it is hoped this series
will continue to explore numerous other possibilities.
Basie opens one avenue by staging a r~·
union of his own--one informal enough to
extract rare guitar interludes from Freddie
Green. Alumnus Harry Edison is welcomed
back to the East Coast, and his trumpet
obbligatos soar gracefully behind the vocal
line. The dozen songs are memorable hits of
another day, polished to a rich lu~tre in Joe
Williams' best ballad style, and Include All
Of Me Oall Me .Darling, and Sometimes I'm
Happy: Lunceford graduates George Duvivier,
bass, and Jimmie Crawford, drums, comple~e
:the party. But jazz fans .will return to It
.,time and again for those few choruses from
Grcen, who enhances both discs.
First let it be said that this is. the original
ChicO Hammon group; with paul.Htirn· added
on:flute and alto s~, engaged, ,m a pr03ect
which' drew it~ atUmti{)D baalt. when ' the
Quil!tet was.formed in 1955:' EllingtQI\com·
positions figured' ill' the drummer's programs
from the beginning, and now eleven of the
most melodic are given an orderly arrangeEd McCurdy: When Dalliance Was In
ment by bassist Carson Smith. They derive
Flower, Vol. 3
Elektra 160
from .what many consider to be his best
period, a point midway in his career which
A Night At The Ash Grove
saw the development of Take 'The A Tmin,
World Pacific WP1254
Perdido, In A Mellotone, Azure, and In A
Sentimental Mood. At least, It is the best
The fifteen assaults upon a malden's virtue
period to explore In a time when even the
encased here reveal that Ed McCurdy merely
composer's present organization is unable to
scratched the surface of his subject In the
recapture the intensity of his earlier works.
two preceding yolumes. He delves a little
Buddy Collette,limiting himself to .tenor
deeper this 'tinie into' the mores of a bygone
and alto sax, shows his close affinity to Ellingage, as a perusal of the enclosed text will
ton and proves again that he would make a
show, and comes up with some of his most
valuable adjunct to the band. Jim Hall's solo
effective work in the series. He accompanies
guitar passages hold much interest, while the
his lusty baritone voice on guitar, with Erik
sound is enriched by the full cello tone of
Darling adding the support of either guitar
Fred Katz. Smith connects each piece, alld the .or banlo. The more serious student might notp
performance is uninterrupted. Thebesi: from
that Ii symbolic reference to. nails In Old
the Quintet In ages, it will probably remain
Brass To Mend, a Tinker's tale, turns up 0
so, unless Hamilton holds another reunion and
few cen turies later in Cripple Clarence Lof·
returns to Ellington, this time with Collette . -ton's You've Done Tore Your Play House
also playing clarinet.
.
·1i'Q'wn.
As an antidote to this reyelry there Is
Barbara Dnne's doleful imprecation Away!
AndrePreviil Plays Songs. By,.V.rnon. Away!
With Rum, By Gum! Complete with
Duke
Contemporary C3558 . SalYation Army' bass drum, it introduces a
typical evening of coffee house music In Los
Freddie. Gambrell:: Pjano:'.· ".':.'
.
. . Worid. Pacific'WP1256 Angeles. Other folk singers on the program
at the Ash Grove are Rolf Cahn, Lynn Gol<1,
Both albums' are' noteworthy for pianists
and the team of Bud Dashiell and Travis
who, rather than take liberties with. tried
Edmonson. Heard as accompanists are Carl
and familiar tunes, find fresh conceptions to
Granich. Sol Gold, and Carl Sandbag. They
renew them. Some are wholly transformed
engage in a lively summary 'of all the unex·
in the process, a treatment heartily· approved
pected things likely to happen in the vicinity
by Vernon Duke, who admits to one superof on espresso machine.
visorysuggestion in his liner notes--an admonition that Andre Previn "go berserk" on
Apr'il in Paris. The composer also applauds
the inclusion of the verse, along with the
Italy: Its Sounds And People
neglected Ages Ago, and Round About. When.
Capitol T1 0186
ever you hear one of the ten songs in the
The
tolling
in
Vatican
City
of the great
set after this, you are likely to find yourself
bell of St. Peter's Basilica begins the first
returning to Previn for further elucidation;
tour in sounds of Italy to be recorded. It
It should be stressed that the piano is solo, a
extends from the Swiss border, where n
distinction necessary when trio and quartet
Lombardy
choir sings an Alpine folk song, to
efforts are falling into the category. It is
Naples in the South for a view of the harbor.
Previn's first such venture, and he does have
There Is a choice of a Vespa or Fiat to escape
a left hand.
the Rome traffic and travel out the Via Appia
Freddie Gambrell, borne up by the plaudits
Antica, past roistering :flocks of swallows, to
for his first appearance, is not quite as
hear the nightingales. The Milan subway
startling in his second. The blues are left
behind for a program designed to please the
leads to Corpus Domini ceremonies at th ..
managers of plush bistros where he might like
Cathedral in which Columbus once wor·
shiped,' Abbruzzo shepherds dance to a lively
to play. If that goal is reached, this LP will
mazurka and Sicilians engage in a tarantella.
be a bargain compared to the tab, and there
Also the usual airport, railroad terminal and
is much to enjC)y in Anything Goes, Without
A. Song, and Ind,an Love. (Jail. His three
more bells, from St..Tohn Lateran, St. Paul
Outside The Walls alld St. Mary Major. Pro·
originals, along the same vein, otrer a waltz,
duced by Dave. Dexter in collaboration with
moonligh_t ~amblings .on 0Ptt.s 116, and a
Roger Degoy of La Voce del Padrone, it is
cute Who You' The piano dynamics and Ben
narrated hy Annahella Carta.
.1E
Tucker's bass viol are handsomely recorded.
AUDIO
64
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•
JUNE, 1959
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AUDIO
•
65
JUNE, 1959
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AmericanRadioHistory.Com
Audio in the Theatre
HAROLD LAWRENCE ':'
C1£stomel': May I have that new album
of carillon music you've got in your window~
Salesman: Would you like the "mono"
or the "stereo" version ~
C1£stomel' (after some deliberation): I'll
take t he monophouic. After all, how stereo
can chimes be ~
The customer in this true conversation
might seem a bit uninformed in our audioenlightened age, but don't judge him too
severely. H e may have little more than a
hazy idea as to wh at constitutes an authentic stereo recording, but he seems roughly
aware of basic differences between monophonic aud stereophOllic sound. And, as any
record salesman will tell you, the aver age
record buyer thinks of the stereo disc as
having made obsolete the "hi-fi" l'ecord.
Dedicated audio enthusiasts wince at
these now familiar mauifestations of the
prevailing ignoran ce over t he meauing of
stel'eo and so und r eproduction generally.
L ack of Imowledge on the part of the
general public can be excused. There is no
excuse, however, for the failure of those
people engaged in the business of entertainment to take full advantage of the
enormous strides which the manufacturers
of audio eq uipment and the sonnd engineers have made over the years toward
better and tmer sou nd reproducing techniques.
Have yo u ever noticed the reaction of a
movie audience to a film that is poorly
focused ~ Before the operator has had a
chauce to grab the focusing knob, footstamping, whistles, catcalls, and r aucous
shouts fill the theatre. But offer t his same
audieuce galloping audio distortion and it
will sit back, t horoughly r elaxed, contentedly munching chocolate-co \' el'ed peanuts.
Where it concerns audio in public places,
th e general public is strangely oblivious
to the most flagrant abuses.
Speech Reinforcement
Some SLX years ago, the dinlinutive
French popular singer, Edith Piaf, made
her Carnegie Hall debut. Those who were
not familiar with her career in th e Parisian
"music-halls" thought that she had made
a serious mistake in hiring such a large
hall for her one-man show. How co uld she
hold an a udience's attention for an entire
evening ; a nd wouldn't her warm and vibrant personality be dissipated in Carnegie Hall's vast oceans of space~ The
critics proved wrong on both counts. La
Meme Piat appeared on stage wearing her
simple black dress. With her hair combed
in no special manner, she looked the antithesis of tIle "glamour girl." But she
,. 26 W. N'inth St., New YOl'k 11, N. Y.
66
needed no accessories to conquer her
p ublic; even before she began her fil'st
number, she had each person in the hall
sitting on the edge of his seat, thoroughly
captivated by Piaf's wonderfully expressi ve features.
For this listener, however, the spell was
broken once the concert began. Piaf, it
seems, thonght it necessary to employ a
microphone throughout the program, though
there was no need for electronie amplification. 'rhe orchestra was placed discreetly
behind a cmtain toward the rear of the
stage; but even if it were l'ight out there
alongside her, P iaf would never have been
in real t rouble. Iu any contest betweeen
the c hante~£se and a band, the former's
impressive lung power wonld easily have
enabled her to soar above th e competition.
Apart from the fact that the microphone
could ha \'e been dispensed with, Piaf, unlike such skilled microphone mauipulators
as J ean Sablon, misused the instrume11 t .
In fact, she did evel'ything but bite it; her
"p's" exploded like minor charges of TNT,
her "s's" resembled an overworked boilel',
and her high notes shattered like the
cymbal clashes of the Coldst ream Guard .
The l'es ult was a sonic nightm are creat ed
by the ar tist's unprofessional use of th e
micropho11e and the pOol' quality of th e
playback system in the hall. 'l'his unfOl'tu nate pattei'll of audio distress is a f amiliar
pal't of the night club and theatrical wOl'ld.
One of the mOl'e disturbing aspects of
the contemporary legitimate theatre is th e
use of tape and disc r ecording for background and incidental musk Off-Broadway
producers frequently utilize classical l'ecords, seldom with any marked success. For
example, Respighi's highly evocative "Pines
Near A Catacomb" from Pines ot Rorne
preceded Act II of Th e Playboy ot the
Western W m'ld at the Cherry L ane Theatre's r evival of Sean O'Casey's playa few
year s ago. The choice of Respighi's score
could not have been more inappropriate to
the Il'ish subject. To make matteI's worse,
the playback equipment was of shockingly
poor quality; the record itself sounded as
if it had been borrowed from a circulating
disc libmry ; and the system was being
played at an abnormally high level for a
theatre whose seating capacity is approximately 300.
On-Bl'Oadway pl'oductions have their
audio pl'oblems, too, despite higher budgets.
When Paul Bowles composed evocative
incidental music for T enuessee Williams'
Sweet Bil'd at Y01£th, the entire score was
recorded in advance of the play's opening
to be played back in recorded fOl'm during
the run of the production . Bowles' intention was to convey ' the special haunting
"music" of a lazy Gulf town. H e would
have succeeded brilliantly were it not for
AUDIO
www.americanradiohistory.com
AmericanRadioHistory.Com
•
JUNE, 1959
the fact that an inferior playback system
and an unreasonable choice of playback
level combined to transform the subtle
effects he aimed for into loud and vulgar
sounds.
Last month, the Bolshoi Theatre Ballet
Company concluded its triumphant New
York visit. One of the highlights of its
run was Prokofiev's Romeo and Juliet. The
crush for tickets was overwhelming, and
several hundred thousand requests for seats
were actually turned down. One of New
York's art movie houses jumped on the
Bolshoi bandwagon by presenting a filmed
version of Prokofief's ballet with the same
company. The sound track was totally unworthy of the film's visual attributes,
which were truly impressive.
"Art" Film Sound
It is a sad commentary on the "art" film
to note that the sound engineering lavished
on a "Western" is usually superior to
nearly all "cultural" cinematic efforts, a
notable exception being Walt Disney's
Ji'antasia. Perhaps the public that attends
art movies and the legitimate theatre (as
well as opera, ballet, and symphony e,oncerts) is, on the whole, indifferent to good
sound reproduction. How else can one account for its permissive attitude towards
inferior recording and playback techniques'
The answer may be found in the history of
recording. In the 80-odd years since Edison
devised his tin-foil phonograph, listeners
have been content to accept unreasonable
facsimiles of "live" performances. To make
up for sonic deficiencies, the mind "equalized" the recorded performance. This form
of equalization is undoubtedly still being
brought to bear, unconsciously of course,
in the above-mentioned cases, as well as in
countless other similar situations. The fact
that the public makes this mental adjustment to mediocre sound indicates that it
does not expect good sound-that is, the
standard of quality of which today's burgeoning audio world is fully capable of
producing. If it expected it, it would certainly demand it.
