Audio August 1957
Bogen High Fidelity
"Price and features have sold me on Bogen."
-Richard B. Roetter, Newark Electric Company, Chicago
Audio consultants, such as those quoted here,
don 't use words like "marvelous", "superb" and
" blue chip" lightly. Their studied opinions, and the
fact that more Bogen high-fidelity components are
in use today than any other brand , are ample proof
that for more engineering "firsts", more years of
brilliant performance . more rugged good looksthe choice is Bogen.
TUNERS: .. FM 50 FM TUNER : $84.50. Enclosure
$7.00. 2 R775 DeLUXE TUNER-PREAMP: $249.50.
Enclosure, $8.00. AMPLIFIERS: 3 DB130 35-WATT
AMPLIFIER : $115.00. Enclosure, $7.50. 4 DB110
12-WATT AMPLIFIER : $64.50 including enclosure.
S D070 70-WATT POWER AMPLIFIER : $129.50
including enclosure . RECEIVER: 6 RR550 FM-AM
25-WATT RECEIVER: $224.50. Enclosure, $8.00.
STEREO PLAYBACK: .., ST10 DUAL PREAMP and
10-WATT AMPLIFIER: $52.50. With eRclosure,
$59.50. Write for complete catalog and/or send
25c for new 56-page "Understanding High Fidelity, "
David Bogen Co . , Inc . Box 500, Paramus, New Jersey
"Superb instruments that
please the cORnoisseur."
Harry Shaffer, Hollywood
Electronics, Hollywood
-.A UNITRONICS CORPORATION AFFIL.1ATE
AUGUST, 1957
VOL. 41, No.8
Successor to RADIO, Est. 1917.
COMPARE ...
you will agree
ENGINEERING
MUSIC
SOUND REPRODUCTION
C. G. McP"oud, Editor and Publisher
R enry A. Schober, Business Manager
Rarrie K. Richardson, Associate Editor
Joan Dioguardi, Assistant Editor
Janet M. Durgin, Production Manager
Edgar E . Newman, Circulation Director
Sanford L. Cahn, AdYe,·tising Direclo~
Special Repre3entative-
H . Thorpe Covington,
814 L incoln St., Evanston, Ill.,
DAvis 8·8874
Feedba ck ton e
control s
EF86 low-noise
preamp . t ube
Presence- rise
. control
Tape-h ea d
equal,ization
West .RepresentativeSanf01'd R. Cowan, 300 W. 43rd St.,
N ew York 36, N. Y.
.I{ id
In puts, selectabl e
at front pa nel
'"
6
Microphone
eq ual ization
W est Coast RepresentativesJames C. Galloway and J. W. Harbison,
6535 Wilshire Boulevard, Los Angeles 48, Cali f.
Tape-monitor
swi tch
Dampi ng-fac tor
se lec tion
1M dis tort ion at
20 watts
1.0
12db/ oct. sc ratch
Iilter
V
12db/ oct. ru mble
lilter
CONTENTS
Audioclinic-J oseph Giovanelli
2
Ca thode-foll ower
r ecordi ng
output
Phono sensi t ivi t y
Letters
6
out put
Unus ed inputs
V
(mv) for full
shorted to prevent cross tal k '"
Editor 's Review
12
High-Quality Treble Amplifier- Cha1'les W . Ha1'1'ison, h .
15
Data is manufacturers' published specificqtions lor
current " flot-cabinet " amplifiers (20 or more wattsJ.
Ef],ualizer Design-N O1'man H. C1'owh'u rst
17
,Technical literature available on request. Write Dept. A·S
Auditor y P erspective- W. B . Snow
20
Understanding Intel'modulation Distortion-Mannie H01'owitz
22
New Products
26
New Literature
27
Record R evue- EdwaHI Tatna ll Can by .......................... .. . . . . .
............. . .. 28
About Music-Ha1'old L aw1'ence ....... .................... .
32
Coming Hi-Fi Shows
33
Audio E T C-Edwa1'd Tatnall Canb y
34
J azz and All Th at- Cha1'les A. R obertson
38
Industry Notes and P eople
47
Advertising Index .....
48
In New York, hear "Accent on Sound" with
Skip Weshn er, WBAI.FM, wee k nights, 9 P.M.
The
complete
home
music
center
Cover Photo Courtesy Kierulff Sound Corporation
AUDIO (titl. recbtered V. S. Pat. Olf.) b pubJIBbed monthly by Radio Magazines. Inc., Henry A. Sthober. President ;
C. G. lIieProud, Secretary. Executl.. and Editorial Ollkes, 204 Front St., ~lineol a , N. Y. Subscription ra_V. 5..
P.......iona, Canada and MeDtO, $4.00 for one year, $7. 00 for two years, an other countries, $~. OO por year. Single
tOpi .. 50¢. Printed In U. S. A. at Lancaster, P&. All rlgbts rese"ed. EnUre tOntents copyright 1957 by Radio Ma,mo .. ,
Ine. Entered u IIeeond Class Matter February 9, 1950 at Ibe Post Omce, Lancaster, Pa. under the Act of llarcb 3, 1879
RADIO MAGAZINES, INC., P. O. Box 629, MINEOLA, N. Y.
AUDIO
•
AUGUST, 1957
.,Only Sherwood funers feature
0.95
~v
FM sensitivity!
FROM TRIAD
AUDIOCLINIC??·
JOSEPH GIOVANELLI ':'
NOTE
High Fidelity
Output
Transl,ormers
For the new
EL-84 and EL-34 Tubes
Some of you ha \'e asked tha t I do not use
your na mes but prefer that I use only initials when yo ur questions al'e to appear in
my column. The question submitted by Mr.
S. W. is, an example. I am, of course, happy
to comply with your wishes. However, unless you specifically say that you do not
wish me to use your name, I shall assume
that I may use it.
Since the Tenth Anniversary issue, in
which my biography appeared, I have received letters from some of yo u with questions concer ning visual aids, such as scopes,
VU meters, and the like. Some have felt
that perhaps these questions were in poor
taste and overstep propriety because I
don't see and therefore cannot make much
use of such devices. Let me assure you that
although I cannot use these devices, I have
had to understand them in order to work
out means for circumventing their use;
also, such an understanding of t hem enables me to talk intelligently with others
whose frame of reference is based on theslJ
visual aids.
l'd like also to remind you to enclose a
stamped, self·addressed em-elope with your
question. You see, whether or not your
questions are suitable for use in this
column, they will be answered by mail.
Your enclosed em'elopes help speed this
process enormou sly. Thank you.
Tuner Output
Triad
Type
Max,
Level
Watts
No.
FOR PP EL·84 (S8Q5)
HSM-1 81
HSM-1 82
S-142A
8000/ 2000 CT
16/ 8/ 4
15
Split Pri mary
8000/ 2000 CT.
Split Primary
8000 CT.
500/ 250/
125
15
16i 8/ 4
15
FOR PP EL-34 (SCA7)
HSM·18S
HSM-187
S·14SA
HSM-192
HSM-193
S-152A
6600 CT.
6600 CT.
16/ 8/ 4
500/250/
125
6600 CT.
16/ 8/ 4
FOR PP Par EL-34 (SeA 7)
25
25
4000 CT,
4000 CT.
65 ,
65
4000 CT,
16/ 8/ 4
500/ 250/
125
16/ 8/ 4
25
65
' Proper taps on Primary for
tapped screen operation .
..1:..
4055 REDWOO D AVENUE. VENICE. CALIF.
812 E, ST ATE STREET. HUNTINGTON. IND ,
A SUBSIDIARY
2
OF
LITTON
I NDUST RIES
Q. I have an FM tlt7l er which is glVtng
?li e considerable t 1'O'uble. E ven after alignInent, thm'e 'Was a seve?'e loss of 01ttPUt,
Tub es test good, selectiv ity see ms good, and
it /i,?II -its on a f ew 71W7'e stations than before . Si,g nal eye is strongly deflected and
sound qual'ity is good. I ILsed to play the
tuner directly into the po'we?' amplifier,
'Which checks good j I got alnple volume
'With the cont'l'ol turned Itp a qUa?'ter of the
'Way. N O'W I must 'inse'rt a separate voltage
ampl'ifier (6J5), afte7' the tuner and, even
so, on some stations have to crank the pot
so far up that hU71'! and bu zz come in f'rom
the tunm', not the voltage 0'1' po'Wer amp lifie7's 'Which are both clean. If there is complete li7ni,t ing on more stations than before,
I aSSU7lte the IF 's a're offe'ring a strong
signal to 1J}te l'imite7's, Have y01t any idea
'Where the ext7'e7ne loss of gain is t aking
place? S,W" Ne'W York, N, y,
A. Low output from your FM tuner may
be attributed to many things: defects in
the limiter circuits, improper alignm ent of
the primary of the discriminator coil, defective components in the stage or stages
immediately following t he discrimina tor, If
possible, check all voltages and resistances;
then check capacitances for possible shorts
or opens, To test for shorts, try to pass a
current through the capacitor, after disconnecting one side of it f rom the circuit
under test. If current can b e passed through
it, t he unit is shorted, If an ohmmeter is
available, measure the resistance of the
capacitor, The resistance of conventional
coupling capacitor approaches infinity, To
check for an open capacitor, you need a
capacitance checker, The procedure consists
of noting the labeled value of capacitance
and comparing it with the measured value.
* 3420 Newki7'k Ave., Brooklyn 3, N . Y.
Replacing Components
Q. On a stmig ht W-illia7nson ampli fier in
fo 'l' seven yea7's, still clean sounding,
'Whi.ch components 'Will need replacing? S.
W., New Yo?'k, N. y,
A. If the unit is still clean sounding, it
pI'obably needs no maintenance. It is possible, however, that some improvement in
performance will result from replacing the
output tubes and the r ectifier,
~tse
Cabinet Bracing
Q. My system is composed of c07nponents
wh'ich I conside7' 7'easonably good, Th e weak
!-ink see7l!S to be t he speaker cab,inet, The
tro~Lble stems f7'om the non-rigidity of it,
Especi,a lly armmd the back panel, it seems
to shake, rattle, and roll, Ho'W can I solidify
the cabinet? It is made of three-qlLarter
inch ply'Wood. The vibration armmd the
back panel is so violent that the scre'Ws
have pulled out more t han once, 'With the
7'eS'lLlt that many of t hem don 't hold any
longer, Would bonding an add'it'ional piece
of ply'Wood to the back help? B. Goerner,
C07'te Madem, Calif.
A. Panel resonances may be broken up
by placing heavy hard wood strips at random points on the offending surfaces, If
vibration occurs at the junction of two
panels, a glue such as Weldwood or Ehner's
glue should be used with the aid of furniture clamps to firm up these joints. This
procedure will probably require taking the
cabinet apart to be able to get the glue
into the proper places. The b ack should not
be glued, however, as it is quite likely that
you will want at some time to gain access
to the interior of the cabinet. However, the
use of many screws plus a layer of weather
stripping, rubber or cork placed between
the back a nd side panels would remove a ll
vibration. If vibration still occurs, it would
be advisable to place some ozite or similar
material on the offending panels. This material is available as the liner for carpeting,
VU Meter
Q. I all! not an elect7'ical eng'ineer, but
a chem'ical engineer 'Who enjoys square·
dance-calling as a hobby, I have been trying to install a VU meter in the a7ltplifier
1tsed 'With the phonograph to play the necessa?'y 7'ecords , I am not interested in actual
db output, but 'Would like to set a record
at a 7'efeTence level on the scale and then
set all succeeding 7'eco7'ds to t hat same
pO'int. The 7'efeTence point w01Lld VQ7'y f7'Om
hall to hall, Can you tell me how to 'Wire
this Ineter into my speaker cb'cuit? George
Cab le, East St. Louis, Ill ,
A. For normal levels that would be expected in your application, the simplest
way of connecting the VU meter to the
speaker line would be to install a lOOO-ohm
potentiomet er directly across the output
terminals of th e amplifier, and connect the
meter from the a rm of the potentiometer
to the grounded end. You would thus have
a continuous adjustment of the meter swing
f rom about a qu a rter of a watt up to the
maximum output of the amplifier. For a
l6-ohm output, the signal across the speaker
is 4 volts at one watt, derived from the
for mula P =E ·IE. Changed around to give
voltage directly, E = V P x E, where P is
the power in watts and E i s the impedance
(Continued on page 37)
AUDIO
•
AUGUST, 1957
$24.50
yes ... b~cause this precision design, by
mcorporatmg the smallest number of pivots,
reduces tra versing friction to an absolute minimum. This also results in the least amount of
wear and tear on records, throu~h the use of
spring-loaded, cone-type ball-bearmg pivots ..•
similar to those you will find in the finest
chronometers. The vertical pivot is a speciallydesigned bearing, combining the features of a
ball-bearing journal suspended on a single ball
thrust.
Infinite versatility! It is the only tone arm
which is fully adjustable in length and tracking
angle. This means that with the Garrard arm,
you can make every adjustment you would conceivably wish to make on a tone arm.
For two reasons: (1) You can set it
for the longest position permitted by the space
you have available now. (2) If you change the
installation, you will be able to readjust this
arm, keeping the important benefits of using a
"longer" arm ••. playing a full 16" record.
Yes, of course. In fact, there are many opinions
regarding optimum tracking angle for any given
length.
Som~ofthe
With the :protractor which is
supplied WIth the tone arm. In
a few seconds, this ingenious
accessory lays out the recommended angle on which to
align the cartridge for the arm
length you are using. Since there are various
opinions regarding the optimum tracking angle
at various radii, this protractor will also enable
you to set the angle at any desired radius.
significant questions
being asked about it
... and their
exciting answers
Yes, the removable head will take just
about any cartridge on the market.
This tone arm is designed to be used
with any transcription turnta ble, and adjusts
easily for height and stylus pressure. The special
templates supplied show you the exact mounting location. Incidentally, the instructions are
the clearest and most complete we have ever
seen with a tone arm.
It is at your high fidelity dealer, and you
will certainly recognize it through its
handsome appearance . • . glistening
chrome with white enamel. Look for it
in a distinctive blue and white bOll:.
DEPT. GK·ll. 'JARRARD SALES CORPORATION • PORT WASHINGTON, N. Y.
·New
-E- SIGNAL BURST
"
PRINT·THROUGH
CONVENTIONAL TAPE
Strip chart clearly· shows print-through signals before and after I-second , l·kc tone bursts on a conventional tape stored 5 minutes.
AUDIO
•
AUGUST, 1957
Another 3 M first'
gold seal professiona l tape
cuts print level 8 db!
Is print-through a problem with you? Even the most
carefully made tape recordings ~ be marred by
potency, greater sensitivity. Available in widely used
2400 ft. length, as well as 1200 and 4800 ft. lengths.
print-through ... layer-to-Iayer signal transfer in tape
Today-buy new "Scotch" Brand Low-Print Mag-
wound on rolls. Solve your problem by using new
netic Tape in the box with the bright gold seal. Sure
"Scotch" Brand Low-Print Magnetic Tape with the
sig n of quality !
lowest print level of any tape on the market.
New gold seal Low-Print Magnetic Tape gives you
8 db lower print level. It's the first and only tape to
reduce print-through to a point below noise level on
most professional machines. First tested commercially a year. ago, this new tape is the product of 8
years of intensive research in 3M Company laboratories .
Superb recording characteristics are another feature of new "Scotch" Brand Low-Print Magnetic
Tape . New oxide construction provides increased
The term "Scot ch " and the plaid design are registered trademarks for Mag neti c Tape made in U .S .A . by MINNESOTA MINING
AND MFG . CO., St . Paul 6, Minn . Export Sal es Office : 99 Park
Avenu e, New York 16, N . Y. © 3M Co ., 1957
LOW-PR IN T TAPE
Stri p chart with sam e signal proves t hat new " S cotch" Brand Low-Pri nt T ape stored f or same time has greatly red uced print-throu gh .
AUDIO
•
AUGUST, 1957
5
I
ATWI
LETTERS
world famous quality ca rtridge - now at
W
LO
PRICES
Microphone Correction
SIR:
I suppose it is a sigu of naivete to read
an interview iuvolving onesel£ and react
with a "Did I say thaH" I was generally
gratified to find my pontifications set forth
iu the Jul)' JAZZ AND ALL THAT, even if
one or two of the "quotes" seemed com·
pletely strange to me. Actually, most of
the errata are of a comparatively trivial
natu re, involving shades of meaning to
which I am probably the only one likely to
be sensitive.
However, there is one correction that I
find necessary to make. The measurements
made at RCA Camden comparing my modi·
fied 44A and RCA ' s laboratory standard
microphone did not definitely establish that
the 44A had "superior performance below
50 cps and above 10,000." They did estab·
lish that the 44A had ?n01'e output at these
frequencies, but RCA's engineers would
question t he evalua tion "superior," since
'it is their contention, supported by considerably greater knowledge, experience,
and also by a carload of test equipment,
that the greater low-frequency response of
my microphone is due to undamped resonance of the ribbon. It is my contention,
supported only by speculation and wishful
thinking, that the fact that my ribbon has
only half the mass and is also less springy
th an theirs has reduced bass resonance
effects to negligibility, since the ribbon is
subject to considerable air loading and
magnetic damping.
None of my acquaintances at RCA had
anything to say about the superior response
of the modified 44A above 13,000 cps.
D_~VID B. HANCOCK,
127 West 88th St.,
New York 24, N. ·Y.
More Corrections
SIR:
If you have a hi-fidelity system, bring out its finest tonal values ... and
save money at the same time! Because ... thanks to the tremendous
popularity of our MIRATWIN cartridges, we have been able to effect
considerable manufacturing savings .. . and we're passing them along
to you! Remember, MIRATWIN is as smooth and sensitive a cartridge
as man can make ... acclaimed by audio engineers and music appreciation enthusiasts alike. So enjoy it in yOU?' system. Instant Stylus
Replacement .. . Ask your dealer to give you an A-B Test tomorrow.
MIRATWIN CARTRIDGES
MST-ID ~ingle Diamond _ _ _ _ $26.50
MST·IS Single Sapphire___ 10.00
MST·2D Dual-l Sapph., 1 Diam._ 31.50
MST-2A Dual Sapphire
15.00
REPLACEMENT STYLI
DM-2 MicTo·Diamond _ _ $16.50
DN-2 Standard Diamo1ld_ 16.50
SM·2 Micro-Sapphire__
5.00
SN·2 Standard Sapphire_
3.00
FAR AHEAD> THE FINEST BY F,\R
A.uOIOGERSH CORP.
WORTH 6-0BOO
6
514 BROADWAY, NEW YORK 12, N .
IN CANADA: Atlas Radio Corp., Ltd .. Toronto
Y.
I would like to conect an error and
clarify two points in connection with my
~rticle, " Above All, The Ear," in the May
Issue;
~ stated t,hat one volt equals 10' ergs.
ThIS absurdIty resulted from my leaving
off the end of the sentence, which should
have read: " . . . one volt is equal to 10'
ergs Pc?' ampel'e second."
As I had e:xpeeted, quite a number of
people were astonished by the statement
" ... there is 110 known method af measUl'ing sound exactly. " Their incredulity
might have been tempered somewhat had I
made it more clear that the quality of
~ound to which I was referring was loudness as opposed to intensity or pressure.
Loudness is subjective, and like pleasure or
pain, cannot be measured with physical
a.pparatus. I had thought that this point
. would be clear inasmuch as the topic of
almost the entire article was the subjectivity of sound.
There has been some small objection to
my rath er loose reference to the decibel
as a "nnit of sound." Although the reference was not quite punctilious, I believe
that most people knew what was meant.
One reader attempted to correct me on this
point by informing me that the decibel was
, 'a unit on the scale of sound pressure
leveL" This, of course, is not correct since
the decibel is 11 unit on the scale of sound
in.tensity level. Sound intensity and sound
pressure a re not at all the same; ill fnet,
AUDIO
•
AUGUST, 1957
.
~hey a ;e not even proportion al, iutensity
mcreasmg at the square of pressure.
The above facts can be verified in Dniversity Phys'ics b y Sears and Zemansky
(Addison &, W esley, 1955).
JAMES A. NUNLEY
225 "J" Street, '
Salt Lake City 3, Utah
(We thought Mr. N should have t il e last
lVord, even if belatecl. En. )
Engineer PLUS Musician-not VS _
you
SIR:
can
Of t he many r elationships bet"'een t he
a rts a nd the sciences, none is more interesting or more compatible t ha n that between
music a nd electronics. Electronics i s t he
j unior partner, of co urse, b ut its contribu.t ion is full measure.
Of all t he t hings that can be said a bout
audio, t he most inaccura t e would be t hat
it is static. In general, t he aim a nd orientation of a udio has been good mu sic. Progress has been made eyen while exploring
the technica l fri nges. For example, we
passed through a period recently when
engineers- or " music lover s," I am not
sure which-li stened through t heir slide
r~ l es. We awakened fina lly to t he realizahon that perfection is a wi ll-of-the-wi sp.
It was the era of "High Futility."
Today we see~n to be experiencing :1
r eturn-to-the-muslc movement. Quite properly we use as our standar d fo r judging
system or total performance the original
itself_ Wc might bOITOW a line f r om T eahmtse of the AUg1tst Moon- " a step backward in the right direction. "
Now the question-just how preoccupied
with the sound of music shall we get ~
Must we surrender engineering methodsanalysis, objective measurement, universal
standard s- simply becanse we suddenly discover t hat the final result of our work is
to be judged subjectively ~ I , for one, h ave
had enough of designing for sound effects
and testing to the criteria of a ural fatigue.
Cont rols to optimize system performance
under varying conditions are one thing'
those used to rewrite the music or und ~
the work of the conductor a r e quite another. Stravinsky and Strauss do not soun d
alike alive; if we r elax our engin eering
discipline they may on playback.
To me it is a ridiculous sit uation wher ein
engineers, professing an interest in music
lapse into acoustic surrealism. Equall);
ridiculous, but less prevalent, pel"ll aps, a r e
the attempts of "musician-designer s"
(e.g., the muddy-clean boys) to achieve
"presence" without understanding fr equency-response characteristics
(candid
Canby is an accepted exception ).
This is not a question of hobbyist vs .
professional. Nor is this a suggestion that
mnsicia.ns and engineers stay each in his
own backyard. Each needs the other. Beyond the t ea m effort r equired to provide
a wide segmen t of the public with good
well reproduced music is the n eed of th~
musician for an accurate device to evaluate
his own technique. Likewi se the a udio engineer needs accurate sources and measuring
instrument s if he is to evalua te his designs.
While the audio engin eer supplies the" laboratory" equipment used by the musician
the con verse is not true.
'
Let's let the musicians handle the tones
alld t he engineers the frequencies. In t his
way the worth of the whole will exceed t he
sum of t he parts.
JOE DICKEY
Lindamoor,
Annapolis, Md.
AUDIO
•
AUGUST, 1957
enjoy
the
best
in Hi-Fi
XA-100 is the 4 speed
record chan ger th at mak es Hi-Fi easy
for everyone. It does everything automatically, at the push of a button ... starts, stops, repea ts, pauses, filters! It intermixes 10" and 12"
records! It changes from automatic to manual in a moment. And it
has the uniqu e "free-wheelin g" tone arm that can't jam! No other
r ecord-player h as aU these features! So get a MIRACORD XA-100, if
you're assembling your own system. . or having your $
50
dealer hook-up a system for you!
'MIRA CORD
67'
. .. and for transcription quality
in a 4-speed manual player . ..
MIRAPHON
XM-110A
at only $37 50
complete with every feature to
satisfy the most critical listener!
as " your dea.ler fo r a. demo'is tra.tion
FAR ABEAD) Tlt E FIN EST
BY
FAR
AUDIOGERSH CORP.
WORTH 6-0BOO
514 B ROA D WAY, NEW YORK 12, N . Y .
IN CANADA : Atlas Radio Corp .. Ltd., Toro nto
7
treat your family
to all the fun and enioyment
of fine high fidelity at
one-half the price you
would expect to pay
HERE'S ALL YOU
NEED
HI-FI
to build your own
HEATHKIT
HIGH FIDELITY FM TUNER KIT
FM TUNER
This FM tuner is your least expensive source of high
fidelity material! Stabilized oscillator circuit assures
neg ligible drift after initial warmup. Broadband IF
circuits assure full fidelity, and 10 microvolt sensitivity
pulls in stations with full volume. High-gain cascode
RF amplifier, and automatic gain co ntrol. Ratio detector
gives high-efficiency demodulation. All tunable components prealigned. Edge- illuminated dial for easy
tuning . Here is FM for your home at a price you can
afford. Shpg. Wt. 7 Ibs.
MODEL FM-3A $25.95 (with cabinet)
HEATHKIT
BROADBAND AM TUNER KIT
This tuner differs from an ordinary AM radio in that it
has been des ign ed especially for high fidelity. Th e
detector uses crystal diodes, and the IF circuits are
"broadbanded" for low signal distortion. Sensitivity
and selectivity are excell ent. Quiet performance is
assured by 6 db signal-to-no ise ratio at 2.5 uv. All
tunable components prealigned. In corpo rates AVC,
two outputs, and two antenna inputs. Edg e-li ghted
glass slide rule dial for easy tuning. Your "best buy"
in an AM tuner. Shpg . Wt. 8 Ibs.
MODEL BC-1A $25.95 (with cabinet)
AM TUNER
HEATHKIT "MASTER CONTROL"
PREAMPLIFIER KIT
PR EAMPLIFIER
8
This unit is designed to operate as th e "master control"
for any of the Heathkit Williamson·type amp lifiers, and
includes features that will do justice to the finest program material. Frequency response within ± 1Yo db
from 15 to 35,000 CPS. Full equali zation for LP, RIAA,
AES, and early 78's. Five switch-selected inputs with
separate level controls. Bass and treble control, and
volume control, on front panel. Very attractively styled,
and an exceptional dollar value. Shpg . Wt. 7 Ibs.
MODEL WA-P2 $19.75 (with cabinet)
AUDIO
•
AUGUST, 1957
HEATHKIT "BASIC RANGE"
HIGH FIDELITY SPEAKER SYSTEM KIT
Th e ve ry popu lar model SS -1 Speaker System provid es amazin g high fidelity performance fo r its size. becau se it uses
high-qual ity speakers, in an enc losure espec ially des igned to
receive them.
It features an 8" mid-range-woofer to cover from 50 to 1600
CPS, and a compress ion-type tweete r w it h f lared horn to
cove r f rom 1600 to 12,000 CPS. Both speakers are by Jensen.
Th e enclosure itse lf is a ducted-port bass -reflex unit, measuring 11 y," H x 23" W x 11 %" D and is co nstru cted of venee rsurfaced plywood, y," thick. A ll parts are precut and predrilled for quick assembly.