IE
Concerning Electrostatics ..•
Among the many high frequency speakers available today, we believe the electrostatic merits special consideration for the serious
listener. This is not to imply that all electrostatics automatically
guarantee superior reproduction. When properly designed and
carefully manufactured, however, the push-pull electrostatic will
outperform all other types of tweeters in terms of low distortion,
excellent transient response, and wide range - qualities most im~
portant to serious listeners.
As a guide for ,prospective purchasers, the manufacturer of the
JansZen has compiled the following most commonly-asked questions about electrostatics:
Q. What are the basic differences between electrostatics now on the
market?
A. Electrostatic speakers all utilize the
electrostatic principle, but there the
similarity ends. Three commonly-used
electrostatic designs are shown below.
After long and continuing tests of all
types, JansZen believes that only the
push-pull design really meets high fidelity requirements. Its balanced and
opposing electrostatic forces operate
simultaneously on both sides of the diaphragm - one pushes while the other
pulls - to give precise control over diaphragm movement. In single-ended and
double-single-ended designs, electrostatic forces acting on only one side of
the diaphragm cannot provide the degree of control necessary for good transient response and low distortion.
176 SHEATHED
CONDuCTORS
bo
o
o
o
o
o
o
0
0
0
0
0
0
0
./
ELECTRODE
~
./
ELECTRODE
I1
DIAPHRAGM
DIAPHRAGM
DIAPHRAGMS
JansZen true
Push-Pull
Electrostatic
Single· Ended
Electrostatic
Double·SingleEnded
Electrostatic
Q. JansZen literature stresses "virtually
RECORDS
(from page 59)
that had America danCing all over the place
to the big-band swing sound. But there's more
than a recreation here, for the style is still
second nature to these players. It's not too
late to recreate.
I didn't dance then and would have thought
I had never absorbed this kind of music at
all. I was really a bit startled, then, to find
how familiar it sounded-and how much a
thing of the past. It's a plain fact that jazz
and pops together have already left this
swing phase far behind (even though It can
easily be brought back on special occasions)
and the stull' we hear today Is seldom anything like it. Interestingly dated.
Stereo Is good for big-band sound; It's tops
for historical realism, bringing out here the
very sound of a huge dance hall In vivid
terms. The band Is right In that hall, spread
out from side to side but oft' from the mikes
and, ever so clearly, up on that fancy stage
in front of the big floor. Yep, the locale is
beautifully suggested-and isn't the locale
as Important as the swing stuft' Itself? One
couldn't exist without the other. ,Good job,
Everest.
IE
AUDIO
•
massless diaphragms" and" sheath~d
conductors." Don't all electrostatlcs
have these?
A. No! The JansZen diaphragm is the
thinnest, lightest, most chemically
stable material used in any electrostatic. Thus it has virtually no inertia
to resist the electrostatic forces or to
produce hangover, distortion, or poor
transient response. The sheathed c<?nductors are another JansZen exclUSIVe
that contribute materially to long,
troublefree life and lowest distortion.
88 sheathed conductors, stretched taut
on either side of each diaphragm, provide the controlling push-pull electrostatic forces. Tolerances as close as
l/lOOO-inch are rigidly maintained during the several hours required to assemble each JansZen radiator.
Q. How durable are electrostatic radi-
ators?
A. JansZen's patented sheathed c<?nductors and chemically stable dIaphragms cannot oxidize - a potential
source of electrical breakdowns. Radiators are thoroughly protected by rigid
styrene frames and placed well behind
the grill cloth. No potential trouble
spots have been found during J ansZen's
continuous accelerated life tests which
age tweeters 10 years in 1; hence
a straightforward 2-year written warranty is furnished with every JansZen.
Q. JansZen electrostatics are called
"mid/high range" tweeters. Exactly
what does this mean?
A. While most electrostatics are limited to frequencies above about 5,000
cycles, the response of the JansZen extends down through the mid-range of
700 or 500 cycles depending on model.
Thus, the JansZen may be used with
any good woofer withQut ,the need for
a costly separate speaker and crossover network to handle middle frequencies. The wide range of the JansZen is
not achieved without cost, however.
Extra care in the manufacture of the
electrostatic radiators and larger, more
expensive power supply components
are required to insure that mid-range
response retains the same transparent
clarity that makes the JansZen so desirable as a high frequency reproducer.
Q. What is the purpose of the power
supply in electrostatics?
A. In the dynamic speaker, a magnet
furnishes the force to move the cone.
In the electrostatic, the power supply
furnishes "plus" and "minus" voltages
to move the sensitive diaphragm. Special transformers in the JansZen power
supply provide a step-up ratio which
remains uniform from the critical midrange to beyond audibility. This assures flat response throughout the wide
frequency range encompassed by the
JansZen-and with less than 0.5% total
distortion.
Q. Aren't electrostatics quite inefficient?
A. The unusually flat response an!'!
wide range of the JansZen may make It
seem less efficient than a less uniform
tweeter whose efficiency is measured at
some peak in the response curve. The
J ansZen can be used with any good amplifier capable of-2001"m?re clean.watts
output. When companng effiCIency,
note that the JansZen requires no
power-robbing attenuator pad in 1:be
woofer circuit; it readily balances WIth
most good low frequency direct radiators.
JansZen'
*tnc/udtng destgn.s by ATtilUT A.Jan.szen' and made only by
NESHAMINY ELECTRoNIC CORP. Neshaminy, Pa.
67
JUNE, 1959
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AmericanRadioHistory.Com
NEW P·RODUCTS
• Stable Audio Oscillator. Stability exceeds 1.0 per cent and frequency response
is within ± 1.0 db over a range of 30 to
15,000 cps in the new Model 200 a udio
oscillator recently introduced by Barker
& Williamson, Inc., Bristol, Pa. Harmonic
content is very low. The 200 generates a
maximum 10-volt outp u t into a 500- ohm
load. At 5-volt output distortion is less
than 0.2 p er cent. Control s are incorporated
for adj u sting freq u e ncy and output. No
zero reset or line calibration is required,
an d dial calibration is accurate to + 3.0
per cent of scale reading.
-F-l
channel separately, or simultaneous bass
and s imultaneou s treble ad justment for
both channels. An a utomatic shut-off permits the record changer mechanism to also
turn off the amplifier after playing the
final record in a stack. The 240 has a total
power output of 30 watts, 15 watts per
channel. Freq u ency response is 20 to 20,000
cps ± 1.0 db. Harmonic distortion is less
than 1.0 per cent. Sensitivity is 3.0 mv for
phono and tape-head inputs, 110 mv for
tuner and tape recorder. RIAA equa lization
is automatic, while LP, NAB, AES, and
tape h ead eq ua lization is provided at calibrated points on the tone con trols. The nine
front-panel controls for the 240 include:
Input Sel ec tor, Mode (including Stereo
Reverse), Volume/ Power On- Off, L oudn ess,
Stereo Balance, Bass, Treble, A u tomatic
Shut- Off, and Speaker Selector. Manufact ure d by Pilot Radio Corporation, 37-0 4
36th St., Long I s land City I, N. Y.
F-3
• She·r wood FM Tuner. The n ew Model
S-3000 II FM t un er features " Inter- Ch annel
H u s h," a n e w circ uitry which adds to the
convenience of FM tuning by muting the
noisy "hash" normally heard between
stations on highl y sensitive t uners. The
instrument is also provided with a front
panel control to a djust the degree of
s ile n cing without affecting the tuner's
sensitivity. The Sherwood FM tuner ci rcuit
• Prest,o Ste·r eo Cutting' Head. This new
disc c utting head, Model Sl, has absolute
stability from 30 to 20,000 cps, giving a
totally u seful band width without peaks
or dips. A new Presto -designed feedback
coupl~ng techniq u e permits recording at
previously un obtainab le levels. with distortion v irtually unm easu rab le. A unique
a re stated by the manufactur er to have
smooth r esponse from 20 to 2 0,000 cps,
with u sab le output to 35,000 c ps. They are
composed of four independent, concentrically placed radiators, each d es igned
for maximum p erforma nce with in its portion of the a udio spectr um . Tw o Trebax
tweeters are angled to the polar axis for
wide dispe rsion of the high s. All Tetraxiom and Triaxiom models are built on
rigid die-cast c h a ssis to m aintain op timum alignment of the high-precision
radiators. Goodmans spea kers are di s tributed in the United States by Rockbar
Corporation, 650 Hal stead Ave., Mamaroneck, N. Y.
1'-6
• Triad Power Transformer. Development
of voltage - doubler circuits using silicon
r ectifier power s u pplies is facilitated with
the new Triad Type R-93A power transformer. It provides taps on both primary
and secondary win dings to a llow several
variations of output voltage, an d is electrostaticall y shielded. Rated at 110/120
volts 60-cycle primary, and 150/ 160/170
is extremely sensitive, stated by the manufacture r to be 0.95 microvolt for 20 db
quieting. Automatic frequency con tro l with
18 db correction simplifies accurate t u ning.
Front panel AFC disabling switch is incorpor ated for use w hen r eceiving a weak
station ad jacent to a strong signal. Fre quency response of t he S-3000 II is 20 to
20,000 cps ± 0.5 db. Both intermodulation
an d h armonic distortion are well under
0.5 per cent at 100 per cent modulation .
Sherwood ;Elec~ronic L aboratories, Inc.,
4300 J. Callforma Ave., Chicago 18, Ill.
1'-4
suspension
system
provides
superior
cross-ta lk charac teristics. Presto's "Studio
Oriented" design permits quick change of
stylus, with no j~g or fixture require d for
alIgnment, and wlth no n eed fo r removin g
the head from the feed mechanism. The
Sl fits all Presto disc recording lathes and
a ll other professional la th es as well with
mounting kits availab le where necessary.
Manu factured by Bogen-Presto Company
Param u s, N. J.
F-2
• Pilot Stereo Contro1-AmpUfie,r . Th e new
Pilot Mode l 240 is a modestly priced dualchannel stereo preamplifier-am plifier. Each
channel of the unH has five i nputs, includmg two pairs of phono inputs fo r conn ec-
tion of both a record changer and a turntab le, with provision for the u se of either
by means of the selector switch. The remaining t hree pairs of i nputs accommo d ate
FM-AM, multiplex, and tape recorder. '1'he
exclus ive Pilot TroLok tone controls permit treble and bass adjustment for each
• Stromberg- Carlson Stereo Preamp. A
com plete stereo control center, this new
p r eamplifier, Model ASE-434, fea tures
Stromberg-Carlson's "Stereo T one Bal a n ce" signal. This e nab les the u ser, s imply
by flicking a switch, to introduce a n a udib le signal into each stereo ch an nel, so that
the two chann els can be balanced uncler
vol ts at 500 ma secondary, the R-93A also
supplies filament power of 6.3 volts at 6.0
am ps, center-tapped for hum reduction. I n
a voltage-doubler circu it, the maxim u m
d.c. availab le for preamps and amplifier s
i s 250 ma at approxim ately 480 volts. A
product of Triad Transformer Corporation
4055 Redwood Ave., Venice, Calif.
1'-7
actual operating e n v ironm e nt. Separate
b~ss, treble, an d volume controls are provlded for each c h annel. Selec tion of RL....A
or NARTB equalization is provided by
switch settings, an d scratch an d r u mbl e
filters may be switched in or ou t. A phan tom output (mixed A and B) is a lso pr()vided. Manufactured by the Stromber~­
Ca rlson Division of General Dynami~s
Corpc.ration, Rochester 3, N. Y .