Total frequ ency range is 50 t o 12,000 CPS, within ±5 db.
Impedance is 16 ohms. Op erates with th e "Range Ext ending"
(SS-1 B) speaker system kit later, if greate r frequency range
MODEL SS-1 $39.95
is des ired. Shpg. Wt. 301bs.
,:".
"6ASIC'.; SPEAKER SYSTEM
HEATHKIT "RANGE EXTENDING"
HIGH FIDELITY SPEAKER SYSTEM KIT
The SS -1B uses a 15" woofe r and a smal l supe r-t weeter_to
supp ly very high and very low f requ encies and f ill out th e
resp onse of·th e "Basic" (SS-1) speaker system at eac h end
of th e aud io spectru m. Th e SS-1 and SS-1 B, comb ined, pro vide an overal l response of ±5 db f rom 35 to 16,000 CPS. Kit
includes circ uit for crossover at 600, 1600 and 4000 CPS.
Impedance is 16 ohms, and power ratin g is 35 watts . Measures
29" H x 23" W x 17Y," D, and is co nstructed of ve nee r- surfaced
plywood, W thick. Easy to build! Shpg. Wt. 80 Ibs.
MODEL SS-1 B $99.95
__ _-and save!
RANGE EXTENDER
HEATHKIT "LEGATO"
HIGH FIDELITY SPEAKER SYSTEM KIT
Th e fine quality of the Legato Speaker System Kit is matched
on ly in the most e.xpens ive speaker- systems available. The
listenin g expe ri ence it can bri ng_ to you approaches the
ultimate in esthetic satisfact ion.
Frequ ency res pons e is ±5 db 25 to 20,000 CPS. Two 15"
the ater-type A ltec Lans in g speake r-s cO\/e r 25 to 500 CPS, and
an Altec Lansin g high freque ncy driver wit h sectora l horn
cove rs 500 to 20,000 CPS. A precise amoun t ,of phase sh ift in
the crossove r networll brings the high-f requency chan nel
into phase with the low-frequency channe l to eli minate peaks
or valleys at the crossove r po int. This is one reason for the
mid-rang e "p resence " so evident in th is system design.
Th e attractive ly sty led "contemporary" enc losu re emphasizes simplicity of lin e and form to blend with al l fu rni sh in gs.
Cabinet parts are prec ut and predril led f rom %" veneer surfaced plywood for easy assemb ly at home. Impeda nce is
16 ohms. Power rating is 50 watts fOt' program material. Ful l,
smooth f requ ency response assures you of outstand ing high
fidel ity performance, and an unfo rg ettab le listening expe rience. Or-d er HH-1-C (birch) for light finishes, or HH-1-CM
(mahogany) fo r dark f inishes. Shpg . Wt. 195 Ib s.
MODELS HH-1-C or HH-1-CM $325.00 each
HEATHKITS
World's finest
electronic equipment
in kit form ...
Pioneer in
" do-it-yourself"
electronics
HEATH
COMPANY
"LEGATO" SPEAKER SYSTJM
A subsidiary of Daystrom, Inc.
Benton Harbor 25, Mich.
AUDIO
•
AUGUST, 1957
9
25-WATT AMPLIFIER
70-WATT AMPLIFIER
ELECTRONIC CROSS-OVER
•
.easy-to-build designs by
~nsure
I
You get more comprehensive
assembly instructions, higher
quality circuit components, and
more advanced design features,
when you buy HEATH hi-fi!
HEATHKIT 70-WATT
HIGH FIDELITY AMPLIFIER KIT
This new amplifier features extra power
reserve, metered balance circuit, variable
damping, and silicon-diode rectifiers , reo
placing vacuum tube rectifiers. A pair of
6550 tubes produce full 70·watt output with
a special·design Peerless output transformer. A quick-change plug selects 4, 8
and 16 ohm or 70 volt output, and the
correctfeedback resistance . Variable damping optimi zes performance for the speaker
system of your choice. Frequency response
at 1 watt is ± 1 db from 5 CPS to 80 KC with
controlled HF rolloff above 100 KC. Harmonic distortion at full output less than 2%,
20 to 20,000 CPS, and intermodulation dis·
tortion below 1% at this same level. Hum
and noise are 88 db below full output.
Variable damping from .5 to 10. Designed
to use WA-P2 preamplifier. Express only.
Shpg. Wt. 50 Ibs. MODEL W-6M $109.95
10
HEATHKIT 2S-WATT
HIGH FIDELITY AMPLIFIER KIT
HEATHKIT W-3AM
HIGH FIDELITY AMPLIFIER KIT
The 25·watt Heathkit model W·5M is rated
"best buy" in its power class by indepen·
dent critics! Faithful sound reproduction is
assured with response of ± 1 db from 5 to
160,000 CPS at 1 watt, and harmonic distor·
tion below 1% at 25 watts, and 1M distortion
below 1% at 20 watts. Hum and noise are
99 db below rated output, assuring quiet,
hum·free operation. Output taps are 4, 8
and 16 ohms. Employs KT66 tubes and
Peerless output transformer. Designed to
use WA·P2 preamplifier. Express only .
Shpg . Wt. 31 Ibs .
MODEL W-5M $59.75
Features of this fine Williamson·type ampli·
fier include the famous Acrosound model
TO·300 "ultralinear" transformer, and 5881
tubes for broad frequency response, low
distortion, and low hum level. Response is
± 1 db from 6 CPS to 150 KC at 1 watt.
Harmonic distortion is below 1% and 1M
distortion below 1.3% at 20 watts. Hum and
noise are 88 db below 20 watts. Provides
output taps of 4,8 or 16 ohms impedance.
Designed to use WA·P2 preamplifier. Shpg .
MODEL W-3AM $49.75
Wt. 29 Ibs.
HEATHKIT
ELECTRONIC CROSS-OVER KIT
This device separates high and low fre·
quencies electronically, so they may be fed
through two separate amplifiers driving
separate speakers. The XO-1 is used be·
tween the preamplifier and the main ampli·
fiers. Separate amplification of high and
low frequencies minimizes 1M distortion .
Crossoverfrequencies are selectable at 100,
200, 400, 700, 1200, 2000, and 3500 CPS.
Separate level controls for high and low
frequency channels. Attenuation is 12 db
per octave. Shpg. Wt. 6 Ibs .
MODEL XO-1 $18.95
HEATHKIT W-4AM
HIGH FIDELITY AMPLIFIER KIT
A true Williamson·type circuit, featuring
extended frequency response, low distor·
tion, and low hum levels, this amplifier can
gi ve you fine listening enjoyment with a
minimum investment. Uses 5881 tubes and
a Chicago'standard output transformer.
Frequency response is ± 1 db from 10 CPS
to 100 KC at 1 watt. Less than 1.5% harmonic distortion and 2.7% intermodulation
at full 20 watt output. Hum and noise are
95 db below full output. Transformer tapped
at 4, 8 or 16 ohms. Designed to use WA-P2
preamplifier. Shipped express only. Shpg.
Wt. 28 Ibs.
MODEL W-4AM $39.75
AUDIO
•
AUGUST, 1957
W-3AM
2O-WA TT AMPLIFIER
W-4AM
?O·WATT AMP LI FIER
HEATHKITS
.. . top HI-FI performance
World's finest
electronic equipment
in kit form ...
HEATHKIT A-9C
HIGH FIDELITY AMPLIFIER KIT
This amplifier incorporates its own preamplifier for self-contained operation. Provid es 20
watt output usin g push-pull 6L6 tubes. Tru e
high fide lity for the home, or for PA applications. Four separate inputs- separate bass and
treb le controls-and volume control. Covers 20
to 20,000 CPS within ± 1 db. Output transfo rmer tapped at 4, 8, 16 and 500 ohms. Harmonic distortion less than 1% at 3 db below
rated output. Hi'g h qual ity sound at low cost !
Shpg. Wt. 23 Ibs.
MODEL A-9C $35 .50
HEATHKIT A-7D
HIGH FIDELITY AMPLIFIER KIT
This is a true high fidelity ampl if ier eve n
though its power is somewhat limited. Bu ilt· in
preampl if ier has separate bass and treb le controls, and vo lume control. Frequ ency response
is ± 1y, db from 20 to 20,000 CPS, and distorlion is held to surp risingly low level. Outp ut
transforme r t apped at 4,8 or 16 ohms. Easy to
bu ild, and a fine 7- watt performer for one just
becoming interested in high fidelity. Shpg. WI.
MODEL A -7D $17.95
101bs.
Model A -7E : Same as the above except with
extra tube stage for added preamplification .
Two switch-selected inputs, RIAA compensat ion, and plenty of gain for low·level cartridges.
Sh pg. WI. 10 Ibs .
$19 .95
--
AUDIO
•
AUGUST, 1957
HOW T O ORDER _ . _
Just id entify th e kit you desire
by its model number and send check or
money order to address below. Don't hesitate
to ask about HE A TH TIME
PA YMENT PLAN.
P ioneer in
" do-it-yonrself"
electronics
HEATH
COMPANY
A subsidiary o f Daystrom, Inc .
Benton Harbor 25, M i ch.
NAM E____________________________________________
ADDRESS ______________________________
CIT Y&STA TE ___________________________________________
Please send F R E E
Heathkit Catalog
...... . ...... . ... ... . . .. .. ...................... . .. .. ... .. ... .................. .. .. .. .. .. ........................................ . ... .... .... .. ...:
11
EDITOR'S REVIEW
MONEY IN COVER PHOTOS
M
in our home componenthigh-fidelity systems, and others of us are
always looking for ideas for attractive ways to
use them in our own homes-possibly not from any
intention of duplicating exactly what another has done
but perhaps just for an idea or two for some means of
adapting the equipment to the room. Since our new
cover design involves photographs, we believe that
readers might enjoy "making" the cover with especially interesting pictures of how they solved the problem of installation in a convenient and attractive
fashion-one that is accepted by everyone in the household, particularly by the "little woman."
Therefore, we will pay ten dollars for each photo
accepted for use on our new cover. Photos must be at
least 8 x 10, glossy, sharp, and of good photographic
contrast. Those which are not accepted can not be
returned, and if any people appear in them a signed
model release must accompany the photo ..
This month's cover shows an attractive installation
executed by Kierulff Sound Corporation of Los
Angeles and their ten dollar check is already on the
way. Will your installation be next?
ANY OF US TAKE PRIDE
DOODELAC, ANYONE?
We have all heard of the Studillac-a combination
of a Studebaker chassis and body with a Cadillac
engine. But the Doodelac is our own idea-nourished
by some suggestions from Ed Cornfield, Executive
Secretary of the IHFM-and stems from the thought
that we can start doodling on a piece of paper and
come up with just what we want in an automobile.
A few weeks ago Business Week carried an article
which showed conclusively that there was no such
thing as a "standard" automobile, each one being
practically a custom model made for the special requirements of the buyer. This is quite obvious to anyone who has ever bought a car or who has even read
any of the ads. When you get ready to sign on the
dotted line for a new jalopy you have the opportunity
of stating your preferences in a number of particulars
-color, second windshield wiper, backing light, power
steering, power brakes, power windows, power seat,
radio, heater·, rear seat speaker, white sidewalls, Hydramatic, overdrive, and-as some wags put itwheels, seats, engine, and so on. This is just what we
do when we go to our component-high-fidelity dealer
and select a home music system-we choose the things
we want.
12
Of course, for the economy minded (or economy
enforced) and for those who do not know how much
more enjoyment can be had from some of the refinements in an automobile, there is the stripped economy
model, equipped with only the barest minimum of
necessities. Such cars run, naturally, and even serve
their users' needs well enough, even though they do
not have the advantages we have come to enjoy and
expect. Since these economy models do not come in
the popular two-tone finishes, they are often referred
to as the "one-tone" models.
And this brings us to another similarity between
high fidelity and automobiles-for there are also" onetone" models in hi-fi. These are likely to be really
"one tone"-with juke-box bass booming at around
100 cps and with precious little below. It is easy, for
exampie, to use a loudspeaker with a relatively small
magnet-and consequently littl!il natural dampingand get an artificial bass which sounds real good to
ears accustomed to a $12.95 mantel radio-(the kind
that sell now for $39.95). Even the ads about these
"one-tone" packaged sets sound at least as good as
those about quality merchandise.
One we read recently deplores the do-it-yourself
trend with the suggestion that you shouldn't do it
yourself if you can get others to do it for you, though
this is not in the good old American tradition, to be
sure. The ad suggested that even the word screwdriver
has different connotations to different people.
We submit that some of the current hi-fi ads seem to
be the product of the Madison Avenue "screwdriver
mechanics' '-liquid screwdrivers, that is. Anyone can
call his product "hi-fi" since there are no industry
standards by which performance can be judged hi-fi
or not-just print it on the nameplate and the shipping box and you have it. Thanks to the component
high fidelity industry, the public has become conscious
of the terms" high fidelity" and" hi-fi," and in order
to sell at all any phonograph must be called hi-fi regardless of what it sounds like. Fortunately there are
plenty of people who can tell the difference simply by
listening, but it is not often that they have an opportunity of hearing both component-high-fidelity and
ready-built "packaged" hi-fi side by side, since these
are rarely sold by the same dealers. One doesn't go to
Aeolian-Skinner Organ Company to buy a mouth
organ.
Manufacturers of component high fidelity are either
too honest or too naive to foist some of the current
advertising effusions onto the public to sell their products, we are pleased to note. When you have a quality
product, you have only to state facts-when you have
a shoddy imitation of qua1ity you sell it with words,
not performance.