F-5
• Goodm.a.ns Speaker Systems. Two new
speaker systems recently introduced int o
the American m arket are the " T etraxiom"
and t h e "Triaxioffi;," unitized 4- and 3-way
systems, respectlvely. The Tetraxiom
i llustrated, is entirely uniqu e in both
deslgn . and construction, while t h e Triax~<!m I S more conv,:,ntiona l. Both systems
utlllze the new "Rlgidflex" cone with a
flexible, free -fl oating edge a nd rigid cen ter to prov!de pure piston action. Tht'
two T e traxlOm mode ls a nnounced are
rated at 40 a nd 50 watts, respectively, and
68
• Heathkit Ste,r eo System. Complete in
ever~ d etail-including cabinetry, stereo
am plIfier, record c hanger, stereo cartridge
and three speakers-this newest Heathk it
stereo package can be ready to play after
only a few hours assemb ly time. The
AUDIO
www.americanradiohistory.com
AmericanRadioHistory.Com
•
JUNE, 1959
NewH.H. Sco·tt
amplifier e mployed is the "s um a nd diffe r e nce " a mplifier d eve loped by CBS L ab oratorIes an d first d escrib ed p u blic l y in
t h e October, 195 8, issue of AUDIO. It is
licensed excl usive ly in kit form by H eathkit. The system utilizes a centr a lly located
woofer, mounted in the equipment console
for r e produ c tion of the non -dire ctiona l l o~
f req ue ncies, a nd two exte rna l "wing"
s peak ers for t h e higher frequen cies which
proVid e stereo effect. The a mplifie r em pl oys onl y fo ur t ub es an d is e xtreme ly
easy to assemb le. Control s co n sist of on off. sw itc h , bass a nd treb le, input sel ector
sW lt.ch, an.d level-ba la ncing a d justm e nt.
AvaIlab le In e i ther birch or mahogany
the SD-1 stereo kit r e prese nts excell e nt
valu e in both performa nce a nd styling.
Full information will be m a iled free up on
req u es t t o. The H eath Company, Benton
H a rbor, MIch.
1'-8
• Blonder-'l'ongue Flirt Booster. This is the
fir s t broa d-ba nd FM amp lifier to utilize
the l ow -n oise, high-gain a nd l o n g-life
<:haracteristics of the n e w T ype 6ER5
1'rame~grid tube. Developed to improve
receptlOn of even t h e most se n sitive FM
tune r s, the unit d e livers 16 db uni fo rm
gain on a ll stations in th e 88-l 08-m c
range. Th e a mplifier may b e located up
to 600 feet from the r emote co ntrol unit
Stereo Amplifier has
features 'never before
offe'r ed at $139. 95 *
The 'new H.H. Scott 24 watt sterebph<?nic amplifier, Model 222,
puts top quality within tl1e reach of all. This new amp.lifier has many
\
.
features never before available for less than $200. It
backed by
H. H. Scott's fine reputation. Check the f eatu ('es b~
see why you should build' your new stereo
H.H. Scott Model 222.
n ear the FM r eceiver. Built- in mu l tipl ex
c ircuits permit sim ulta neous t ra nsmissi on
of a .c. a nd r.f. over a si n g le 300-ohm l ine .
The booster is hou sed in a lightweight
a luminum cabinet for w eather protection,
wit h a swing-down c h assis for easy main tenance. The a mplifier we ig h s les s tha n
five pounds a nd the rem ote uni t w eighs
on l y two-a nd- on e-half p o unds . A descriptive bulle tin, Form HAC- lOO-3 9, on a ll
B londer-Tongue consumer FM products is
available on request. Write B lo nderT ong ue L a boratories, In c ., 9 A llin g St ..
Newark 2, N. J.
1'-9
• Ri-Fi Cabinetry. A n e w li ne of equipm e nt cab in ets a nd s peaker e n c losures, to
b e sold direct to consu m e r s only, has been
introdu ced by H omewood Industries, In c.,
Equalization switch lets
you choose between
RIAA compensation for
monophonic and stereo
records ; NARTB, for
tape heads/
Sepa rate Bass
Treble controls
each channel let you ,
adjust for differences
in room acoustics and
different speaker systems.
Effective scratch filter
improves performance
on older worn records
and improves reception on noisy radio
broadcasts.
Specia l switch positions for accurate bal ancing, for playing
stereo, reverse stereo
and for using monophonic records with
your stereo pickup,
This position lets you
play a monophonic
source such as an FM
tuner or a tape recorder through both
power stages and
speakers.
Exclusive centerchannel output lets you
use your present amplifier for 3-channel
stereo or for driving
ex tension spea kers .
Separate stereo taperecorder outputs.
I
Channel balance control adjusts for different speaker effi·
ciencies and brings
channel volumes into
balance quickly and
easily.
Master volume control
adjusts volume of both
channels simultane'
ously. Also functions as
automatic loudness
control whenever de·
sired.
SPECIFICATIONS: Dual 12 watt channels; 0.3% I M dis·
tortion; 0.8% harmonic distortion ; frequency response 20 to 30,000 cps; extremely low hum level (-80db ): DC operated preamplifiers heaters ; Inputs for
stereo or monophonic recorders , tuners, phono cartridges and tape heads.
Phono sensitivity 3 mv. Sub ·sonic rumble filter prevents overload from noisy
chan gers or turntables.
Price $139.95*
H.H. SCOTT INC.
Dept. A-6. 111 Powdermill Road, Maynard, Mass.
Export: Telesco International Corp.,
36 W, 40th St., N.Y,C.
Insist on genuine ~ Scott components.
*West of Roclcies $1 ~8, 25, Accessory case extra •
•••••••••••••••••••••••••••••••••••••••••••••
SEND NOW FOR
FREE HI-FI GUIDE
26 Court St., Broo klyn I, N . Y. Available
both in kit form a nd facto r y assembled,
m ost units are built of selected bir c h and
pop la r, a l t hough some a r e mad e of w a lnut
a nd oi led walnut as well. F eatured in the
line is a 36-in.-w ide eq uipm e nt cabinet,
AUDIO
•
AND CATALOG
•••
••
·•
JUNE, 1959
www.americanradiohistory.com
AmericanRadioHistory.Com
Rush me complete details on your new Model 222 and
your complete 1959 Hi Fi Guide and Catalog.
Name,______________________________________
Address,___________________
City _________________ ,State,_ _ _ __
Sound
Tall{.
by John
K: Hilliard
Director of Advanced Engineering
LOUDSPEAKER EFFICIENCY
Loudspeaker efficiency is an important
design factor that is often overlooked or
misunderstood by those who enjoy high
fidelity. It is only logical to assume that
any device should be engineered to be as
efficient as possible whether it is an auto
engine, an amplifier or a loudspeaker.
Speakers which have very low efficiency
were not designed with that feature in
mind. Rather this low efficiency is a
by-product of one of the simpler and less
expensive engineering methods used to
achieve bass response and low distortion.
Such designs, in an effort to achieve greater
bass and low distortion, utilize a heavy
cone which has inherently low resonance.
This heavier mass provides greater bass
but carries with it the high price of poor
transient response, loss of mid and highrange efficiency and smoothness, and
heavier amplifier requirements.
Many speakers following this design
approach require as much as 16 times the
amplifier power to obtain the same listening levels as more efficient units. Ten watts
versus 160 watts seems like an extreme
design compromise. Few, if any, of the
stereo amplifiers will provide sufficient
power for full dynamic range at normal
listening levels with such low efficiency
speakers.
With a more carefully integrated design
approach, and the acoustical laboratories
necessary to truly evaluate results, it is not
necessary to make this compromise to
achieve bass. A properly designed magnetic structure will provide a strong flux
throughout a long air gap. Cones, with
their compliance and voice-coil designed
for long linear excursion throughout the
audio range, will operate in this high flux
with great efficiency. Such a design has low
distortion and good bass without any compromise in efficiency or transient response.
All ALTEC speakers are the result of such
integrated design principles. Their bass
reproduction is in proper balance with the
rest of the audio spectrum. Their distortion and transient response have received
careful attention. Their efficiency is as high
as present engineering art permits.
It should be remembered that a good loudspeaker design need not sacrifice a part of
the whole performance in order to provide
a single outstanding feature.
Listen critically at all levels of loudness.
You will readily distinguish the superiority
of ALTEC loudspeakers.
.
Write for free catalogue: ALTEC LANSING
CORPORATION, Dept. 6-A , 1515 S.
Manchester Avenue, Anaheim, Calif., 161
Sixth Avenue, New York 13, N. Y. 12.39
Circle 70A
factory assembl ed, s uitab le for housing a ll
standard compon ents. An assortment of
matching speak er enclosu re kits feat ure
assemb l y short- c u ts to assure trouble-free
constr u cti on. All bracing cl eats are pre attach ed at the factor y. A free illustrated
catal og will b e mailed upon written request.
1'-10
What's In It
For You?*
• Flutter Mete,r . This sensitive measuring
device was engineered to comply with the
stan d ards set by the Society of Motion
Picture an d Television Engineers for fiuttel' an d wow. It is designed to fill the n eed
for a rapid and accurate method of obtaining visua l indication of wow and flutter content of a ll ty pes of tape recorders
a nd playback equipment including 33-1 /3 -,
45 -, and 78 -rpm discs and 16- and 35-mm
sound film mechanisms. A built in preamplifier and input atten uator will accept
potentials ranging from 1.0 millivolt to
100 volts. Flutter an d wow are measured
t hro u gh hi gh- and low-pass filters, respectively. A built-in 3000- cps oscillator
permits the in strum ent to be u sed with-
o ut the need for calibration a nd the use of
external oscillators. A t h ree-range filter
is included to study an d isolate flutter and
wow components. Three scales-0.3, 1.0,
an d 3.0 per cent are calibrated for flutter
an d wow. Significant readings can be
made d ow n to 0.01 per cent with reliability. Con t rol s on the panel con sist of an
input voltage selector, a vernier calibra tion adjustment, a capacita nce balancing
control to compensate for differences in
lin ear speed s of tape mechanisms, turntables an d film eq uipment. a filter selector
a nd a scale se lector switch. Comple t e technical s'pecifications may be obtained by
writing to Amplifier Corp. of America,
Instrument Division, 398 Brodway, New
York 13, N. Y.
1'-11
• Universa.l Impeda.n.ce Bridge. The Type
1650-A impedance bridge is a highly accurate instrument for the measurement of
the inductance a nd storage factor, Q, of
inductors, the capacitance an d dissipation
factor, D, of capacitor s, an d the a.c. and
d.c. resista nce of a ll types of r esi stors. It
r e places General Radio's popular Type
650-A impedance bridge, offering wider
range an d greater accuracy. Th e n ew
model h as completely new e lectrical an d
mechanical design . One important feature
"' Better performance . . . with a
TELA D I
CONDENSER MICROPHONE
A precision instrument built to rigid standards .
A professional " condenser mike" for wide
range reproduction under various acoustical
conditions and yet sanely priced to meet the
budget of any studio or serious amateur.
• Variable Output
• Selective Patterns
• High Recognition Factor
Send for full particulars and name of your
nearest dealer.
Sale importers fa" th e United State8
~~UIII~
SOUND
NT
COMPANY
80 W. 55 St.
New York . N. Y.
Circle
703
IF YOU ARE MOVINC
Please notify our Circulation Department
at least 5 weeks in advance. The Post Office
does not farward magazines sent to wrong
destinations unless you pay additional post_
of the 16 50-A is "Orth on ull," an exclusive
new mechanical-ganging device which fac ilitates measurement of low -Q inductors
and high-D capacitors. Orthonull makes
easy m a ny low-Q measurements w hic h are
practically impossib le with some impedance bridges. The instrument is com pletely self- containe d and portable, with
battery-powered, low-drain,
comp letel y
transistorized oscilla tor an d d etector.
Manufactured by General Radio Company,
275 Massachusetts Ave., Cambridge 39,
Mass.
1'-12
70
age, and we can NOT duplicate copies sent
to vau once. To save yourself, us, and the
your old address and your new address.
Post Office a headache, won't you please
cooperate? When notifying us, please give
Circulation Department
RADIO MACAZINES, INC.
P. O. Box 629, Mineola, N. Y.
AUDIO
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•
JUNE, 1959
STANDARDS
STEREO DEMANDED IT!
(from page 52)
mum drift observed during a twohour pehod. If the tuner is
intended for different types of installations these tests should be
repeated for the different thermal
environmental conditions.
(b) The frequency varies with power
supply voltage in a manner that
depends upon the rate of variation of this voltage. The line voltage shall be varied from 105 to
125 volts and the results of frequency drift shall be observed one
minute after the voltage change
has occurred. The amount of frequency drift to a line voltage
change from 105 to 125 volts shall
be stated.
(c) If the receiver has automatic volume control, the variation of signal-input power affects the oscillator frequency indirectly by way
of control circuit. The frequency
drift with variation of signal-input voltage is to be observed after
the receiver has been in operation
a ' sufficient length of time to reach
temperature stability. The maximum frequency deviation from the
signal required to obtain 30 db
usable sensitivity to an output of
100,000 microvolts of the signal
generator shall be r ecorded.