AUDIO
•
AUGUST, 1957
--#-1uxvalvE.
••• ••• ••••
•
••
•
•
the
pickup
with
••
•
••
•
•
•
•
•
• UNEQUALLED FLEXIBILITY
••
• SINGLE OR DOUBLE PLAY
•
•
•
I)
• STYLI EASILY REPLACED
•
•
•
• NEW ANTI-HUM DESIGN
•
••
• RUGGED CONSTRUCTION
••
The only pickup .•.
•
• • • • •• ••• • ••
••
•
••
••
you can custOIn tailor to fulfill
all requirelllents for optilll Ulll,
unequalled play-back perforlllance
of every record in your collection
ONLY THE FLUXVALVE OFFERS ALL
THESE SIGNIFICANT FEATURES:
H igh compliance with low vibrating mass ... unexcelleq. transient response ... fiat frequency response
well beyond both ends of audible frequency .. . uneq,ualled definition and clarity, each instrument or
voice is individually distinguishable .. . complete
absence of resonances in the audio frequency ... low
overall distortion . .. anti-hum design ... stylus
changing is easy; no tools .. . hermetically sealed
cartridge body.
. EXAMINE THESE
. EXCLUSIVE FEATURES:
half .mil single play
halfmil-1 mil double play
half lTIiI-2 '/2 mil double play
'-11 mil-2Y2 mil double play
..p lus. .1 mil single play
,
2Vx ,mil single play
,
Enjoy a new listening pleasure and experience . .. ask your dealer to demonstrate
the Fluxvalve . .. words cannot describe the difference . .. but you will hear it!
----- --- - - - - - - - - - - ------- - - - -- --- - - - - -- - -- - - - - - - - - - - - - - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - - -- - - - - - - - - -- - - ------_...
. --- ----------- - i- -- - -----------~
!, PIC K E R I N G
&
:
!protessional Audio Components
,
CO., INC.
~~m=
_ Cn); Ul£lJ.e
~/I . ~
/I
gtJt
0
P/7/M
VU/,n/
C E A
/I '- I
~
I
Demonstrated and sold by Leading Radib Parts Distributors everywhere, For the one nearest you and for detailed literature: write Dept. A·IS.
EXP·ORT:
AD.
A UR I EMA,
INC .• 89 BROAD ST .•
NEW Y OR K /
AUGUST, 1957
Y.
~/I ~U/ru..r
,L-/L!7.nAM':'!
uze.
/
:
.
•
N.
:,
CANADA: CHARLES W. POIN·T ON LTD .• 6
. ----- -- -------- - - --'- -------- -.--- ---~ --- ------ - --- -- -------- -- --- -- .:..------------------------------ - -------- -
AUDIO
N SID E .
ALCINA AVE., TORONTO
.'
... ------ --- --- ------- -~--.,---:-:---.
13
Electronic amplifier. First high-vacuum electronic amplifier.
Made possible long distance telephony and then opened the
way to radio broadcasting.
Wave filter. Precisely separates bands of frequencies. Provided major key to economical sharing of the same wires by
many voices or radio programs. Indispensable control tool in
radio, television and radar.
Negative feedback amplifier. Provides distortionless and
stable amplification. Made possible the enormous, precisely
controlled amplification needed in long distance telephone
calls. The principle is now basic in high-quality amplifiers for
radio, TV and high-fidelity reproduction.
Pacemakers in the
Quartz crystal. Standard super-accurate quartz crystal oscillator developed for frequency controls in radio telephony.
Has also become the standard control for clocks in world's
astronomical laboratories.
technology of our
electronic age
~J
~
Certain discoveries, inventions and
developments of Bell Telephone Laboratories have been truly epochal in
their effect upon the technology of
ou.r time. Each has come out of a single quest-a search for ways to make
telephony ever better. But many have
opened the way to exciting advances
in TV, movies, radio, horology, astronomy. Here are ten of Bell Laboratories'
contributions to the modern wo.r1d.
Coaxial cable system. Hollow tube with a central conductor
was developed to transmit hundreds of voices simultaneously.
Now also provides long distance carrier for TV in partnership
with microwave beams.
Transistor. Tiny solid-state device uses extremely small
amounts of power to amplify signals. Makes possible electronic
telephone switching and much smaller hearing aids, radios,
TV sets and electronic computers.
Dial system "brain and memory." Takes over your call
and sees that you are connected in the best and 'quickest way.
Newest example: Direct Distance Dialing from home telephones to any part of the nation.
Waveguide. Hollow conductor transmits high-frequency waves.
From this came the "pipe" circuits that are essential to radar
and very short-wave radio communications.
Microwaves. Bell Laboratories developed long distance microwave transmission. It operates by focusing radio beams
from station to station, carries cross-country telephony and TV.
Radio astronomy. This great new science began in the study
of radio interference at Bell Laboratories .. . with the tremendous discovery that radio waves emanate from the stars.
BELL TELEPHONE
LABORATORIES
@1
WORLD CENTER OF COMMUNICATIONS RESEARCH AND DEVELOPMENT. ..... ".:;:::-..-
High-Quality Treble Amplifier
Cdr. CHARLES
w.
HARRISON, JR., USN':'
The author describes a four-watt amplifier which employs a single-ended output stage
and which is inten~ed f.or u~e as a ~river for the tweeter of a two-way speaker syste~
for home use. This Unit will considerably decrease the cost of a two-amplifier system .
1. Intl'oduction
I
the writer described
a dual-channel playback system consisting of a dividing network and two
identical amplifiers for driving the bass
and treble sections of a dual loudspeaker.
This arrangement is economical when
speaker elements of approximately the
same efficiency are employed, as for example, horn-type speaker s for the reproduction of both the low and high
frequencies. When the bass section is
much less efficient than the treble system,
as will be the case when direct-radiator
dynamic, loudspeakers are used for bass
and a horn-type speaker for treble, it
becomes entirely feasib le to use amplifiers of considerably different power output ratings in a divided amplifier system . For example, if a direct-radiator
bass speaker, in the appropriate baffle,
has a conversion efficiency of 5 pel' cent,
and the high frequency drivel' with horn
has an efficiency of 50 p er cent, 40 watts
input to the woofer and 4 watts input to
the tweeter will result in the radiation
of 2 watts of acoustic power in each '
channel. One will be able to achieve lowfrequency/high-frequency balance2 under most circumstances, and simultaneously utilize the power capabilities of the
bass and treble amplifiers. As a practical
matter the propel' setting of the volume
controls on the amplifiers to obtain the
most pleasing response must be determined experimentally by conducting listening tests in the room in which the
dual loudspeaker is located.
The purpose of this note is to describe
a simple 4-watt single-ended amplifiel'
intended for use as a drivel' for treble
speakers, such as the Western E lectric
594A, Jim Lansing D-375, 01' Altec 288B,
when used in a home music r eproducing
system, or small auditorium. The fact
that the power output of the amplifier
N" A RECEN'], PAPER 1
* 1401 N . Pocomo7ce St " Arl'i ngton 5,
Vi1'ginia
1 Charles W . Harrison, Jr., " High·qual·
ity dual· channel amplifier," AUDIO, J anu·
ary, 1956.
2 Balauce between the low and high frequencies depends on such factors as the
directive properties of the speakers, crossover frequency, speaker locations, room
acoustics, and the spectral distribution of
the energy in the program material. Consideration of these factors may dictate different power ratio requirements for a given
system.
AUDIO
•
AUGUST , 1957
.002
6J7
16 ...
OUTPUT
INPUT
1~~
r-=-
40=
260 V
Fig . 1. Schemat ic wiring diagram of 4-watt treble amplifier.
cannot exceed 5 watts, regardless of the
freq uency and amplitude of the excitation voltage, insUl'es that the tweeter
diaphragm will not be fractured by the
ina dvertent application of low-frequency
sig'nals, 01' by the development of faults
in the treble amplifier.
The Amplifier
The amplifier is built around the Triad
HSM-79 hermetically sealed, high-fidelity output transformer. This transformer
has a 5000-ohm primary designed to
carry an unbalanced current of 40 rna,
and secondary impedances of 16, 8 and 4
ohms are available. The g uaranteed fre quency response is within 1 db from 50
cps to 25 kcs.3 The r esponse. is greatly
improved particularly at the high end of
the frequency spectrum, by the application of negative f eedback around the
3 Some readers may fe el that the lowfrequency response of the Triad HSM-79
transformer is inadequate. The fact that
t he primary winding carries unbalanced
d.c. makes it difficult to achieve high primary inductance. Thns one might anticipate degraded low-frequency response compared to the response of high-fide lity output
transformer types designed for pnsh-pu11
applications. If the amplifier is to be used
in the treble channel of a dual-channel
playback system, it is perfectly satisfactory
-and even desirable-for the frequency
response to begin falling off at approximately an octave below the crossover frequency. 'Phe "fusing" of the treble drivel'
is enhanced by a ro11off in the bass response of the amplifier.
transformer. Two tubes are used in the.
amplifier- a 6J7 followed by a 6V6. The
schematic is shown in F'ig. 1. Two feedback paths ar e employed-one from the
p late of the 6V6 to the cathode of the
6J7; the other path is from the secondary of the output transformer to the
cathode of the 6J7, These p aths are not
independent, i.e., changing the circuit
parameters in ene path changes the effective value of feedback into tke other
path.
Performance Data
The p erformance data p resented here
was obtained from measurements made
on an amplifier having circuit values
shown in Fig. 1, with the following exceptions: (a) The .02-t1.f input capacitor
was shoded. (b) A 270-ohm 2w resistor
was used in the cathode cir cuit of the
6V6 output tube in lieu of the 300-ohlll
2w resistor shown in tl,te drawing. The
measured grid bias was 12 volts, (c)
The interstage coupling capacitor was
0.06 !J.f instead of 0.1 !J.f as shown.
A 16-ohm resistor was used to load
the amplifier fo r all tests.
The component values employed in
the feedback paths result in appr oximately 20 db loss in gain compared to
the gain of the amplifier without feedback.
F 'igwre 2 is the. power CUl've of the
amplifier. It was obtained by adjusting
thE' inp'.lt signal voltage at each fre-
15
db
+2
+1
0
-1
-3
-4
-5
-6
-7
-8
"-
/.
/
-2
\
/
Fig . 2. Amplifier
power curve.
\
_\
I
watt except the cathode resistor in the
6V6 circuit. The outl'lut transformer
must be connected in the circuit as shown
to insure that the feedback is degenerative. Figur.e 3 shows the completed amplifier, and Fig. 4 shows the component
arrangement.
I
The p'o wer Supply
100
10
1000
10,000
100.000
FREQUENCY IN CPS
NOTE : 0 db CORRESPONDS TO 4.2 WATIS OUTPUT POWER.
Fig . 3. Photograph of completed amplifie r.
Many audio hobbyists possess a power
pack that may be used to power the
treble amplifier. The power supply described in a previous article l provides
plate and filament voltages for both thll
bass and treble amplifiers in the writer's
dual-channel playback system. A 10-watt
resistor of 750 to 1000 ohms, is required
to drop the p late voltage to the correct
value of 260 v. This resistor is shown
in Fig. 4. The plate current of the 6V6
does not vary more than 1 or 2 rna from
zei'o signal to maximum signal, so the
voltage regulation of the power supply
is not too important.
The power requirements of the treble
amplifier are 6.3 v.a.c. at 0.75 a, and
260 v.d.c. at 45 to 50 rna. The sche.matic
for a suitable, yet inexpensive power supply is given in Fig. 5. The transformer
should have minimum ratings of 300
v.d.c. at 60 rna; 6.3 v.a.c. at 1 a, and
5.0 v.a.c. at 2 a. A 5Z4 is employed as a
full-wave rectifier, and filtering is accomplished by use of a resistance-capacitance network. Such filters are recommended when the current drain does
not exceed 50 rna. When choosing a plate
transformer for use with RC filters it
is important to remember that the power
consumed in heating the filtering resistors must be provided by the transformer. If the power supply design is
not carefully executed a transformer of
(Contimted on page 44)
quency of measurement until barely visible waveform distortion occurred. The
power output was then computed at that
frequency. Thus Fig. 2 is in reality a
curve showing power output as a function of frequency for constant distortion. 0 db corresponds to the power
output of 4.2 watts. H is believed that
approximately 3 per cent harmonic distortion in the amplifier can be detected
by eye, when a good oscilloscope is used
for viewing the output wave shape.
When the input signal voltage is adjusted so that the amplifier delive.rs 2
watts at 1000 cps, the amplifier is fiat
from 30 cps to 80 kcs. It is down 2.5 db
at 20 cps and again at 100 kcs, tapering
off to - 8 db at 150 kcs and -12.5 db
at 200 kes .
The response of the amplifier to a
20,000-cps square wave is highly satisfactory; to a 10,000-cps square wave
the response is perfect.
Constructional Details
The amplifier is easily built on a
5" x 7" x:3" chassis. All resistors are 1
16
Fig . 4. Arrangement of components in the amplifier.