The rated frequency drift is the
maximum frequency drift value
obtained at the standard mean carrier frequency in the tests of
7.05.09.
'\TANNOY/
ENGINEERED IT!
THE NEW "MONITOR" DUAL CONCENTRIC
(the most advanced co-axial to date)
*cuit
New revolutionary magnetic shunt cir.
increasing useful low frequency flux
INCORPORATINC
by more than 20%.
*phragm
Unique treatment of low frequency dia·
surround providing improved reo
sponse and stability.
*high
New
acoustic balance cavity improving
frequency response, reducing dis·
tortion.
Tannoy engineers have produced a speaker of unsur·
passed quality, already being used as a 'Monitor' by world
wide recording, radio, and television companies. The ex·
tended range and increased efficiency of the low frequency
unit make it ideal for use in relatively small enclosures,
whilst still maintaining the "presence" of unres.tricted
sound. This, combined with the fully' integrated sound
source of the 'Monitor' Dual Concentric makes it especially
suitable for stereophonic reproduction.
WRITE FOR DETAILS
TANNOY (CANADA) LTD.,
36 WELLINGTON ST. EAST, TORONTO, ONT.
TANNOY (AMERICA) LTD.,
BOX 177, EAST NORWICH, L. I., N. Y.
Circle 71A
7.05.10 Squelch Control
If the tuner is provided with an adjustable squelch control the tests of Section 6.03.14 are to be repeated with the
understanding that AM terminology is
used.
7.05.11 Loop Antenna
If the tuner is equipped with a loop
antenna the tests of Sections 7.05.02,
7.05.03, 7.05.04, 7.05.05, 7.05.07, 7.05.08,
are to be repeated with the loop antenna
placed in a known electric field. It is understood that in the foregoing sections the
word "microvolts" is to be replaced by the
words "microvolts per meter." For generation of a known electric field, reference i s
made to the IRE Standard On Method of
'resting Amplitnde Modnlation Broadcast
Receivers, 1948, and supplements.
STEB,EO
8.00 Test Procedures, AM·FM Tuners
8.01 Norma l Oontrol Settings
If an AM -FM tuner is constructed to
provide, not only for the reception of radio
signals but is also used to repl'oduce recorded. signals from records, tape, etc., it
has be~n usual engineering pract~ce to provide an' eX,c,ess of audio-frequency amp l~fi ­
cation in these tuners or receivers. If the
test proced nre of Sections 6.00 and 7.00
are followed, serious harmonic distortion
will occur and the test results will be
meaningless. For tuners and receivers of
such a construction the normal control settings shall be as shown in Sections 6.01
and 7.01 except that the volume control be
adjusted to an attenuation of 20 db and
the other controls affecting audio-frequency
response shall be ad justed for the condition
of flattest response as indicated by panel
markings.
If this tuner contains a power output
stage, the rated load resistance shall be the
AUDIO
•
THE
R,.0-6Otft
STEREO SYSTEM
achieves the full , true potential of stereophonic sound.
Roberts superbly designed transport mechanism, with its hysteresis .
synchronous drive motor, provides perfection in pitch - a~d timing
accuracy of 0,2%. This, with Roberts exclusive MultJrase Head,
gives you professional recording quality found only in
far more expensive recording systems.
Complete Stereo System $499
ROBERTS ELECTRONICS Inc.
1028 N. LA BREA AVE., HOLLYWOOD 38, CALIF.
Circle 71 B
, 71
JUNE, 1959
www.americanradiohistory.com
AmericanRadioHistory.Com
NO
w. .. enjoy your HI-FI OUTDOORS
PATIO, GARDEN, TERRACE, PORCH
with the new
WT-6
ATLAS HI-FI
COAX-PRO~ECTOR
all-weather construction . .. install it, forget it! .. .
or take it with you w herever you liste n.
True HIGH FIDELITY TWO-WAY system -not
just a "compromise" of two horns coupled to
a single diaphragm. The WT-6 comprises a
weather-proof cone type driver (with 6-inch
throat) couple d to its individual woofer horn;
. - a separate pressure-type driver loaded to its
separate tweeter horn . The bui It-in crossover
electronic filter supp lements the electro mechanical fr~quency-li miHn g ' characteristics
of the 2 ind ivI dua l reproducers - providing
fo r smooth f r eque nc y division as each
spea ker funct ions within its engineered
range of frequencies.
All-weather ... high efficien cy . . . compact
•.. for all indoor and outdoor uses . . .
uni~ersally adjuotable "U"_type rugged steel ~!~~!~
. mQunting . . . fin ished in high temperature ;:
baked modern beige enamel.
net
' POWER RATING 15, walts continuous
$34.50
FREQ. RESP. 140·15,000 cps
0
IMPEDANCE 8 ohms. DISPERSION 120
'DIMENSIONS bell opening 15", overall depth 12"
• See the WT-6 a t your local distributor. Send for catalog , ;":"-,
ATLAS SOUND CORP.
1449 39th St., Brooklyn 18, N. Y.
" :~
.. ,
lI1
.~
THE OUESTION: Do you know where you can find information about
the current articles in magazines about microwaves, loudspeakers, television
repairing, electronic musical instruments, traveling-wave tubes, transistor
amplifiers, oscilloscopes, or any other electronic subject?
THE ANSWER:
EmoDEX
FORMERLY
MDIOFllE
Not a new publication, but one which for ove r ten years has served engineers,
libraries, experimenters, researchers, hobbyists, radio amateurs, radio and TV
repairmen, and anyone else connected with radio or electronics. Covers radio,
television, electronics, and related subjects, and published bi-monthly as a
cumulative index throughout the year, with the last issue of the year an
Annual wh ich may be kept as a permanent record of all electronic periodical
literature.
LECTRODEX-the electronic magazine index-has been expanded to include over twenty publications in the radio and electronics fields. Sold by
subscription only, $3.00 for one year, $5.50 for two years. Back Annual
issues are available for the years 1947, 1948, 1949, 1951 , 1952, 1953,
1954, 1955 and 1956 at 50¢ per Annual. Orde r your subscription and
Annuals TODAY! ! !
RADIO MACAZINES, INC.
P. O. Box 629,
Mineola, N. Y.
recommended load resistance (for example,
16 ohms).
8.02 Performance Tests
Since it is not within the scope of this
Standard to test all the characteristics of
the audio amplifier circuits, these tests will
not be covered in this Standard. For tests
on audio amplifier circuits, reference is
lI).ade to the appropriate IHFM Stanll:nd.
All the tests described in Sections 6.00
and 7.00 are to be made on AM/ FM tuners.
Because of the added complexity of AMI
FM tuners, some additional te~ts ha ve to
be made.
8.02.01 Cross-Talk
With the tuner connected for the r eception of frequency-modulated signals,
the tuner is connected to a signal generator equipped with the 300-ohm dummy antenna. The signal generator shall be frequency modulated with standard test mod ulation and be tuned to a mean carrier
frequency. The signal generator output
shall be adjusted 20 db higher than required for 30 db usable sensitivity. The
signal generator modnlation shall then be
switched off.
Without touching the tuning controls
of the tuner the tuner shall now be switched
for the reception of amplitude-modulated
signals and an AM signal generator modulated with standard test modulation shall
be adjusted in frequency so that maximum
audio output is obtained with the weakest
possible input signal. The output voltage
of the AM signal generator shall now be
adj usted to 100,000 microvolts. The tuner
is now switched back for reception of frequency modulated signals and the total
audio output is recorded. Then the FM
signal generator is modulated with standard test modulation and the audio output
is recorded again. The ratio of the two ontput voltages is called the AM-to-FM crosstalk ratio and shall be expressed in de<;ibels.
By a similar procedure the FM-to- AM
cross-talk ratio may be measured except
that the signal generator output shall b e
20 db higher than required for 20 db usable
AM sensitivity.
. ~f the tuner is equipped with audio
CIrCUIts for the reproduction of recorded
signals, the FM-to-Phono cross-talk ratio
or the AM-to-Phono cross-talk ratio or similar ratios may be measnred by a similar
procedure.
JE
AUDIO ETC
(fl'om page 46 )
automatically with the main ON -m'F switch
for yem's at a time without any att ention,
(2) The battery itself-the main bulkis small and compact, taking up much less
space than the flashlight cells in the other
system- and in terms of its hugely long
operating life, it actually costs less.
(3 ) It gives the better warning light
and, indeed, is one of the most effective
pilot lights of any sort.
(4) An odd extra value, at least in our
conversion, is that the neon lamp is visible
over a much wid er angle of view than the
incandescent, and so offers more protection-its first duty.
(The neon light is a thin "finger" almost
a quarter-inch long from front to real' of
the bulb. The incandescent filam ent is
much shorter and is placed well back in its
bulb; from the side, it is hidden by the
front panel surface of the preamp.)
Now I can well imagine that the professionals in this manufacturing area will be
shaking their heads at all this. They'll
point to costs, to the necessity of selling
hi-fi at reasonable prices and to the mark-
AUDIO
www.americanradiohistory.com
AmericanRadioHistory.Com
•
JUNE, 1959
up aspec t that exaggerates th e small first
cost of such a feature into a big extra
price rise at the consumer level. And, I
expect, they'll bring out their fin al argument, that the consumer doesn't want this
kind of extra gadgetry-or not at extra
cost .
I can answer such ques tionings by suggesting, first, th at the makers don't know
how the consumer feels, or would f eel ( es ·
pecially after a f ew dead batteries) with
a bit of straightforward selling as to th e
clear value of a positive pilot light. If l)(l
thinks it's worth it, he'll pay the price all
right, even up to four or five doll ars extra
in a piece of quality equipment such as
the Regency preamplifier. The pilot light,
rememb er, removes th e biggest disadvantage of the battery-oper ated component,
leaving its compactness and oth er virtues
intact. This applies to any sort of b attery
equipment you can name--excepting only
the subminiature transistor radios, where
there isn' t enough space, and low-priced
units where mark eting won't allow even
f or such a basic ex tra .
(Franldy, if a unit were so "cheap" as
to preclude nse of a pilot light, I wouldn't
buy it anyhow, myself.)
As for Regency, it's possible that the
HFT-IA might be offered with a nd without the pilot light, on a trial basis. Good
salesmanship co uld shoot some r eally hot
arguments to the consumer in favor of th e
pilot-light model, at a higher price. Isu't
advertising always t alking of its educational duty~ Well-here's your cha nce to
educate, boys !
"Anybody ever see an 'ordinary' preamplifier without a pilo t li.ght ~" That's what
competition will say, wh en somebody
jumps the gun a nd comes out with my
pilot-lighted ba ttery model-which is
bereby offer ed for free, by self and
Prohaska, to all who maybe want to try.
( We didn't bother to find whetber we
wer e the fir st and I dea rly hop e th at somebody like RCA doesn 't asl, me for a licence
f ee.) H elp yourself!
1E
PA R'l'S L I S'I' FOR R EGENCY PILO'I' LIGH'l' S
A. Neon flasher
New p o t e ntiom e t e r ...
.93
DPS'l' s witc h t o fit
.44
NE 51 Neo n lamp
.I S
67 'h vo lt ba tte r y
(Burgess UX45 : R CA VS-I S
2.07
Capac itor 0.1 f,f a t 200 v.
.21
R e sisto r 47k, 'h w .
.10
Audiofan net cost: $3 .93
(Soc k et fo r bulb, if u se d, in a d d ition.)
B. Incandesce·n t continuous
N e w p o t e ntiom e t e r (as a b ove )
.93
DPS'l' s witc h to fit (as a b ove )
.44
GE 4 9 low-drain la mp
.I S
R esisto r 1 5 o hm s, 'h w.
. 10 (?)
2 "C" fl as hligh t ce lls
. 30
2 "C" c lip s
.60
Audiofa n net cost: $2. 55
(B ulb sock e t n o t in c lud e d )
AUDIOCLINIC
(11'01/1
page 4)
DVNAKITS
\
Look Best - Test Best - Sound Best
NEW
STEREO 70
KIT
* Dual
35 watt super-quality
Amplifiers-70 watt continuous monophonic rating- 160
watt p eak
* cated
All critical parts on prefabri printed circuit assembly
reduces wiring time to five
hours
* servatively
Premium quality parts conoperated permit
one year gua ra ntee
* Uncompromised
design for
fi;'1est performance - usable
with all speakers
* parts,
Only $99.95·:':- net including all
instructions, and protective cover
Step up to STEREO
Superb Dynakit Quality Is Fully Compatible With Stereo Requirements
* Famous
D ynakit Preamplifiersdistortionless and noise free s tack harmonious ly for stereo .
$34.95* each
* Add
DSC-l Adaptor unit for comp lete fl exibility. Includes blend,
balance, du al volum e con trols plus
·loudness, tape monitor, and reversing switches. Useable with
most high qu ality preamplifiers.
Only $12.95" net.
* integrated
PM-2S Panel mount kit provides
handsome appearance
plus mounting faci lity- $5.95 net.
ous problems. Two separate one-quarter
t r ack erase heads ar e necessary. Each of
these mu st be so precisely oriented and
connected to switches in such a manner
that on ly one t rack at a time will be
erased.
This scheme r eg uires a t ape transport
mechanism capable of holding four heads.
Mechanical and electrical details for this
project will be determined by the type of
mechanism a nd by th e type of heads employed.
IE
AUDIO
•
* CM-2S
Cabinet Set includes
front panel and walnut table top
cabinet.
$17.95* net.
Available from leading Hi-Fi dealers everywhere.
D escriptive brochure ava ilab le on r eques t.
* Slightly higher in West
DYNACO INC.
617 N. 41st St., Phila. 4, Po., U.S.A.
73
JUNE, 1959
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AmericanRadioHistory.Com
TRIMENSIONAL SPEAKER SYSTEM
(fr om p age 23 )
above are adjusted to obtain tonal balance.
Some examples of use in difficult locations ar e shown in Fig . 11. It will be
noted that this sp eaker ystem need n ot
be in the center of the wall. It can also
be used in a corner.
When the Trimensional speaker is used
f or monophonic r eproducti on, identical signals ar c fe d to the two sp eaker
systems, and the doors ar e usually f olded
across the f r ont of the cabinet to r educe the directional characteristics of
the side sp eakers, helping create the
impression of a single source. However ,
when listening to progr am material that
is normally spr ead out rather than concentra ted, such as symphony or chestra s,
choruses and the like, the doors are best
left op en, in the usual stereo position.
The r e ulting spreading out of the sound
is similar to the effect obtained with
multi- p eaker systems spaced along th e
wall, and contributes greatly to r ealism .
During the design of the Tr imensional
sp ea kCl·, consider able concern was fe lt
for conect phasing, because of the combination in oue woofer of both bass
channels. Term inals were car efully
coded to insure correct phasing a t all
times. Experiments to evaluate the eff ects of incorrect phasing wer e conducted.
With monophonic reproduction, things
we nt exactly as expected. W ith t he
woofer voice coils in r everse phase, most
of the bass disappear ed, being bucked
out in the sp eaker electromagnetic stru ctur e. With ster eo, however, r eversing
one voice coil had n o audible effect r
Measurements in a live listening r Oom
indicated a possible loss due to incorrect
phasing of 1-2 db only, confirming the
auditory r esults.
Further study yielded the exp lanation. W hen clo ely sp aced for s ter eo
pickup, both microphones receive signals in the bass range th a t ar e virtually
identical in level and phase. If such signals ar e combin ed in r ever se phase, t hey
cancel out. H owever , the ster eo r eading
techniques gener ally in current use utilize microphones sp aced a consid erable
distance apart. The combination of wide
spacing with the effects of r everber a tion
in th e hall or r ecording studio causes
the varia tion in phase of the signals
reaching the microphones to be es. ~ n­
tially r a ndom . Under these conditions,
combining the signals "out of pba e"
makes ver y little differ ence both theor etically and in practice. Ther e are two
exceptions to this condition : r ecord ings
in which a center channel i electri cally
mixed equally into th e two r ecord ed
channels- and r ecordings made by the
"M-sm system. For this r eason, it is
a good idea to make sure t hat amplifiers
and pickup ar e properly phased. As
stated befor e, the speaker terminal are
coded. The simplest test is to play a
monophonic r ecord using a ster eo
p ickup. Reversing the phase of one
channel will cause the bass to decrease
or in crease noticeably. Correct phasing
is indicated by the gr eater a moun t of
b UL
E
2 E.M.I. SteTeosoni c system.
TAPE PREAMP
(f?"Om page 20 )
tube sockets as pos ible. T f is fixed to switch, to stop t.he motor s. Between 20
the shield, and t his is then riveted into and 30 ma are r equired to energize the
p lace. All ground r eturns ar e insulated, coil , and the 10,000-ohm r esistor is conand terminate at the co-ax shells, apart nected from G to F on th e terminal
from Gr, and all tube socket pigots al·e strip, E being joined to ground.
The power cable-f orm is attached to
included in the grollild loops. The slider
of P 4 is joined to the output co-ax its supply, after attaching a shielded cospigot, and the r est of the wiring is axial lead between the replay output
completed. F igu?·e 9 shows the under - socket and main ampliller input, and the
neath of the finished amplifier , wit.h F ig . the r ep lay section of the TW IPA2 is
10 showing the parts p lacement.
tested first, by tuming the gain controls
Af ter checkin g and r e,-checking the 011 both r ep lay and main power-ampliwiring a nd connections, ·a nd winkling fi ers to maximum , and noting wbetber
out th e odd bits of solder th at have col- motorboa ting occurs. If it does, the cause
lected between the tube socket terminals, is almost certainly the connection of
the tubes and various p lugs may noW be R 0) R 21 and so on to th e junction of R .
inserted, and testing carried out; but note and R 7 instead of R . and R s. (A nearly
that fmal p r ep arations include the pro- all my own wiremen do it th e first ti me
vision of a 10,000-ohm, l5-watt resistor they make these amplifier s, ther e is no
for operating the "hold-in" solenoid on need f or the amateur to blush!) H avthe deck . This is a neat little device f or ing made th e necessary corrections, if
holding in the switches and linkages, and r equired, t he chassis base is scr ewed
it provides a quick-release mechanism, into posit;on, and noise and so on noted.
by means of a pushbutton and micro- I nclu ding the main amplifier, which is
74
AUDIO
www.americanradiohistory.com
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•
JUNE, 1959
marantz
did it
(:)
BIAS TRA P
Cillj
R20[-----~
C3
r.;;;:;,
- - - - - L-J L.!l1ZJ
·lcla
I R22
UNDER
(: :::::J
c::::JR23
R2l
I
I
I
,IIIillrillolz ::::::7)~~')- .«:on§ole
I
I
With th e introduction of its new model 7 Stereo
Console, Marantz Company ha s once more
made it quite clear
it inte nd s to maintain
leadership in top q uality components . Nationw id e reports show that this sup er b stereo control is alread y recognized as be ing entirely in
a closs by itself.
Fig . 10. Ports placement diagram .
assumed to be above suspicion, it should
be at least 80 db down , or , f rom the
home-constructors'
viewpoint,
ther e
should be little or no background at all
when playing at maximum power output
from a fully modulated tape. The r est of
the work on this section is easy, consisting of playing a known good tape and
listening to what it sounds like. If it
sounds good, all is in order . (It must be
confessed, however , that the f actory
procedme is a little more elaborate.)
Now we come to the recording amplifier . The base i r emoved, and a VTVM
and 'scope are connected between the
junction of G10) R 12 and ground, with
the deck switch in the replay position;
and a low-level-below 2 mv-sine-wave
signal at 1000 cps is fe d into the LOW
input socket. P 1 is advanced until the
VTVM shows between 30 and 35 volts,
whil e the wavefor m is checked on the
scope. It must be of good shape, and if it
is, the operator may r est assured th at,
at the maximum r ecording signal level
of 23 volts, distortion will be negligible.
(There is sometimes sharp clipping on
either the top 01' bottom p eaks, and if
this occurs, susp ect the VTVM. R emoval
of the probe will show whether the
VTVM input circuit is responsible.) · Increase the gain until the p attel'll squares
at top and bottom, when the meter indication will, after reaching a maximum,
drop. If an r .f . trace appears, p articularl y on the rising edge, it is due to the
proximity of the lead f rom th e slider of
P, to the connection from R 7 to the
socket pin. Moving this latter away will
cure the trouble, as little as 1,4 in. being
all that is necessary. If ther e is still
some residual r.f., a capacitor of 25 !-tllf
between anode and grid of V 1 will clear
it up quite r eadily .
AUDIO
•
Switch the deck to RECORD, tUl'll P 3 to
its minimum position, and adjust P 1
until the VTVM shows 23 volts. Adjust
P 2 so that tbe modulat ion meter needle
r eaches 0.75 f ull scale. This is the maximum modulation p oint, and must not be
exceeded, except only on the very heaviest p eaks. Remove the input signal, connect the scop e between the junction of
G 13 and P j)) advan ce P 8 until the valve
oscillates, and then adjust the f r equency
of oscillation to 50 kc by means of the
core of Tl and comparison with a 50 kc
disp lay previously shown on the scop e
via the signal generator. This is simpler
than the laboratory method, and is sufficiently accurate f or most purposes. Advance P s until the trace deteriorates, and
r e-adjust to the maximum level p ermitting good shap e. Transf er the VTVM
probe to the junction of R l l and L l ) adjust L 1 core f or 'lnini'ln~£'In indication on
the meter , and then take the probe to
terminal 2 under the deck, wher e the indication should be 32-42 volts. Termin al
3 is the next p oint, and P 5 is adjusted to
the r ecommended bias- usually between
11 and 13 volts- after which P a slider
position and the oscillator wavef orm
are again checked, while the voltage at
termin al 3 is remeasured and, if necessary, r eset. The modulation meter is
looked at, and if the needle shows a displacement f r om th e zero position with n o
signal, R 15 is alter ed until a stable zero
is found. If th e displacement is positive,
decr ease R 15; if negative, incr ease it:
but make the alter ation a little at a time.
Recheck for maximum modulation p osition, fix the bottom on the chassis, mak('
a test tap e or two, and the TW IPA2 is
r eady f or incorporation in yom set-up.
(But don't forget, if you have a 2B
three-head deck, to join the shielding 011
th e r ep lay head lead to the shielding on
A glance backward confirms the consistent
lead e rs hip of Marantz producls :
*
*
In 1954 - Marantz e ntered the high
fidelity field wi th its famous " Audio
Con so lette", still acknowledged to be the
finesl monopho nic preamplifier.
In 1956 - Introduction of th e Marantz
40 wa tt mod e l 2 amplifier and, more
recentl y, the lemarkable 30 watt mod el 5,
changed all previous conceptions of
performance and power re quirements.
Both model s consistently outperform
amplifiers of consid erably higher ratin g.
The model 5 wi ll drive low·efficiency
loudspeakers w ithout breakup whe re most
*
others foil.
Now . .. the Stereo Con sole has set a new
pe rformance level for preamplifi e rs . It
introduces a new order of freedom from
d is to rtion, hum , and noise . Straightforward
and easy to use, the high est o btainabl e
res ults are you rs . . . effor tlessly . .. an d
with a ce rtainty that can be found onl y
in on inst rumen t as well co nceived a s
the Ma rantz Stereo Conso le.
For a · superior stereo system:
STEREO CONSOLE model 7 .............. $249
30 Watt AMPLIFIER model 5, each .. 147
•
~
____ •
highe
r in
West
_ _ _ • • _ _ slightly
___ _ _
___
w _
___
I
Rltill rilln Iz «CORlt pillny
25.14 Broadway, long Island City 6, N. Y.
75
JUNE, 1959
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I
~
IMPORTANT
Bound Volume of AUDIO Maga%ine
ANNOUNCEMENT
January-December 1957
A full year of AUDIO durably preserved in a handsome binding for
quick, easy reference at all times. Onl,), a limited numb eT available-so,
be sure to order your copy now!
No. 122 195 7 Bound Volume of AUDIO $10 Postpaid.
SHIPPED SAME DAY WE RECEIVE O RDER !
(U. S. DELIVERY ONLY)
No. 110
HANDBOOK OF SOUND REPRODUCTION
by Edgar M . Villchur
Right up to date, a complete course on sound reproduction.
Covers everything from the basic elements to individual
chapters of each of the important components of a high fidelity
system. $6.50 Postpaid.