AUDIO
•
AUGUST, 1957
Equalizer Desi-gn
--1
NORMAN H. CROWHURsr::
In two parts-Part 1
Presenting a thorough derivation of the formulas for calculating equalizers of the type
commonly used in constant impedance circuits, ·but related to all audio applications.
llE;UE WAS A Tnf;;; when the addition
of an equalizer merely consisted of
r
inserting a .003-p.f capacitor in series
somewhere or putting a .00005-p.f capacitor in shunt and seeing if it improved
the reproduced sound. The result was
j udged by ear and if the improvement
did not satisfy, the decision was made
(A)
(8)
whether a larger or smaller cap-acitor
should be used in this position, and then
another value was tried. This cut-and- Fig . 1. Basic networks for step response .
try process continued until the resulting The componen t-:-inciicated as X may b e
either capacitance or inductance.
reproduction sounded acceptable. But
model'll standards have gotten a long
way from this indeterminate cut and try by each of the circuits shown in Fig. 1,
method. Nowadays we need to get a pre- and also show& -the reactance element to
cision into our equalizer design to corre- use to produ~ each kind of slope and
spond with the precision with which we the formulas for finding the reference
tailor an amplifier response to within frequenci::s
or f s'
plus or minus a fraction of a db throughThe simplest.,way of deriving the reout the audio spectrum.
sponse- charactel!istic uses one of these
Tailoring equalizer response to su ch turnover freqnenc:es, f 1 or f 9 ) as a referpre-cisiorr by th'e ' cut and try-meihod can
prove a very protracted process, so we
need a more direct method of design.
The formulas iRvolved in the basic_bu ifd~­
ing bricks of which equalizer circuits are
built, are not very complicated and are
given in f ull in the appendix to this
article. Four basic types of cir cuits will
be considered : (1), step circuits, sometimes called shelf circuits, which introduce a slope from one level to ~ariother;
(2), peak circuits,.:which introduce a rise--at one frequency and fall away symmetrically at both sides; (3), dip circuits, with a dip at one frequency, similarly symmetrical on both sides; and (4),
finally, a peaking circuit at the end of
the response curve, which marne use'(!
to maintain response in compensating
for a high-frequency or low-frequency
roll off. Each of these tYIl~s of circuit
is considered here in turn. \ .
,
=t
1:
ence, to derive the attenuation factor A
given by Eq. (1) in the appendix. This
producEs an a ttenuation response equation of the form given at (,2) in the appendix. This form is useful because it
can readily be converted into a chart for
computing the exact shape of such a
step response. Such a chart may take
the form of a universal graphical curve,
of which the one presented in an earlier
article! is an example, while many will
prefer the nomograph construction of
Pig. 3. While the latter presentation is
not so visual as the graphical form, it
is much quicker to use in plotting out
any p articular response curve required
which is t.he practical function of the
chart .
By using a different normalizing fre1 N. H . Crowhurst, "Prediction of audio
response." Eleot1'onio Engineering, July,
]952.
1
""o
i
~
11
"g
J:
~
~.
"-
db= 10 log10 K
Step Ci rcuits
_K
1
r;;
-IJ
- - - - - t - - - _______
This is by far the most useful building
block for most equalizers. Fig. 1 shows
Klh __- I
the basic step circuit arrangement using·
boxes to represent the reactances which
12
may be capacitors or inductances. UsuFREQUENCY - LOG SCALE
ally capacitors are used because they
avoid some of the t rouble that can occur
with the us.e of ind.u ctors. , F:igu,:e . 2 , Fig. 2 . .Essential dim.e ns.ions of a ' step response in terms of the ..circuit. constants_ The
sin'~11 figur.es::at the t9P indicate the... kin.d "of ~esponse given by each possible arrangeitl'e~tifies · the.; kind of response produced
* 150 47th Road, Whitestone 57, N . Y.
AUDIO
•
AUCUST, 1957
ment, togetbe'r with r.ea.ctance values ·· for. }I·. ahd ' f3 in each case. The large scale dia-.
gram shows the esserltial .atte nuation values in terms of K = 1 + (r/ R).
17
20
20
10
S
l
2
IS
Fig. 3. Nomogram for quick computation
of step response attenuation characteristic, normalized to either f. or fa.
.2
.4
.S
.6
.7
.8
.9
I
~
~
I
.9
.8
10
I
9
8
7
6;0
~
~
..J
~
S
4 I
~
~
UI
3
. UI
3e1)
UI
~
2i
a::
~
~
5
.7
~.6
i
.S
b
2~
'w
S
.4
~
3
r
::;)
~
.........
~
i
J.S
i
.3
.S
4
15
3
1.3
.1
2
10
25°
~
3
Q
~
2~
~=>
I.S
ZOO'tA
ISO~
IOO'tA
fo~
7'
60~
SO
4'~
~
. 3°
~
8.3
....'"
~
.s
fa '.
N
!l I
6
.I
t'
1.3
.I
. 10
quency for the response, 12 of Fig. 2, the
phase characteristic can be presented in
a similar universalized manner and such
a chart was included in the article referred to, while the nomograph of Fig.
4 gives a quicker method of accurate
computation .
The use of these .charts can .prove
somewhat protracted in finding the correct response to fit a given purpose. To
know whether a given set of values will
achieve the required equalization, it is
necessary to substitute these ,v.alues into
the appropriate equation given with Fig .
2, and then use the chart to plot out
the response. If the response does not
prove to be exactly what is required, the
values are adjusted and the response
replotted until a suitable one is found.
We still need a more direct method of
approach for precision equalization
work.
Equalizers are often needed, to produce a specific slope to compensate for
some other slope within a specific range
of frequencies. To aid in finding the best
step response to approach this, graphs
indicating the slope of step responses at
different points on their characteristics
will be helpful. Figure 5 gives data of
this nature plotted from the equations
developed in the appendix and includes
characteristics of the slope at the midpoin,t of the step network, the slope at
the. turnover point, the attenuation or
bl?ost at the turnover point (which never
quite reaches the ideal 3 db), and also
sOllJ.e details about the phase correction
intr.oduced by step networks.
Sometimes these networks are required
in feedback circuits as an aid to achieving stability, and the direct information
given by the data of Fig. 5 concerning
phase advance or delay produced by the
step network is an aid in finding suitable
values for feedback circuit design.
Sometimes a specified slope has to be
continued beyond the range which can be
achieved by a single step network. For
example: a wide range of 3-db-peroctave slope may be required. This would
have to be synthesized by a number of
step networks arranged so that their
maximum-slope points are, in this case,
3 db per octave and so spaced that one
takes over where the next one leaves off.
This kind .of slope synthesis can also be
quite protracted-even when one knows,
from the precise slope at midpoint, the
correct configuration to be used for each
step: there is still the problem of how
to space the steps over the frequency
band.
Fig. 4. Nomogram for quick computation
of step network phase response, normalized to f2•
AUDIO
•
AUCUST, 1957
VALUE
30
2
6
3
OF RATIO
K
5 6 7 8 9 10
4
From this the attenuation response is
derived:
.db l088 = 10 log,. A'
20
= 10 log,.
2S
5
20
4
«
"at ~
The ultimate step height is 20 log,. K,
where
sc:aleC
db/octavc at
?
K=1+a
scale B
ID
db
§"
§
lOS8
2
5
I
~ [10 IOg:_1~+_K_'-;;-X_"J (2a)
_~ 1+#
The phase response can be derived from
(1) as
db at~ ~
10
(9)
Substituting this into (2) gives the form:
15
.!!
[1 + (2a +a") 1:"x.] (8)
scale B
ax
dbfoctave at
~
!f
</>=tan-l 1 +(1+a)x'
scaleB
(4)
=tan-l (K-1)x
1+Kx'
(ia)
The variable x normalizes to one' turnover.
By writing
0
0
23
VALUE
4 5678910
1:.
OF RATIO ,R
y'=Kx"
20
(5)
the normalizing frequency for y is the
midpoint, f. (Fig. 2). With this reference,
the phase response can be written
Fig. 5. These graphs aid in selecting the right step response to fulfill specific requirements, without unnecessary plotting out of trial response characteristics.
The solution to this is given by the 50 and 150 cycles, the second step bedata in Fig. 6, which plots the frequency tween 360 and 1080 cycles, with a third
spacing between reference points on in- step at 2590 to 7770 cycles. These three
dividual step characteristics, and also the steps will practically cover the entire
frequency spacing between reference audio range with a slope of 3 db per
points on adjacent step components of a octave.
So far we have considered the basic
synthesis so as to cause the half-slope
points to blend and produce the best networks for step responses. Later we
possible approximation to a constant shall give methods of applying the basic
networks to practical circuit configuraslope over a wide range.
In the example quoted, the chart gives ' tions.
a value of 3 for the ratio K between the
ApPENDIX 1
design frequencies, fl and fa on the same
Using x to stand for f/f., where f. is
step network which means the value of
normalizing frequency at the lower
t·/ R must be 2 and the insertion loss will the
turnover of a low-frequency boost circuit,
be 9.5 db per step. The frequency ratio or f./f for a high-frequency boost circuit,
between successive steps requires to be the attenuation referred to the upper level
7.2 as given by Fig. 6. From this infor- 'is given by
A_1+ (1+a)#+jax
mation a whole succession of designs can
(1)
1+#
be quickly set out. For example the first
step design frequencies will be between where a is the ratio r/B (Fig. 1)
K-1
KI!.
.,
(4b)
1+y"
Substituting x = 1 into' (4a) gives the
</>=tan-1 - - x -"-
phase at frequencies f" f .. as:
K-1
+1
</>,. = tan-1 K
(40)
while for the mid-frequency f .. substituting
y = 1 into (4b) gives
K-1
</>.=tan-1 2KI!.
(4d)
Using the mid-level as an attenuation reference:
db = 10 log,.
[1 +K~"l-10
log,. K
1+L
K
= 10 log,.
KY']
[ 1K++ y'
(2b)
The midpoint is also the most useful reference for slope, because the curve is
symmetrical about this point. Using the
unit slope formula:
d log A' _
(K"-1)y'
(6)
d log x' - (K + y") (1 +Ky')
or, in db/octave, taking 3 as an approximation for 10 10g,. 2,
6(K" -1)y'
slope = (K + y') (1 + Ky') db/octave
./
4
6(E."-1)
6(K -1)
K + 1 db/octave
(8)
Slope at turnover points: y" = K,
3(K'-1)
slope = K' + 1 db/octave
(9)
./
slope = (K +1)"
./
Value of ratio K
for each step
3
FJ'aflcncy ratio
between steps.
V'
Attenuation at first turnover, or boost at
lower turnover, can be found by equating
x=1/K in (2a):
1/
2
(7)
Slope at midpoint: y = 1,
II
i
db=10 log,.
I/)
I
[1~~]
(10)
In slope synthesis, the half-slope point is
useful, this can be found by equating:
2(E." -1)y"
(K + y') (1 + Ky')
°1
2
3
4
5
Ratios
6
7 8 9 0
20
AUDIO
•
AUGUST, 1951
(11)
and then solving for y':
... = E." + 4K + 1 +
Fig. 6. These curves aid in synthesizing any desired slope over a wide range of frequencies. The curve at the right gives the ratio between points on the curve where
the slope falls to one half its maximum value at midpoint. ,
K -1
=K +1
"
2K
,
-
J"'[K'T>'O'-:-t-;4",.;K;-+:-17']";-"_-1
2K
(12)'
'\J '.
(To be concluded)
19
From the Archives of Bell Telephone Laboratories
Auditory Perspective
A quantitative study of the effectiveness of two- and three-channel stereo systems along with
various combinations 'of microphones and loudspeakers mixed in usual phantom circuits.
W. B. SNOW
T
of the
reproduction of music in auditory
perspective is the outcome of studies
carried on by the Laboratories over a
number of years. The word perspective
is, of course, taken over from a visual
phenomenon, and implies the recognition
of relative locations in space. Auditory
perspective thus means the ability to
judge the location and distance of sounds
by the ears. It might seem that the .reproduction of music would not be much
improved by this ability, but it has been
HE SUCCESSFUL ATTAINMENT
(Reprinted by permission from Bell LaboratoTY Record, Vol. 12, No.7, March,
1934.)
P!CK-UP ROOM
m·
1lI. JX.
11· V. D.
I. lY. W·
Mf
1
ROPH0
S
r;"
li
LOUD
~EAKERS
li
CURTAIN
AUDITORIUM
I
0
I
I
10
I
I
20 FEET
x
AVERAGE
LISTENER
POSITION
Fig. 1. For experimental purposes, pickup microphones were mounted in a
sound-proof room and connected by independent circuits to loudspeakers on the
stage of the auditorium • .
20
found by many actual tests that the ma- duce an effect substantially similar. An
jority of listeners recognize an appre- extensive series of tests was run at Bell
ciably enhanced value of the aesthetic Laboratories to determine what was posappeal if auditory perspective is present. sible in this direction. These experiments
One method of securing the sense of were performed with either two or three
localization for reproduced sounds is to channels since it is desirable to use as
pick up the source with two Inicrophones few channels as possible to produce the
located in the same relative positions to effect desired.
each other as are a person's ears. Then
In the experimental set-up, shown in
by providing a separate circuit for each Fig. 1, three microphones placed in an
microphone to two head receivers held acoustically treated room were connected
to the ears of a listener in a distant loca- by individual amplifier channels to three
tion, the directional and distance sense loudspeakers concealed behind a gauze
is completely secured. This "binaural" curtain in the auditorium. At a little less
reproduction has already been de- than three-quarters of the distance back
scribed.1 With this type of reproduction in the auditorium were seated a, group
the listener is to all intents and purposes of observers. Their average position is
transported to the position of the pick- indicated by a cross on the diagram.
up microphones, and hears exactly what Most of the observers had had no previhe would hear if he were stationed at ous experience with this type of reprothat place. The effects that can be pro- duction, and their only instructions were
ducedin this manner are startlingly to note on a sheet of paper containing
realistic, as visitors to the Bell System a line representing the curtain, the point
exhibit at the Century of Progress Ex- from which the sounds they heard seemed
position attested.
to come. The positions from which the
A binaural scheme for the reproduc- sounds actually originated are indicated
.
tion of music before large audiences, by Roman numerals.
however, would be very inconvenient.