NEW!
No. 120
THE 4t h AUDIO ANTHOLOGY
$2.95 Postpaid
No.112
This is the biggest Aud io ' Anthology ever!
Contains a wealt h of essential high fidelity
know-how in 144 p'ges of complete articles by world-famous authors.
TAPE RECORDERS AND TAPE RECORDING
by H arold D. Weiler
A complete book on home recording by the author of
High Fidelity Simplified. E asy to read and learn the
techniques required fo r professional results with home
recorders. Covers room acoustics, microphone techniques, sound effects, editing :jnd ~licing, etc. Invalu-'
~ble to recording ent!J.usiasts..
.. . Paper Cover $2 .95 Postpaid.
No. 115
McPROUD HIGH FIDELITY OMNIBOOK
Prepared and edited by C . G . McProud ,
publisher of Audio and noted authority
and pioneer in the field of high fidelity.
Contains ·a wealth of ideas, how to's,
what to's and when to's, written so
plainly that both engineer and layman
can appreciate its valuable context.
Covers planning, problems with decoration, cabinets and building hi-fi furn iture. A perfect guide. $2.50 Postpaid . .
NEW!
No . 119
HIGH FIDELITY AND THE MUSIC LOVER
by Edward Tatnall Canby
An up-to-the-minute guide that shows you how to get t he
best out of your hi-fi records and tape recorder. Mr. Canby
discusses in detail the speaker, the amplifier, the radio tuner,
the record player and the tape recorder. He shows you how
to save time and money, and get the hi-fi equipment that suits
yo ur parricular needs. Illustrated with line drawings. $4.9 5
No . 118
NEW ! Ho w-to Book on Hi-Fi Repair
CARE AND REPAIR OF HI - FI-Volume
by Leonard Feldman
AUDIO Bookshelf
Latest information on hi -fi components for efficient repair and n13intenance. Complete, down-to-earth information that is not punc-
RADIO MAGAZINES, INC., Dept. A
P.O. Box 629, Mineola, New York
Please send me the books I have circled below. I am enclosing the
full remittance of $............................. . (No . C .O.D. )
tuated with complicated mathematics. Helpful to the hi-fi enthusiast
technician or engineer , t h is first vol u me includes many importa n
feat ures: Example schematics with tube by ours, descriptive illustra·
tions and hook up diag rams, buyers' guide. 15 6 pages pro/usel)
illustrated. $2.50 Postpaid.
All U.S.A. and CANADIAN orders shipped postpaid. A dd 50¢ for Foreign orders
( sent at buyer's risk) .
BOOKS:
110,
112,
115,
118,
119,
120,
122
NAME _______________________________________________________________
ADDRESS,___________________________________________________________
.CITY____~~_____________________ ZONE _STATE _________________
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for
RECORD'
100 K
PLA Y 0
LOWEST
microphonics .. .
hum ... noise .. .
in a high-gain
dual triode:
the
AlTlperex®
ECCBa
APLUG·IN
REPLACEMENT
FOR THE 12AX7
Fig. 11 . Modifications fo r high-impedance he ads .
the record head lead. This lead, incidentally, will not be used).
Generally speaking, there is nothing
to prevent the eonstructor making alterations to the circuit, as it is quite
tolerant in regard to resistors and capacitors and, to some degree, layout. It is
unlikel y that p erformance will be improved, but as interest will be stimulated, experimentation is not to be discOUl·aged. There is, however, one direction in which alteration is bound to
have an adverse effect. Be warned! Do
not try substitutes for the specified tubes.
They have been chosen only after 11
great deal of test and development, and
the slight differences present in apparently similar types ar e sufficient to degr ade the performance of the amplifier,
which is quite a high-efficiency piece of
apparatus. This warning applies pal·ticularly to V 1 ) V s ) and V 6 ) the EF86, for
which, in my opinion, there is no alternative with t.he same consistency in
respect of freedom from hum and microphony.
ApPEN DIX
To use th e P A2 with decks fitted with
high-impedance heads, and without integral
switching, th e following alter ations from
the original circuit must be m ade. In F ig .
11, tube numbers and components are a s in
Fig. 1, but the deck r ef erences and coding
are ignored. 8 1, 8 , is a two-pole two-way
Mallory-typ e switch, and th e connections
are made as shown. The output from th e
anode of 77" , goes, via th e equalizing network, to Oll e contact on 8 " whil e the control
grid of 77." which is tied t o ground by a
470k leak, is joined to th e oth er contact.
Th e moving member is connected to th e
r ecord-replay head. Only one contact of 8 ,
is used, and this is joined to th e point
m ark ed (4 ) in F ig . 1. Bias and er ase, instead of being drawn from the secondary
of T" are t al,en instead f rom t he anode of
77, through CA and CI/, adju stm ent for opt imum bias being by way of th e potentiomet er P , the slieler of which is left in
permanent connection t o L 1 • and so on. In
the REC ORD position, 17,,\ anoel e is conn ect ed,
vi a the eqn alizing network, to the r ecordr eplay head, while V, is energized by connection of th e oscillator section to th e B+
line. In th e RE PLAY position, t he r ecord
head outpu t goes to th e control grid of 77,.
Wi th three-h ead decks, 8 , is omitted, th e
connections to the appl'Opriate heads b eing
p ermanent.
For th e TW I PA2, mo st of th e pa r ts will
be obtainable f rom neighborhood jobber s,
but certain of them can be ha(l only f rom
Ercon a Corporation , 16 W est 46th St., New
York 36, N . Y . These ar e :
The deck , the F errograph typ e 2A or 2B
T th e oscillator coil, Wright & Weail'e
"t yp e 579
T " th e tape-head input transformer ,
Wright & Weaire type 977
L J> the bias-trap coil, Wright & W eairc
t ype 666.
The m et er is a Sifam t ype M202, 1 ma
full- scale deflection, and t his t ype and
make should be used i f possible, as its b allistics are p erfect for monitoring.
Th e r ecommended potentiom et ers ar e
Clarost at type 37.
Suggested f or th e output transformer i s
Stan coI' A3877 , and f or t he power tr ansformer, StancoI' P C8403.
MICROPHONICS:
Negligible in amplifiers requ i ring an
input voltage of at least 50 mv f or
an output of 5 watts.
HUM AND NOISE LEVEL: '
Better than - 60 db relative to 50 mv
when the grid circuit impedance is
no greater than 0.5 megohms (at 60
cps) . the center t ap of the heater
is grounded and the cathode resistor
is by' passed by a capacitor of at
least 100 mfd.
Ask you, Ampe,ex disl,ibulo, aboul Ampe,ex vollage
amplifier, rectifier and output tubes for hi..1i Circuits
Arnperex
ELECTRONIC CORP.
230 Duffy Avenue
Hicksville, L. I ., N. Y .
Circle 77 A
•
Soundcraft's MAGNA-SEE Kit lets you
see the sound on your tape
H ead Alignment • H ead
wea1' • T1'ack placement and balance
Checks for: •
Contains : 1h pint
Magna-See Solution
• Plastic bath
• E ye-piece magnifier
• Pressure-sensitive
tape • 5 glass slides
for permanent copies
of your developed
track, and complete
instructions.
(A)
For free MAGNA,SEE
brochure, write
REEVES
Mak es editing easior
.. . m01·e exact.
SOUNDCRAFTcORP.
GREAT PASTURE ROAD, DANBURY, CONNECTICUT
Fig. 12 . Two types of mixer circuits.
AUDIO
•
West Coast: 342 N. La Brea., Los Angeles 36, Calif.
Canada: 700 Weston Road, Toronto 9, Ont. Canada
Circle 77B
77
JUNE, 1959
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what's so special about
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"PROFESS ION AL"
IOQK
VITA VOX?
Rates: lO¢ per word per Inmtlon for noncomm",ial
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allowed. COpy must be accompanl.d by r. mlttan.. In
full, and must reach the New York om.. by the
first of the month preceding th e date of Issue.
300~ fJI
Made in Eng/aTld
by Vi!auox, Ltd.
'ADJUST ON TEST
Sound craftsmanship! In a
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and competition by price
there is, for tun a tely, still
room for the individually
craftsman-made
assembled
product. In the fi eld of
so und reproduction, Vitavox loudspeakers are renowned for j ust these characteristics a nd are prized
b y th e purchaser who
places qu ality of p erformance a nd construction above
other considerations. The
DU120 Duplex Coaxial Full
R a nge Loudspeaker is a fin e
example of mod ern a ud io
Fig . 13. Equalizer used in "professional"
models .
Modifications
Suggestious ar e given below f or one or
two possible modification s to the circuit, to
en a ble ad apta tion for custom purposes.
(A ) and (B ) of Fig . 12 p ermits of mixing two sources, while F 'i gs. 13 a nd 14 give
usefnl means of I'eplay equali za tion, F i g.
13 in p a rticular allowing very sharp p eaking at any select ed frequ ency, for use with
restrict ed r a nge recorded tapes. The formula a nd details will b e f onnd in the Novembe r, 1957, issue of AUDIO, but damping
of th e network b y a r esistor- 2. 2 megohms
in drawing-selected according to requireme nts, m a y b e necessary .
lE
"H I-F I"
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A full range of Vitauox slJeakers are auailable to
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ERCONA CORPORATION
Circle 78A
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82 ~~f
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PORTABLE FIELD RECORDER
Cllec/t Tllese IInusuIII Fell/utes:
v Low noise input stage (0.25 microvolts).
v Overall Gain 110 db.
v No Microphonics or motor noises.
v Uses Dry Rechargeable batteries.
v Batteries last 125 hours.
v Modular plug-in construction.
v Exceeds NARTB Broadcast standards.
v Size: 11x 10 x7 inches-Weight: 15 Ibs.
v Full unconditional Two Year Guarantee.
HIGH FIDELITY SPEAKERS REPAIRED
Ampr ite Speake r Se t'vice
70 Vesey St., New York 7, N. Y. BA 7-2580
ENJOY PLEASANT SURPRISES? Then
write us before you purchase any ill-fi. You' ll
be glad you did. Unusual sav:ings. Key Elect ron ics, 120 Liberty St., New York 6, N. Y.
EVergreen 4-6071.
WRITE fo r confidential money-saving prices
on your H i-F idelity amplifiers, tuners, speakers, tape recorders. Individual quotations
only; uo catalogs. Classified Hi-Fi Exchange,
AR, 2375 E. 65th St., Brooklyn 34, N. Y.
INDUCTORS fo r crossover network. ·. 118
types in stock. Send for hrochur e. C & M Co ils,
3016 Holmes Ave., N. W. , Huntsville, Ala.
UNUSUAL VALUES. Hi-Fi components,
ta pes a nd tape recorders. Send for package
quotat ions. Stereo Center, 18 W. 37th St.,
N. Y. C.
c raft~mans hip.
(Electronic Division )
16 W. 46 St., D ept. 36, New York 36, N .Y.
TRADE UP TO STEREO: Large t selection
of new, used Hi-Fi components. Professional
service faciliti es available. Write Andio Exchange, Dept. AEI for trading information.
153-21 H ills ide Ave., Jamaica 32, N. Y.
Branches in Brool;!yn, 'Vhite Plains, Manhasset.
Fig . 14. Equalizer used in " hi -fi " models
with h igh-impedance heads.
JBL
becomes
MOSBY
'l'he title of " Most Outstanding Busines
of th e Year" was best owed upon James B.
Lan sing Sound, Inc., b y the N a tional Convention of A ccounta nts a t th eir 12th Annu al Southerll California Business Show a t
th e Ambassa dor Hotel in April. T his awa rd
is given a nnu ally by th e orga niza tion a nd
is signified b y a pl aqu e presented to the
president of the chosen company. The photo
shows William H. Thomas, center , receiving
the plaqu e from H a rry Ramph, past president of the National Association of A ccounta nts, with Edmundo Gon zales, M exica n Consul General, at th e left.
Mr. T homas, ill receiviJlg th e a ward for
ltis compa ny, was himself cited as " Outst a nding Business Ma u of th e Y ear."
Eyery one in t he indu stry is pleased, not
. only for JBL . b ut th a t on e of it organiza tion is singled out f or this honoI'.