Tests were carried out in this manner
Every seat in the auditorium would have for five different conditions. These were
to be equipped with a pair of head compared with each other and with a
phones, and in a hall of any size, the direct listening test in which the sounds
necessary wiring and its upkeep would originated on the stage in front of the
be high. It seemed well worth while, listeners. The connections of the microtherefore, to experiment with other meth- phones and loudspeakers for the five
ods of securing a siInilar effect.
schemes are shown at the left of Fig. 2.
It is obvious that when one listens In the first, three microphones and three
directly to music, such as a symphony loudspeakers were connected by indeorchestra, one hears sound that--at least pendent circuits. In the second, only two
originally-passes through the opening microphones and loudspeakers were embetween stage and auditorium. If this ployed but the two circuits were indespace were filled by an array of Inicro- pendent as before. The remaining three
phones, therefore, each of which was schemes employed various forms of couelectrically connected by an individual pling between loudspeakers or Inicrocircuit to a loudspeaker similarly placed phones. The third arrangement used
before an audience at a distant point,
three microphones but only two loudthe audience would then hear-assuming
speakers-the middle Inicrophone dividperfect transmission-exactly what they
would have, had they ooen listening ing its output equally between the two
directly. Such an arrangement would, loudspeakers. The fourth arrangement
of course, be impracticable, but it is was the inverse of the third j three loudquite conceivable' that a much smaller speakers received the output of two minumber of microphones, properly placed - crophones. The fifth scheme was a comand connected by individual circuits to bination of the third and fourth. Ala similar set of Icmdspeake1:$, -):night pro- though three microphones and three
loudspeakers were employed, the middle
1 Harvey Fleteher, / / An Aeoustieal illusion telephonieally aehieved." Reprinted in microphone and loudspeaker were coupled to the two side channels.
AUDIO, July, 1956.
AUDIO
•
AUGUST, 1957
The results obtained under these five
conditions, as well as those for direct listening, are indicated at the right side of
Fig. 2. The average judgment of the position of the sound is indicated by circles
identified by Arabic numerals, which
may be compared with the actual position indicated by Roman numerals. All
five alTangements give to some extent
both sidewise (angular) and depth localization, but the degree to which they correspond to the actual conditions differ.
Even with direct listening, the depth localization is distinctly inaccurate.
For the three-channel condition both
angular and depth localization is very
good although the positions at the. rear
of the stage seem nearer to the center
than they really are. The two-channel
condition gave slightly wider separation
for the rear positions, but on the other
hand the depth localization was not so
accurate. With the bridged central microphone, condition three, the apparent
width of the stage remained about the
same but the centered positions were
brought nearer the front. A bridged cen ter loudspeaker, condition foul', moved
back the apparent positions of the central sounds but narrowed the apparent
width of the stage. With center microphone and center loudspeaker both
bridged, the apparent width of stage was
considerably narrowed, although the
depth was somewhat improved. None of
the bridged conditions was thus as good
as the independent channel conditions,
and three channels were appreciably better than two.
The microphones on the stage receive
both direct and reflected or reverberant
sounds, and similarly the observers receive both direct and reverberant sound
from the loudspeakers. Experiment
showed that decreasing either the total
loudness or the amount of direct sound
relative to reverberant, gave the impression that the sound was moving back on
the stage. Depth localization is thus a
complicated function of loudness and
relative reverberation. In the two-channel reproduction, for example, the cen -
~
:.J
u
2
'"o
o
oJ
'"w>
oJ
-2
~
./
lZl. IX.
V -"2IIII . Il[.W.
o
NEAR E >
/'
,
9
-4
~
Z -8
LEFT~
20
03
[K]
CENTER 0
RIGHT~
Fig . 2. Five di ffere nt circuit arran gements of m icrop hon es and louds peake rs were
t ried an d t he loc a liz a tion o btain e d by t he liste ne r is indica ted
by circles id e nti by Ara b ic
f ie d
num erals.
09
5
6~
LS 0 2
04
01
lS
5
68 04
~2 03
SPEAKER
LINE
60 07
CURTAI N
LINE
~lS
90
07
01
<II
::lE:C~
z
«
o
w
J:
Q.
<II
~
a:
0
u
lS0 1 0 2
03
6 0 6q, 9
5 Q)4
::>
-
lS
0
7
0
::l!
...J
4
E o.!
03
5,~
09
08
07
01
,E .
m.
DIRE CT
LISTEN IN G
9
~O6~8
05
04
JI.
V · 05
03
Il[~4
07
ZS
. IX
lZl·
1.0 1°2
tel' positions seemed further back because the distance of the sound from the
microphones was greater, due to the lack
of a central microphone. Under these
conditions the ratio of direct to reverberant sound is decreased.
Angular localization on the other hand
was found to depend primarily on the
difference in loudness of the direct sound
reaching the two ears from the local
speakers. Reverberation played a minor
part. When one listens directly to a
sound the configuration of the head
causes the loudness and quality heard
by each ear to differ by amounts related
3
0
20
01
E
9
8 0° . 1llII
06
7 0 .=
to the angle from which the sound comes.
For speech the relationship between
loudness and direction is shown by Fig.
3. The ears distinguish between the front
and rear angles giving identical loudness
differences probably because of the quality differences. When the observer listens
to the acoustic perspective system, he
hears sounds from several sources all in
front of him and of like quality. Calculations show that when the outputs of
the loudspeakers differ, resultant loudness differences are produced in the ears.
If the ear always translates a given
(Continued on page 45)
~}.
I'--..
~ 1---'
II
.........-r----
,, ",
-8
0
AVERAGE APPARENT POSITION
WHEN REPRODUCED
TYPE OF
REPRODUCTION
FAR EAR
,,
o
0
"'i-
\,"'"
z
o
0
MICROPHONES
~
w
~
n.
m.
--I:
"
ill
~
a:
CALLER'S ACTUAL POSITIONS
ON PICK-UP STAGE
40
I
DIFFERE NCE
"
~~
---l ---- ... ... _60
80
100
,,
V
~'
,
",
120
140
160
180
20·
A NGLE IN DE GR EE S
Fig. 3 (l eft). Difference in loudness in t he two e ars fo r speech comi ng fr om var iou s di recti ons. Fig. 4 (righ t>. Cu rves of consta nt
distance ra t io to th e two mic rophon es b e co me curves of constan t a ngular locali za t ion to th e listener.
AUDIO
•
AUGUST, 1957
21
Understanding Intermodulation
Distortion
I
MANNIE HOROWITZ*
The author explains the meaning of the term "intermodulation distortion,"
and describes methods of measuring it. Anyone comparing amplifier specifications is likely to encounter the term, and many want to know what it means.
when a music lover
ip
referred to high .fidelity, he wonld
8ma.----r---.---""T
discuss the frequency response of his
amplifier and the associated equipment. ::I---+-~'T\---Just after the end of the war, high
fidelity achieved a broader meaning. The
frequency response was still important.
Harmonic distortion was, however, the
:
I SINE WAVE FLATTeNS OUT
significant factor in determining how
I
I AND DISTORTS H~
good an amplifier really was.
I
I
Amplifier designers were not satisfied
I
I
with this for long. They found that there
I
I
was little correlation between frequency
I
response, harmo:nic distortion, and the
listener's approval or disapproval of a
particular high fidelity setup.
Fig. 2. A sine wave applied to a nonSome of the experts turned then to linear portion of the tube characteristic.
phase distortion. This type of distortion
exists when it takes longer for an audio tion, 1M is due to the nonlinear characsignal of one frequency to pass through teristics of the vacuum tube. This nonan amplifier than a signal of another linearity is shown by the curves which
audio frequency. It waS soon found that describe the operation of these tubes. If
this type of distortion had to be ex- a curve for the 1~AT7 were plotted, astremely bad to be discernible during the suming a load resistor of 30,000 ohms
in the plate, the resultant nonlinearity
playing of musical passages.
It was soon found that intermodulation distortion (abbreviated 1M) was
closely related to the degree of unpleasantness of sound reproduction to the
8ma
human ear. Various methods were devised to measure the 1M distortion factor
in amplifiers, Acceptable standards of
measurement were set up by at least one
organization~the Society of Motion Picture and Television Engineers.
N PRE-WAR DAYS,
,- :--~-- ,:~~~~~J
)
Fig. 3. Wave form of a modulated signal.
wonld be obvious, as in Fig. 1. It can be
seen that a change of - 2 volts from the
operating point, - 3 v., to - 5 v.in grid
potential causes a change or 2.4 ma in
plate current, while a change from - 3 v.
to -1 v. causes a plate-current change
of 2.7 mao If the curve were linear,
a grid voltage change of 2 volts either
way would indicate a plate current
change of 2.7 ma either way. If a 4-volt
peak.to-peak sine-wave signal were ap-
High frequency superimposed an
low frequency at tube's output.
Non-Linear Tube Characteristics
Just as in the case of harmonic distor-
* 945
-I,
E. 26th St., Brooklyn 10, N. Y.
High frequency superimposed ...... _...,..__-...:...
on low frequency at tube
input
PLATE CURRENT (ip>
./
~~
-S
~
-4
6ma
Sma
4ma
/"
CURVED
PORTION
-6
/
7mo
3ma
/"
2m..
--
~nnnnOonf\oonooonnOoono6
. VV~VVVVOllOOOUVVVVVOUUOij
Resulting high-frequency amplitude variation
due to modulation by low frequency.
lma
-3
-2
-1
0
+1
Fig. 1. Typical grid-voltage/plate-current
characteristic curve. A plate load resistance of 30,000 ohm,s and a supply of
300 volts is assumed for the 12AT7.
22
--
Fig. 4. Result of feeding two signals of different amplitude to the curved portion
of the 12AT7 curve.
AUDIO
eAUGUST, 1957
PATENTED DIFFUSICONE PRINCIPLE.
Available only on University Diffaxials. Mid and high
frequencies are extended with remarkable efficiency
through coaxial dual horn loading at the apex of the
loudspeaker cone. A radial projector combined with
aperture diffraction provides uniform, wide-angle dispersion, assuring full fidelity no matter where off speaker
axis you may be listening.
Q
1 1 ',
\,
•
;
j
EXCLUSIVE BI-SECTIONAL CONSTRUCTION
Typical of University's advanced design and fabrication
techniques is the unique bi-sectional construction of
completely independent basket and magnet assemblies.
This results in a precision product-vibration and shockproof in operation, built for trouble-free long life.
To insure valid statistics, this tabulation covers the .largest selling brands,
based on a four-year survey (April 1953 to March 1957) of classified and
"Swap or Sell" ads for used high fidelity loudspeakers. All ads authenticated
as placed by private individuals in Audio, High Fidelity and Music At Home
PERCENTAGE OF TOTAL INSERTIONS
SPEAKER "A"
SPEAKER "8"
46Y2%
23~%
SPEAKER
"c"
16~%
UNIVERSITY
13%'
PATENTED "RECIPROCATING FLARE" DESIGN
On all University tweeters the compression driver is
'c oupled to a "reciprocating flare" horn designed to pro\ vide maximum uniformity of wide-angle dispersion in the
horizontal plane with optimum vertical coverage. This
is the greatest single advance in wide-angle horn development in over a decade.
.
CEHTtRIHC
o".t--- - - ,
CROSSOVER NETWORK
,o.po"",,,---,
_ - -'R"'PI'"",,", FlAReS-
OAIVER tOR TWttTtR
Fewest number of ads offer University equipment
••• outstanding testimonial of user satisfaction.
OUST COy", _ _~
a:---SM""RaASKO
WOOfER VOICE ,""._ _ _..J
We have always believed that the tremendous volume of University speakers
sold in the past to hi-fi enthusiasts attested to the genuine listening satisfaction
designed into all our products.
We think that all legitimate hi-fi loudspeakers sound pleasing, but the
acid test of listening satisfaction is a speaker's "staying power". Does it grow
with your hi-fi tastes, continue to please year after year . .. or is it obsolete
before its time ... ready for swap, sale or discard?
Yes, in the "Swap or Sell" columns of the leading audiophile magazines,
you soon know which of the prominent brands of loudspeakers readers outgrow ... and, by the absence oj such ads, which of these leading loudspeakers
remain in the home!
The record speaks for itself. This accurate survey, taken over a span of
four years, shows that speaker "B" has almost 50% more "for s~le" listings
than University ... while speaker "A" is offered more than three times as
often! Here is indisputable unsolicited testimony from average hi-fi users
themselves that University stays sold, continues to serve year after year as a
source of rich musical pleasure.
University offers the largest selection of speakers and components to meet every size and budget requirement
LISTEN
UNIVERSITY LOUDSPEAKERS,
TRUE THRU-THE-AXIS DESIGN
~ thru-the-axis design, the tweeter driver unit is
fitted to the "reciprocating flare" horn thru the cenler
of the woofer magnet assembly. Only with this thruthe-axis design is it possible to project high freq uencies
thru a horn of scientific formula-correct length aqd configuration ... and thus achieve highest efficiency, lowest
~istortion and uniform wide-angle treble reproduction.
MAXIMUM COMPONENT FLEXIB~LlTY
To meet the ever varying technical needs of expanding
aspirations and improvements, University components
are designed to provide a maximum of application and
operational flexibility, e.g.: woofers with dual impedance
voice coils, networks and filters to match all popular impedances and crossover frequencies, speakers having
adjustable response devices, etc. Therefore • .•
,
$TARTt"
.
... . . . .+-----.- .
ME£f!It
,.;:....----+-----
-
i ~'
f
WOOfER
GENUINE PROGRESSIVE SPEAKER EXPANSION
The "Master Blueprint" that prevents your speaker
from becoming obsolete, because you can improve without
discarding existing speakers or systems ! You choose from
literally dozens of different starter speaker set-ups to
suit your present taste and purse. Then, when and as
you wish, you integrate these components into tomorrow's
magnificent deluxe system .. ,safeguarded by unmatched
engineering lIexibility and variety that makes "step-bystep" improvement a wonderful reality.
The.e arejuat afeuJ of the
rea.on. why Uni11er.ityauuTs,
you .uperior .ound that live.
and la.t. through the ;yea ...
A. other .atU,fied
purcha.er. knoUl •••
you might .pend mOTe~
but you can't equal Univer.ity.
plied to the grid circuit of this tube, one
half would be amplified more than the
other half, as shown in Pig. 2. This distortion of the original shape of the wave
of this signal is due to the nonlinear
characteristic of the tube.
Harmonic Distortion
"'::JII...pw ; ,;,o'IOok to
ELGIN for
research, design and
manufacturing leadership
American's FULL VISION-FULL
SOll..ND audio equipment now carnes
,•..t.o.-.you ffom.lilgin! Warehouse and service "rac'n , ies are being maintained In
,c-Galifornta, of course; but manufacturingand product development have been
moved"to'-Elgin to work hand-In-glove
with Elgin's well known stylin{j and electropics research ex~erts. You can expect
_ the' :besl , .• In appearance and perfor,mance. . . . f~om Ameri<ft\ln Mlero- .....
phones.
J
Does your equipment ,require a specially
••"designed microphone1 AmeFican Is now
•better equipped than ever to help you I
ft
--~
~
MirJuJpltmte
tor e\lery use!
FOR BROADCAST QUALITY
1. DR330 Cardioid Dynamic and Ribbon
Microphone meets strictest ",equirements of tv-radio broadca,sting and
motion pictures.
2. Presidential Series Dynamic OmniDirectionaf Microphone is rugged, compact, quickly converts to 6 oz. hand
microphone.
FOR RECORDING AND!/'
GENERAL P. A. USE .
.
3. 022 Dynamic Omni-Dir.ectional Microphone is a beauty queen-a,nd dependable to'o. Quickly converts to hand use.
FOR T'APE RECORDER'S
4. Versatile microphone is dllslgned for
hand or aesk use, weighs only 2 ounces,
y~t gives outstanding perfor"!ance.
FOR SOUND-POWEREq
TELEPHONES
5. No external power source required
for this lightweight, sensitive unit.
__" ___ ,_. Rugged and extremely versatile.
FOR RUGGED, DEP-ENDABLE _
OUTDOOR MICROPHONES
'
6. A mobile microphone that resists
moisture. Ideal for ship-ta-shore and
aircraft installation. liIigh output, shock
resistance.
_EL.GIN NATIONAL WATC.H COMPANY
107 National Street. Elgin, illinois
'.
~.
-,
,
~,
l
i I
!
24
A wave of any shape-square, sawtooth, or even the distorted wave due
to the nonlinearity of the tube characteristic-is made up of the sum of many
sine waves. The distorted wave above
contains not only its original frequency,
known as the fundamental, but also numerical multiples of that frequency,
which are the harmonics. Thus if a 350cps wave were somehow distorted, it
would consist not only of the fundamental 350-cps wave, but also of components
of 700, 1050, 1400 cps, and so on. These
added frequencies, referred to as the
second, third, and fourth harmonics respectively, usually have smaller amplitudes than the fundamental. Adding all
these harmonics together, in the proper
amplitude proportion, will give the original distorted waveform.
A-pure -siJ;le 'oVa-ve-consists 'Only 'Of -the
fundamental, with no harmonics. Therefore it is said to have 0 per cent harmonic distortion. A distorted sine wave
contains a certain amount of these harmonics. The percentage of harmonics in
any wave determines the harmonic distortion, which is expressed in per cent.
Obviously, an amplifier with a minimum
of added harmonics due to nonlinearity
is preferred to one with a large number
of these generated components. Since
these harmonics were not present in the
original sine wave fed into the unit, it
is undesirable for an amplifier to create
them for the finished output.
Modulation
To the radio man, modulation is not a
new concept. The radio station sends out
a modulated signal (Fig. 3).
When an amplitude-modulated signal
is analyzed mathematically, it can be
seen that it consists of a high-frequency
carrier, such as 1,000,000 cps with an
audio signal, such as 400 cps, changing
the strength or amplitude of this carrier.
The result is a 1,000,000-cps wave varying 400 times a second in amplitude.
When the variation of the 400-cps is
great in amplitude, the peaks of the
1,000,000-cps carrier are greater; when
the 400-cps modulating signal is low in
amplitude, the carrier varies to a smaller
degree. This is the method of transmitting audio waves by radio through the
use of high-frequency carriers.
It can also be found that there are new
freq uencies created due to this variation.
Not only are the 1,000,000 cps and the
400 cps being transmitted, but there are
also sum and difference freq uencies present. Thus, due to this modulation, four
frequencies are present-1,000,000, 400,
1,000,400, and 999,600 cps. These latter
AUDIO
•
AUGUST, 1957
two frequencies are known as the side-.
bands.
This same principle of modulation
with sidebands is once again used in
every superheterodyne radio r eceiver.
The 10'00 kilocycles (1,000,000 cps = 1000
kilocycles) arriving from the radio station is mixed with 1455 kilocycles (kc)
created by the local oscillator in the radio. The result is the creation of the sum
frequency, 2455 kc, and the difference
frequency, 455 kc. Only the 455-kc sideband is amplified by the i.f. amplifier
with the 2455-kc sideband being discarded. This process of mixing of the
two signals by the first detector in the
radio is accomplished because of the
nonlinear action of this first tube. If tbis
tube were perfectly linear as far as its
input voltage-output current characteristics were concerned, tbere would be no
mixing and no 455-kc sideband.
.8l?cfi
·'Y
Ol) IYf&.
~
you
peak performance
hifJh 'fidelity at Low cost
Intermodulation Distortion
Extending this theory of modulation
to audio equipment, the mechanics of
intermodulation distortion become obvious.
In music, there is always more than
one frequency present. Assume in the
simplest case, that there are only two frequencies available-IOO-cps and 5000cps. If the ampli.fj.er were perfectly linear, there would be only two fre quencies
coming out of the unit-IOO and 5000
cps-neither one of which would be distOlted or mixed in any fashion. How.ever, if the amplifier were not perfectly
linear-as is usually\. the case-the 100
cps and the 5000' ep s·would mix, rtlodulate each other, and there would be the
addition of the sum and difference frequencies, namely 51,00 cps and 4900 cps.
The amount of these .§um and. diffcl'- --'
ence frequencies . present would constitute the percentage of intermodulatioil
distortion.
However, this distortion goes one step
further. Since the amplifier is non-linear,
there is also harmonic distortion present .
Thus not only are there 100 cps and its
harmonics such as 200, 300, and so on;
not only are there 5000 cps and its harmonics such as 10,000, 15,000, and so on;
but there are also the sum and difference
frequencies of these harmonics present
to add more to the intermodulation distortion.
This process fin ally ends with the side
bands; their harmonics and side bands,
and the harmonics and sidebands of every conceivable combination outlined.
The intermodulation distortion is a
check on the percentage of all these undesirable frequencies present in the output of an amplifier due to the existence
of the two original signal frequencies.
This is not as unwieldy as it might
originally, seem. The higher harmonics
usually have small amplitudes and may
be considered negligible. This by itself
(Continued on page 42 )
AUDIO
•
AUGUST, 1957
Traditionai Pilot engineering and quality assure optimum
pe ormance. All Pilot tuners feature Beacon tuning for
pr. e station selection. All Pilot tuners are also f~l1y
s ' ed to conform with FCC radiation specifications.
J
K
FA-550 FJ'vl-AM
Has tuned RF stage and dual cascade limiter-discriminator FM circuit for maximum
sensitivitYi - perfect quieting even with
fringe signals; AFC with disabling switch;
10 KC filter for AM; . lIywheel tuning ; builtin FM and AM antennas. Features preampaudio control with five input channels; humfree DC on tube heaters; tape head and phono
inputs with separate equalization; bass and
treble controls; separate cathode follower
outputs for tape recorder and power amplifier. Housed in handsome enclosure finished
in brushed brass and burgundy.
Dimensions: 4%,"h x 14lj2-"w x 10%,"d.
$159.50 Complete
FA-540 FM-AM
Has tuned RF stage for high sensitivityperfect quieting even with fringe signals;
AFC with disabling switch 10KC filter for
AM; cathode follower output; phono and
auxiliary inputs; flywheel tuning; built-in
FM and AM antennas. Housed in handsome
enclosure finished in brushed brass and
burgundy.
Dimensions: 4%,"h x 13"w x 8%,"d.
$109.50 Complete
FM-530 FM Only
Has tuned RF stage for high sensitivityperfect quieting even with "ft:inge signals;
AFC with disabling switch; cathode follower
output; phono and auxiliary inputs; lIywheel
tuning; built-in !1ntenna. Housed in handsome enclosure finished in brushed brass and
burgundy.-·
Dimensions: 4%,"h x 13"w x 8%"d.
$89.50 Complete
Make your own performance test of these tuners at-YE>ur Pilot dealer.
For complete specifications, write to Dept. AW-8
~.
N EWP ROD U C T S
• Heathkit 7o-Watt AmpUfier. Power to
spare is inherent in this new amplifier
which virtually " loafs" along at normal
listening levels. Design features include
6550 output tubes and a special Peerless
output transformer for minimum distortion and maximum stability. The power
supply incorporates silicon-diode rectifiers.
to 14,000 cps. The CA-13 (illustrated) is a
self-powered recording amplifier and playback preamp. It incorporates an illuminated VU meter. The CA-15 is a stereophonic dual channel playback preamp with
separate equalization for each channel. For
complete details and technical specifications write The Pentron Corporation, 777
H-3
S. Tripp Ave., Chicago 2, Ill.
high-impact plastic. Leading the new line
is a bass-reflex enclosure which replaces
one standard aco ustica l tile when u sed in
ceil ing instaUations. The unit features a
"Spiral Sound" faceplate which incorporates directional ports to achieve 360·
dispersion. Designed to handle an 8-ln.
• Tandberg' Corner Speaker System. Exceptionally compact in design, the new
Model 165BK Tandberg speaker system incorporates an 8-in. dual-cone speaker with
speaker, the baffle may be installed without the use of extra furring or blocking.
Complete literature covering the Fourjay
line is availab le upon request.
H-G
A calibrated control varies the damping
factor from 0.5 to 12 at all o utput taps.
A quick-change plug selects 4, 8, and 16
ohms, or 70-volt, output and the correct
feedback resistance for any desired conditions. A built-in meter reads plate current
for balancing the output tubes. For full
technical specifications of the Model W-6M
amplifier kit write The Heath Company,
Benton Harbor, Mich.
H-l
• Stereo Listening' Chair. Entirely unique
is a chair designed essentially for listening to stereophonic music which has been
introduced by Stereo Products Co., Severna
Park, Md. Resembling a conventional wingback seat in appearance, the chair has a
loudspeaker built into each wing. The effect on the listener is closely akin to that
.• "D1,1st Bug''' Becord Cleaner. The "Dust
Bug" is an assemb ly consisting of a lightweight plastic arm terminating in a small
brush of Nyl on bristles, each of which
is pointed so that the bottom of record
grooves may be thoroughly explored. The
brist les a lso serve to track the arm across
the record. A cylindrical plush pad is situated immediately behind the brush and
serves to collect the dust particles which
are loosened. The device is placed on the
record just before the pickup is lowered
and cleans the record as it is played.
Mounting of the arm is accomplished by
means of a suction cup which is attached
to the turntable base. Electro-Sonic Laboratories, Inc., 35- 54 36th St., Long Island
City 6, N. Y.
H-2
• Pentron Custom Tape Compone·n ts. Consisting of three tape transport mechanisms, three preamplifiers, and newly-designed 4-cha nnel mixer, the new Pentron
line of tape recording components permits
more than ten combinations for recording and pJaybacl<. These combinations inc l!Jde monau!'al and stereophonjc operation ,
with a cholCe of stacked or staggered
hea?s. Fea tures of the transports include
a s !ng le rotary control for all functions,
rapId speed change for either 7.5 01' 3 75
ips operation, and automatic self-energ'izing differential braking. Flutter is under
0.4 per cent. Finished in harmonizing gray
and gold, the mechanisms may be operated
either horizontally or vertically. The CA-11
p r eamplifier is a self-powered tape playback unit with frequency response of 40
built-in crossover networlc Enclosed in a
4-cu.-ft. cabinet, the entire assembly is
so light in weight that it can easily be
mounted at ceiling level. Availab le in handI'ubbed Norwegian mahogany, the enclosure measures 40"h x 21"w x 9 % "d. The
speaker is rated at 10 watts. Introduced
by Tandberg. the system is distributed in
the United States by Reeves Equipment
Corp., 10 E. 52nd St., New York City, N. Y.