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CONCERTONE 29-8 stereo pla yback. 3
Mabogbany cabinets with 2 each preamplifiers,
amp lifiers, and s peakers. Excellent condi tion,
only $650. Tom Waters, 65 Gage Street, Kingston, N. Y.
WE WILL NOT BE Ul\TJ)E RSOLD ! We
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SELL: E lectr o-Voice Georgian speaker system- perfect conditiou. Raymond Bindel', 1977
Powell Ave., New Yorl, 72, N. Y.
CLEANING HOUSE : B rowning RJ-20A ,
AM-FM, $45; Radio Cra ft sma n RC-8, $25;
Heathldt BC-1, U5; Wi lliam son Amplifier,
4-5881's, LS output, $45; Altec 603B, 15"
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RECORDS, masters, pressings. aud tapes
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s peed tape dupli cating.) Quantity discounts,
specialized services. Write--Merl e Enterprises,
Box 145, Lombard , Illi nois.
SHOP FIRST, then compa re our unbeatable
low prices. L 'n" J H igh F idelity, 416 N. 15th
St., Kenilworth, N. J.
WILL PAY $30 pIn s hipping for Mclnto h
C-4 preamp, serial #6600 or later, with cable
and cabinet. John Ayres, J ermyn, Pa.
HI-1~ I SALESMAN wan ted to merchandi se,
capabl e of t a king advantage un limited oppo r t unity, N. Subu rban Phila. Box CF-1.
Audi o.
SOUND BUSINESS FOR SALE
Equipment, trucks, all contracts-no
competition. Distributor for major
lines. Owner retiring_
Quality Sound Service
Write for complete information and
direct factory prices to Dept. A:
AMPLIFIER CORP. of AMERICA
298 Broadway. N . Y. 13. N. Y.
'T.'"
1217 N. Wilson Way
Stockton, Ca lif_
Circle 788
78
AUDIO
www.americanradiohistory.com
AmericanRadioHistory.Com
•
JUNE, 1959
PROFESSIONAL
DIRECTOR Y
the more you know about hi·fi
... the more you'll enjoy it
RIDER HI·FI LIBRARY
FU NDAMENTALS OF HIGH FIDELITY by H erman
Burstein. H ow to select t he best h i· fi
equ ipment for t h e mon ey you h ave to
spend-how to achieve t he best per form.
ance a n d reali ze t he most p leasure from
YOTJr eq ui p ment. #2 26, $2 .95
STEREOPHONIC SOUND b1l Norman H. CrowhUTst. Saves you hundreds of dollars in
selecting your stereo system, #2 09, $2 .25
HIGH FIDELITY SIMPLIFIED (3rd Edition) b1l
H arold D . Weiler. Answers all questio ns
about tuners , changers, a mplifi er s , tape
recorders, speakers, etc ., #142, $2.50
REPAIRING HI-FI SYSTEMS by David F idelman. S ave money ! Deals with fi nd ing a n d
repairing t.he troubles . #205, $3.90 .
HI-FI LOUDSPEAKERS & ENCLOSURES b1lllbruAnswe rs a ll Qu es t ion s on
loudspeakers and enclos ures, des ig n , cross.
over n e twOI"ks, etc.. # 176 Ma r'co covel',
hU1n B. Cohen.
$4.60 ; # 176-H cloth bound . $5 .50
GU IDE TO AUD 10 REPRODUCTION b1l David
F'idcl'm.Cln. Cove rs des ig n . assembly a n d testing of sou nd reproduc t ion sys te ms and
compon ents, # 148, $3.50
HOW TO SELECT & USE YOUR TAPE RECORDER
by D. Marie. S aves mo n ey for ta~e r ecorder
users a nd prospective buyers. #1 79,
at bookstores,
-.~
.
. 1.:\.,:
$2 .95
m·de?· di1·ect: A-4
01·
JOHN F. RIDER Publisher, Inc.
~';J116 West 14th Street, N. Y. II, N, Y.
Circle 79C
special
recording tape
$1.19
1200 f t . ; 7 " - g uaranteed splice-free
18 00 ft. ; 7 " •.• $ 1.89. Enclose 1o ¢ for
e ach re e l to cove r postage and handlin g.
Circle 790
Get more FM stations with the world's most
powerful FM Vagi Antenna systems.
Send 25; fo r book l et " Them, And V,arla·
ti ons" containin g F M Stat ion Di rect ory.
APPARATUS DEVELOPMENT CO,
Wethersfield 9, Connecticut
C:rcl 2 7 9 E
1~ hoied. •• •
TOURING STEREO SHOW. Bogen.
P resto COlIlll a ny i s pa rti c ipatin g in th e
fir st llatlOn -wlde pack age d m u sic a nd
f"s hi o n s h ow "ITa n ged a nd prese nte d by
Ho li day m agazllle . Th e s h ow is sc h e dule d
in m a j o r c ities t hrou gh Jun e. A comp lete
B oge n ste r eo hi-fi music a nd p ubli c add r ess syste m is b e ing u se d in a spec ia ll y -co n s tructed tra ile r wh ic h is the
stage for 93 indi vidua l per fo rma n ces, in
d e p a rtm e n t stores, h otels a nd local TV
sta.t i o n s : In a ddition t o Bogen a mplifiers,
Uruverslty lo uds p eak ers a l·e u se d t o com p lete t h e in stall a ti on.
IHFM
FORMS
PUBLICATIONS
GROUP. Jo seph Be nj a min, preside nt of
t h e I n s t itu t e of Hig h Fidelity M a nufa c.
turel·s , h as a nn o un ce d format io n of a publica ti ons co mmi ttee to ass is t t h e I n s tit u te
in pro m oti n g hi-fi comp o n e nts . In all n o u n c in g t h e g r o up Mr. Be n ja min said it
··wi li a dvi se the IHFM o n techn ical m atters, trade a lld 11le rch a ndi s in g prac tices,
lll et h o cls of con vey in g t h e cOlllp on e n t story
to t h e pub l ic, a nd o the r time ly s ubj ec:ts.
C. G. McPro ud, e di tor a nd p u b li sher of
AUDIO, wi ll h ead t h e group, with t h e r e m a ind e r m a d e up of r e pl·eselltatives of
ot h el- publi cations covering t h e compon e nts industr y.
NAMM STEREO SALES CLINIC. L. M .
San dwi ck, v i ce-pres ide nt in c h a r ge of
sales, Pilot R a dio Corpora,tion, will b e t h e
fir s t s pea k e r a t a s p ecia l stereo -hi-fi sales
c lini c to be co ndu c t e d ill co nnection with
t h e a nnua l t r a d e s h ow of t h e N a tiona l
A " socia-tion of Music Merchant s . The c lini c
i s sc h ed u le d for Junl~ 24 at 9 :30 a .m. in
the Hote l New Yorker . Oth er p a rtic ipa nts
in the c linic will b e Wi lliam A. Fink,
sa les manager of professi onal prod u cts,
ORRa dio Indust,r ies , Irv jn g
Ro ss mall,
p r es id e n t, Pentron Corp ora tion, a nd a
f o urth spea l<er yet t o be a nno un ced. R ulon
A. Os tle r, c h a irm a n of t h e NAMM e lectr on ics comm ittee, will b e c h a irm a n .
PICKERING LIFETIME WARRANTY.
Walter O. Stanton, p r esident of Pickering
& Compa ny, a nn o u n ces t h a t the Sta nton
M o d e l 371-.7 D stereo F lu xval ve car t ridge
a nd t h e Model 196 U nipoise arm with
in tegTate d p i ckup n ow ca rry a lifetim e
w a rraJlty. '·Becau se each Pickering pro du ct i s v ir t uall y hand- crafted and un dergoes t h e sam e rig id quali ty contro l standa rds t h at hav e es tablis h e d P ic k erin g as
a l ead er in th e fi e l d of hi g h fid e li ty for
ove r a d ecade, 'v e h ave in s titute d a wa !~ ­
r a nty wit h o u t t im e limit," Mr. Sta nton
said.
E-V SALES AND PROFITS JUMP. Inc r eases of 75 .7 per cen t in n e t profit s a nd
25.4 pe r cent in sales wer e reported by
Electro-Voic e', Inc., in its fis cal year
e nde d Febr ua ry 28, 19 59 . Both fi g u res a r e
r eco rde d hi g h s. The fi rst E-V public an nu a l r e p o rt s h o w s ll et profit at $620 ,51 9, or
$1.55 p e r share . Thi s co mpa r es with $353,188 , o r 90 ce nt s p e r s h a r e in t h e p r ece din g
fi scal year. Sales a m o unte d to $11,764, 676
co mpa r e d with $9 ,379,132. A lbert Kahn,
E-V preside n t, attributed t h e in c r ease itt
sal es and earnings la r gel y to the s hi p ment of stereo cartridges in t h e las t h a lf
of 1 958 . He r eporte d overwhelmin g accept a n ce of the n ew low-price d line of Wolve rin e h ig h-fid e li ty speak ers, a nd fore saw a s trong m a rket position for E lectr oVo ice in 1 959 .
CANADA
•
Complete Service
HI- FI Records - Components
and Accessories
&LE'CTRO~lJOICB
SOUND SYSTEMS
126 Du N DAS ST. WEST, TORONTO, CANADA
Circle 79F
AUDIO
•
Complele dala and price IIsl s
for Qualified respondenls
I
~
~
~!!S9v~t~RA-6. :'::'~'S
6 West 46th St., New York 36
Finest
AR GETS BRITISH PATENT. A British
pate n t on the aco u stic s u s pensio n system
for lo uds p eak e r s h a s b een gTante d Acous tic Research, Inc., m a n u fac ture r s of AR
s p eal<er systems. Th e n e w patent is valid
f o r G r eat B rita in, North e rn Ire la nd, a nd
the Isl e of Ma n, a nd exte nds the cove r age
provided by AR's U . S. pate n t. The compa n y n ow h as o n e lice n see a nd is u nderstood to be n ego tiating w it h oth er prosp ec ti ve li ce n sees.
Hilh Fidelity Equipment
Complete Lines
Fine sound reproduction begins with
a good microphone. Reslo microphones bring out the best in your
recorder with unsurpassed quality
fo r clean, silky, uncolored, flat res;, lnse to 20,000 ci s.
Quality recording, broadcast or P.A.
uses require a Reslo Mark III. Blastproof, fully shock mounted, triple
shielded for outdoor use, they can
be boom mounted without adaptors.
Exclusive ribbon permits near automatic self-service replacement.
Reslo microphones are used by leading broadcast and recording firms.
Try one at our expense . . . see your
dealer.
LO OK
no further • • • If yo.'r.
searchIng for hl-f lsav....
WrIte us your req.I ..•
ARKAY (S·28
STEREO AMP/PRE-AMP
(OMPLETE
(ONT1IOL (ENTER
F
watts stereo or monaural. 60 watt s peak . 14 watts ea cfl
chann el • reverse stereo • balance control • two·channel gaIn
ignlr~1 .har~~ni~a~rseto~t~ ~~,a~~o t~~~~,~~~trco~: J~ald~Sr~~~t~0:'2~
:
output Jacks • speaker outputs. 4, 8, 16, 32 ohm s • re sponse.
20·20.000 cp s • pu sh-pull ElB4 Wi ll ia mson cir cuit.
$
Wir ed and l es t ed $99.95
Easy·to-build Kit
64
95
ARKAY ST·ll AM-FM
STEREO TUNER
Here. for the first tim e, i s an AM·
FM STEREO Tuner with in the reach
of every audiophi le . Unmatched by
units costing twice the price , the
ST-1l is two distinct receiVers i n
one featuring 4 " V. for 20 db qU ieting. Vari able AFC . Singl e front
95
panel switch controls AM , FM or STEREO selection.
Wired and tested $74.50
Eas y·to -bu i ld Kit
•
$49
~
-
. ... , ",,-./,
~"a"k·
J ~ ,JJ
.
ARKAY SPA-55
STEREO AMP
Two 27 1/2 watt distortion·free
hi·11 amplifiers for st er eo. Or
use as 55 watt monaural am·
P~~I:;:IO.bUild
. .
~~:.._~~ )I
Kil$64 9 5
Wi red and t es ted $79 .95
ARKAY SP·6· STEREO
(ONTROL (ENTER
~~~ial~~eut~te::: :~fp~~l :i~~:
filters , reverse pos iti on, bal.
ance control. Less cover .
EasY.lo.build Kit$399 5
Wired and test ed $62.95
ARKAY Kits at your dealer.
and calal ag. Write Oept. A
ments n ow •. .
Key Electronics COIII....y
120-K LIHrty l t., N.Y. 6, N.Y.
EY 4-6071
Circl ~
79C
Circle 79B
79
JUNE, 1959
www.americanradiohistory.com
AmericanRadioHistory.Com
nREATHTAKING!
heads . ..
ADVERTISING
INDEX
or tails
YOU WIN
•
Unequalled perfectioll of tonal
reproductioll-aHd this HelV stereo
cartridge saves I1tany ti'·Hes its cost
by greatly illcreasiHg the life of your
valHable records aHd styli.
insist OH the ESL Gyro/jelVelthe oHly stereo cartridge approved by
the High Fidelity Consumer's Bureau
of StaHdards. O,t/y $69'95·
•
45
12
80
70
77
78
79
79
72
76
III
61
6
Belden .. .. ...... . ... . . .. .....•.... 27
Bell Te lephone Labo rato ries . .. .... . . . 16
Bogen- Prest o Company ......... . .. .. 51
Briti sh Industries CC'rpora ti on . facing p. I, 3
Cl assified
Picking and choosing ••• flipping a coin
•.• there's no chance of 'goofing' with a
Partridge transformer. They're the
finest transformers made-experts agree
and
invariably
specify them.
Flip a nickel if
you wish but
always call
Partridge ••. that
is, if you want a
winner.
..................... . .. . 78
Duotone Company. Inc . . . . . . ..•.. . 4. 53
Durant Sound Company ... .. . . ...... 70
Dynaco, Inc.
. . . . . . . • • . . . .. 73
FOR LISTENING AT ITS BEST
Electro-Sonic
Laboratories, Inc.
Dept A' 3 5-54 36th St· Lon g !s]andCity6,NY
YOJ/'ll waitt tile lIew ESL Gyro/balallce stereo arlit
tltat malies all cartridges sOlflld better! Olf/y$3 4.95.
ps:
--
Acoustic Research , Inc . . . . . . . . . . . 44,
Acro Products Co.
. . . . . . . . . . . ..
Allied Radio Corp.
. .....• . .... . .
Altec Lans ing Corporation . ....... 5,
Amperex El ectronic Corp. . . . ........
Amp lifier Corp . of America . .. . ...
Apparatus Development Corporation ..
Arkay . ......... . .... .... ...... ....
Atlas Sound Corp. . . ....... ... . .. ...
Audio Bookshe lf . .. . . ..••.. ... .. . ..
Audio Dev ices. Inc. .... . . . . . . . Cov.
Audio Fi delity. Inc ...••... .. . . . . 55,
Audioge rsh Co rp. .......•• ... . . .. . . .
CIRCLE 80A
save on
S...ereo hi-fi
EICO
...................•......
El ectro-Sonic Labora tol ies .... . .......
Electro-Vo ice Inc . . . . . ... .. .... . Cov.
El ectro-Voice Sound Syste ms . ... ......
Ercona Corporation ........ .. .... 78,
Fishe r Radio Corpo ration
Fukuin Electric (Pioneerl
II
80
IV
79
79
.... . 25, 27
... . . ... .. . 39
Genera l Electri c ... . .... . . . ..... . ... . 31
Goth am Audio Sales Co., Inc . . . . . . .. . . 35
Grado La boratories ................. 66
Write now (or (rce Brochure and name
or nearest dealer.
Sole U.S. Rep.
M.
SWEDGAL
Dept. A6, 258 Broadway, New York 7, N.Y.
Telephone : WOrth 2-5485
CIRCLE BOC
Heath Company ... . .... .... . ... .. . 7-9
J ansZen Loudspeakers .... . .. . •. . . . .. 67
Key Electronics ...... ..... . . ....... 79
Kie rulff Sound CorpDration .. .. ....
79
KLH Research & Development Corporati on 74
Don't
La nsing, Jam es B. Sound, Inc . . . . . . ... . 13
Marantz Company . .... . ........... . 75
Neshaminy El ectronic Corp. ....
67
Newcomb Audio Products Co. . .. . . .. .. 29
ORRadio Industries, Inc.
components __ •
everything in
STEREO!
Here's your complete, money-sa ving
guide to Hi-Fi! See how you save on
ALLIED-recommended complete systems,
including the latest in thrilling Stereo.
Choose from the world's largest stocks
of components (amplifiers, tuners,
changers, speakers, enclosures, recorders, accessories). Want to build-yourown?-save up to 50 % with our exclusive Hi-Fi KNIGHT-KITS! Easy terms
available. For everything in Hi-Fi, for
every thing in Electronics, get the 452page 1959 ALLIED Catalog!
ALLIED RADIO
~~I-t-ft~
I
I
I
I
ALLIED RADIO, Dept. 17-F9
100 N. Western Ave., Chicago 80, III.
' 0 Send FREE' 1959 ALLIED 'Catalog
:
Address _ _ _ _ _ _ _ _ _ _ _ __
Name ___________________________
_______
__
_State___
_ _ _ _ _ JI
I~ _City
Zone
__
_
..... • .... .. 32
Partridge Transformers
.. . .... . .... .
Picke rin g & Compa ny ..... . ... . .. ....
Pil ot Radio Corporation ........• . ....
Preci se Deve lopment Corp ....... ......
Professional Directory .........
Radio Corporation of America .... Cov.
Radio Shack Corporation . . ....... . ...
Rek -O- Kut Co. , Inc ............• . .. ..
Res lo ... . ... . ... . .... . ...... .. ....
Ride r, J ohn F. , Publisher, Inc . . . . • •.. . .
Roberts Electronics Inc . . . ............
that
80
15
4I
47
79
word!
II
65
49
79
79
71
Scott, H. H .. Inc . . . ... . ... ... .. .... . 69
Sherwood El ectronics Laboratori es ... .
Soundcraft Corp . . .. . ............. ... 77
Stromberg-Carl son , A Division of
General Dynamics Corporation . . 62, 63
Tandbe rg .. . .... .... . . . . ........ 2, 58
Tannoy . . . .. .. . .•..........•...... 71
United Audio . . . . . . . . . . . . . . . .
37
University Loudspeakers. Inc . . .. . . .. .. 59
Viking of Minneapo lis ... ........ . . . . .' 33
Vitavox . .. . ... ... .. . ... .. .. ..•. . . 78
Weathers Ind ustri es .... . . . .... . •.... 43
"Frightened to death" is no figure of speech where cancer is
concerned. Each year thousands
of Americans lose their lives
needlessly because they were too
terrified about cancer to even
learn facts which could have
saved their lives! Learn how ~
to protect yourself and your
family by writing to "Cancer,"
c/o your local post office.
American Cancer Society
CIRCLE 80B
80
AUDIO
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AmericanRadioHistory.Com
•
®
JUNE, 1959
Audiotape speaks for itself" in a spectacular recording
-available in a money-saving offer you can' t afford to miss!
U
HERE'S a reel of musical excitement t hat belongs on
every tape recorder. "B lood and Thunder Classics"
is a program of great passages of fine music, specially selected for their emotion al impact.
The makers of Aud iotape have not gone into the
music business. They are simply using this method
to allow Audiotape to "speak for itself." This unusual program shows you how vibrant and colorful
music can be when it is recorded on AucZiotape.
"B lood and Thunder Class i cs" i s availab le
RIGHT NOW from Audiotape dealer~ everywhere.
(And only from Audiotape
dealers.) Ask to hear a portion of the program, if you
like. Then, take your choice
of a half-hour of rich stereo
or a full hour of dual-track
monaural sound - both at
7Y2 ips. Don't pass up this
unusual opportunit y.
DETAILS OF THE ,PROGRAM
The stirr ing "Blood ~ nd Thunder Classics"
program incl udes these colorful selections:
Tscha ikowski
Sibelius
de Fa ll a
. . Russ ian D ance
. . f rom Fin landia
. . Dance of T error, Ritua l
Fi re Dance ( EI Amor Brujo)
B ra h ms
. . from Sy m phony No.4 in E Minor
Khatchaturian ' . . Sa be r Da n ce
St ra vi nski
Inferna l Dance o f King Kastchei,
Finale (Firebi rd Su i te)
Beethov e n
Ode to J oy (Sy m phony No . 9
i n D Mino r)
D E TAILS OF THE OFFER
This exciting r ecording is available in a special bonus pa ckage at all Audiotape dealers.
The package contains one 7-inch reel of
Audiotape (Type 1251, on 1 V2 -mil a cetate
base) and th e valuable "Blood and Thunder
Classics" program (professionally recorded
on standard AUdiotape). For the entire
package, you pay only the price of two boxes
of Type 1251 Audiotape, plus $1. And you
have your choice of the half-hour stereo program or the full-hour monaural version.
Don't wait. See your Audiotape dea ler now.
•
•
•
•
•
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•
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AU DIO DEVICES , INC. , 444 M ad ison Av e., N . Y. 22, N . Y.
In Hollywood, 840 N. Fairfax Av e. • In Chicago, 5428 N. Mi lwaukee Ave .
www.americanradiohistory.com
AmericanRadioHistory.Com
I
IHEAR PAGING
!I, C learer•• • Eas.ier
I
~
®
SAVE MONE.Y,
adva nced enginee,ing assu'es
TOO!
.
, ) \ CLEARER COVERAGE with FEWER SPEAKERS
•.. improves efficiency ... reduies listener fatigue
Every installation further proves the efficiency, utility,
I and economy of E-V sound projectors. Messages become
I
easier to understand without listener fatigue. At the
same time, you save cost by using fewer speakers for
proper coverage of the listening area. Wherever paging
is required, get the benefit of natural voice reproduction.
Choose the Type Designed to Meet Yoilr Paging Needs
WIDEST DISPERSION. Exclusive CDP dual-diffraction
design * gives uniform, wide angle coverage at all frequencies ... no dead spots, no hot spots. Exclusive E-V
compound horn reduces compression distortion to as
low as 2% at full power-thus assuring minimum listener
fatigue at any sound level. High efficiency performance
cuts the need for costly high power amplifiers.
newly designed
reentrant projector provides highest intelligibility at
lowest cost where sound must be concentrated. Handles
twice the power of conventional speakers, for greater
penetration.
j CONCENTRATED COVERAGE. E-V
Model 847 25-watt COP. Has two coa xially-mounted horns working from opposite sides of a single diaphragm : Special edgewise·wound voice
coil provides 18% greater efficiency. Wide-range response : 250-10,000 cps .
Sound pr,essure level: 114 db. Dispersion : 60· x 120·. Imp. : 16 ohms. Indestructible fiberglass horn . Size : 11 :){" x 7:){" x lOY." dee'p . Net wt. 6X Ibs.
List Price, $46.33
Modet 847-45 COP with 45-ohm voice coil for intercom applications .
List Price , $47.83
.
Model 844 30-watt Reentrant. Diecast aluminum horn, with removable driver, and universal mounting bracket. Designe'd for easy servicing
with field-replaceable voice coil. Wide-range response: 250-10,000 cps .
Dispersion : 90· . Sound pressure level : 120 db. tmp ., 8 ohms. S ize: 9Ys"
diam. x 8Y. " deep. Net wt. 5 Ibs. 10 oz.
List Price, $34.50
Model 844-45 Reentrant with 45-ohm voice coil for intercom use.
List Price, $36.00
(Sound p'ress ure level measured at 4 ft. on axis from 500 to 1500 cps with full rated input.)
,
E: V sound projectors are extra-rugged for long-life service indoors or outdoors . They are weatherproof, blastproof, splashproof. Actual comparison
.. on the job proves their superiority.
..,
:. -:,\
" Design Patent 169,904
.
Write for Bull etin 258A to Dept. 69·A
iva Finer
Choice than
Other Popular Models in the Complete E-V Line
For large area sound reinforcement: Model 848 30-watt
COP or Model 848L T 30-watt Long-Throw COP, at
$75.00 list. For high-fidelity voice and music : the E-V
Musicaster at $80 .00 list. Remember too , you get even
better sound when you choose an E-V high-fidelity profess ional microphone from today's most complete line.
Musicaster
ELECTRO-VOICE, INC •• BUCHANAN, MICHIGAN
www.americanradiohistory.com
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