H-4
• ViJrlng' Back-Mounted Tape Units. A
number of improvements a re incorporated
in the lin e of Viking tape tra nsports
and recording preamplifiers, recently announced as available in rack-mounted mode ls for professiona l a nd industrial applica-
• Transistorized Audio Control. Novel in
both engineering and mechanical design
th~ '''Transamp'' meets the most exacting
cntena for a preamp-control unit. Both
low and high, input signals are fed into
specially se lected low -n oise transistors. resulting in a signal-to-noise ratio which is
exceptionally high. Two triode stages fol-
tions. The transport is floated on rubber
shock mounts in a s t andard 10% X 19 ins.
rack panel. Of principal interest to commercial users is the 75P (half-track p layback only), 75R (half- tra ck er ase-record),
and 75RM (half - track erase-record-m oni tor). Also available are the 75B equipped
With. st~ggered heads for data recording
appllcatlons, and transports equipped with
f ull-track heads for broadcast use. The
Viking RP61-VU recording and playback
preamp (illustrated) is also supplied for
rack mounting, and is eq uip ped with a VU
meter in place of the magic-eye indicator
on the standard model. Full information
will be supplied upon request to Viking of
Minneapolis, 9600 Aldrich Avenue South,
Minneapolis 20, Minn.
H-5
• Plastic Speaker Ba.files. A new company,
Fourjay Industries, 2360 W. Dorothy Lane,
Dayton 9, Ohio, has entered the field of
low-level sound baffles with a complete
line of original designs, constructed of
26
achieved while listening to stereo music
with headphones. Music may be p layed
from any stereo playback machine. Loudness may be set to any reasonable level
wi~hout disturbing others in the room. A
SWitch mounted on the back of the cha ir
can be used to convert it to monaural listening when desired.
H-7
low which, by means of individual feedback loops, keep distortion and hum at an
absolute minimum, and provide additional
gain and tone control features. The use
of transistors permits miniaturization of
the Transamp, the entire assembly being
mo unted on a chassis which measures only
8"1 x 5"d x 2%,"h. Six separate inputs are
selectable by means of a panel-mounted
rotary sw itch. Controls include infinitely
variable compensation, gain control, record
equalization, and rumble and noise filters.
Full information will be supplied on re-
AUDIO
•
AUGUST, 1957
quest by Mad ison Field ing Corporation,
863 Madison St., Brooklyn 21, N . Y. 1[-8
• FUter Design Kit. Designers of a u dio
devices will fi nd man y u ses fo r the Filtorpac, a k it which offers t h e user detailed
fi lter data as well as a set of 18 high " Q "
toroida l inductors w h ich can be q u ickly assemb le d into a ll combinations of high, l ow,
band-pass, or b a nd-re jection filters. The
hear the music
not the speaker • •• •
inductors are encased in p lastic for r u ggedness and are provided with single -screw
mounting a nd t u rret term inals for maxim u m convenience in rapid assemb ly and
disassemb ly of test setups. The F il torpac:
fu lfi lls t h e need for a convenient and economical met hod of rapidly design ing and
bench testing prototype filters, for making
temporary fi lters for u se in laboratory
work, and for teaching the princip les of
e lectronic fi lters in school laboratories.
Manufactured by Torocoil, 2615 Bristol
Roa d, Col u mbus 21, Ohio.
1[-9
NEW LITERATURE
• Belden Manufa cturing Company, Ch icago 80, Ill., is releasing a new electronic
wire and cabl e cat a log. Catal og # 857 contains many addition s to the Bel den line, inc luding new a u dio cables, new microphone
cables, new hook-u p wire conforming to
MIL spec. 1 6878-B, and a variety of other
cab le types. For q u ick reference, wires and
cab les are grou ped according to use and
application.
X - IO
It is interesting to note that women are more
. sensitive than men to overtones in the higher
ranges. If your present music system includes
a dynamic tweeter, the resultant distortion
of these overtones may well be the cause of
your wife's complaints about the "shrillness"
or "loudness" of your music system ,
• Reeves Soundcra.ft Corpora tion, 10 East
52nd st., New York 22, N. Y. has just anno unced a free new pamphlet which discusses an often-negl ected factor in successful home recording-"How to Choose
the Right Recording T ape." This illustrated brochu re offers general information
on magnetic recor ding tape, recording
ch a r acteristics, a n d the elements which
govern t h e physical characteristics of the
produ ct. It a l so describes the individual
r equirements whi ch shoul d be consi d ered
in the choice of a recording tape. Permanence, longer p lay, dimensional stabil ity,
a nd economy are a ll ' features of the five
Soundcraft tapes.
I [ ·-11
The fact that the JansZen lets you hear the
music and 'not-the spea-ker, eliminating
exaggerated and distorted highs, solves the
problem for the sensitive listener. The key
to JansZen's achievement is four electrostatic
radiators, each of which is a virtually massless,
stretched diaphragm driven over its entire
surface by an electrostatic field, The result is
completely uncolored sound for the first
time in speaker development.
• Techniques Inc., 52 Jackson Ave .. Hack ensack, N. J .. h as available a printed bulletin on S u pracote #3, an improved screen
r esist for printed circuits. Th e materia l is
d es'gned to withstand the action of alkal in e clean ing and p lating baths without
lifting, pitting or underc utting. Sha rpn ess
a nd detail of patte rn field laid d own compa re favorably with direct photogra nhic
process.
1[- 12
• Ohmite M a nufa cturing Compa.ny, 3634
HowR.,·d St.. Skokie, 111 .. in Bu lletin 148B
describ es two incredib ly small "Tan-OMite" Series TW capacitors. The bu ll etin
alsn revi ews the new expanded line ot TanO-Mite units, g ives the m aximum canacit a nce and volta ge r a ting for each of six
case sizes. and lists val u es avail'lble from
stock. Copy of Bulletin 148 will be mailed
uprll1 written requ es t.
1[- 13
• Cine·m a. Engineering, D ivisi on Aer ovox
Col"t)oration. 1100 Chestnu t St., Burbank.
Calif.. h as just issued a new 16-page cata109" tit led "Audio Frequency Eq u alizers."
with product illustrations and two dozen
c harts showing resprmse characteristics.
variab le equalizer diagrams, and oth er
per tinent data. T he Cinema units nrovide
standard networks which, in simplified a n d
flexib le arran gements, may' be used to
build u p a lmost any type of audio freouencv respon se ch aracteristic. A unique
deviation from t h e u sual catal Og" style Is
the inclusion of eight case studies w h ich
describe probl ems and their sol utions as
e ncountered in actual field exper ience. Requ"sts for copies of this catalog should be
addressed to the attention of Mr. James L.
F o u ch .
1[-14
AUDIO
•
AUGUST, 1957
Write for literature' and the name of yourm earest dealer
PRODUCT OF
NESHAMINY ELECTRPNIC CORP.,
NESHAMINY, PA.
Export Division: 25 Wor! en Street, N. Y,c. 7. Cable: Simontrice, N. Y.
27
EDWARD TATNALL CANBY *
STEREO TAPES
Menotti: Sebastian Ballet Suite. Members
NBC Symphony, Stokowski.
RCA Victor CCS-29
Stereo Rating: 5
It is singularly fitting that this superb
"hi-fi" stereo tape should be conducted by the
old Maestro himself, the man who conducted
the very first stereo or chestra a quarter century ago, as recounted in AUDIO for June of
this year.
.
We'U let pass the slight confusion over
nomenclature here--the music is for a regularsized orchestra and the "members" of the NBC
must have constituted a Committee of the
Whole--aU the members; also, the NBC Symphony has been the Symphony of the Air now
for some time. Name-orchestra or no, this
group plays superbly under old man Stokowsky
who remains, when he wants to be, one of the
finest conductorial technicians we've had. And
t he stereo effect-phew, it's up to all Stokowsky-based expectations.
This is really stereo hi-fi! That is, it is an
exaggeration of stereo, but an effective one.
The pickup is closer, sharper, than in the
Reiner-Chicago stereos, the right-left separation
more definite and pronounced, the fi of the
individual instruments and groups ultra-ultra.
Bu t RCA hasn't forgotten the all-essential Ii veness . The huge space here is even bigger than
the Reiner one,· ·encompassing all the instru.
ments in its golden liveness so that they really
seem part of one big ensemble, in that space,
no matter how closely they are miked.
It is quite a feat thus to combine sharp,
close, hi-fi .miking in stereo with a real over-all
space-sense. Too often, close miking simply
puts the individual instrument or voice right
in your speaker box, only a few feet away, remOving its sound entirely from the recreated
space beyond a nd between speakers. That's not
good--especially when some sounds are inside
your speaker box while others, paradOld.cally,
seem off in space. You can work up a very
confusing sort of effect this way, for if part of
a n orchestra is imagined out in front in a concert hall, you can't very well have part of t he
instruments appear five or six feet away from
you in what seems to be a nearby seat! (If
it's a church, then some of the choir seems to
have strayed ou t into adjacent 'pews n ext to
you.)
You won't find any such inconsistency in
this RCA job, though you will find the ultrawell' defined highs and the big "crump" to the
bass that is popular in the snazziest monaural
hi-fi recordings, such as Mercury's "Living
Presence" jobs. Everybody, every instrument
here, is right out in that big, golden live ness
along with the rest of the orchestra.
The Menotti score, an early ballet (1944) is
a tine stereo piece, full of soloistic color effects,
clearly and transparently orchestrated. It's
sharp and modern, but full of sweet sentiment
too. The waltz-like music in the middle is particularly good in stereo. And as 1 say, the
playing is wonderfully alive, plastic and expressive. Good old Stoky.
"180 Greenwich St., New York 1 4, N. Y.
28
STEREO RATING.
Mr. Canby rates stereo tapes on
a scale from 1 to 5 (5 being the
highest value) as to specific stereo
effectiveness, over and above the
ger.le r.al v.alues of recording and performance as heard in comparable
monaural reproduction.
The rating is personal, includes
both musical and technical features
that contribute to stereo value. It is
designed to measure the stereo
worth of the recording in terms of
the greater cost of stereo tapes and
of stereo playback equipment.
All tapes were reviewed in the
stacked {in-line} form. Some, but
not all, are available for staggered
heads as well.
A Concert by the Oberlin College Choir.
Robt. Fountain, conductor.
Livingston 714-BN
Stereo Rating: 3-5
Choral music is a natural for stereo, and it
isn't easy to go wrong, so gracefully does the
choral sound project with two·cbannel help.
This excellent and accurate young people's
group sings in a somewh at too dead space-too dead, that is, for maximum stereo advantage over the equivalent monaural-but
even so it makes an excellent record, the stereo
sound more natural and seemingly less distorted and "squeezed" than the same via one
channel. In the Bach Motet, which is sung by
a double choir, the stereo advantage suddenly
goes 'way up--for purely musical reasons. The I
slight separatiqn of the two choruses, the
a dded clarity of inner detail in the eight-part
music, ma kes for much easier and . more enjoya ble Bach listening than in the inevitably
muddy and turgid single-channel rendition.
The chorus has a splendid sense of pitch
and of harmony, especially in the Bach, which
is one Qf the more difficult pieces in the choral
repertory. Not a chord is muffed, every harmonic progression is heard accurately a nd
snug without slipping and sl iding; diction is
excellent and the English words easily understood.
I'm not fond of mixed programs like this,
ranging the historical gamut, but that is what
most people do expect. This one begins with
old Alessandro Scarlatti, a juicy and pleasing
"E'-'Ultate Deo", . then moves to a post-Bach ,
pre-Mozart item by Graun and to the piece de
reSistance, the Bach motet; then, a sop to the
moderns, a piece about David and Absolom by
Norman Lockwood; I wasn't too much impressed. The end, nice and sweet, is "Beautiful
Saviour", decked out with humming a nd what
have you. A nice tape, all in all.
Mozart: Missa Brevis in F. Oberlin College
Choir, soloists, Robt. Fountain.
Livingston 713-BN
Stereo Rating: 3
This early-style Mozart Mass is sung with
the same choir plus orchestra-no doubt the
student orchestra at Oberlin Conservatoryand soloists, also student I would guess. It
seems more live in acoustics than the unaccompanied recording above, a nd is somew~at
more effective as stereo sound, compared Wlth
its monaural equivalent. An interesting facet:
the soloists are picked up au ttatu1'al, at stage
distance and at normal (d istant) concert volume. Alas, after so many years of amplification, we can't so quickly adjust to litera l concert hall practice! You'll probably feel as I
did that the soloists here, even with stereo's
aid' tend to be drowned in the larger sound.
Yet this is the way they actually do sound in
perfo rmance. Interesting because some stereo
producers have gone to the other extreme,
amplifying their soloists according to sta~dard
monaural usage. That doesn't work well either.
Stereo needs some sort of comprom ise on
soloists halfway between t he natural sound
and th~ accepted monaural balance, as used in
standard recording.
The Mozart is sung nicely and n eatly but
not with any great feeling; this type of music
is not at all easy to grasp for young people
today and t hough· the-execu·tion is impeccable
for the most part, I don't think this group
really is quite onto the style, except in the
Credo--wh ere a fam iliar Mozart motto
theme, the main theme of the "Jupiter" Symphony, is used to dramatic effect. But better
t his neat and accurate singing than the wobbly, sloppy renditions I've heard of such music
by older choirs.
Jazz Hystereo. Jack Millman Quintet.
Stereotape 'ST 5
Stereo Rating: 4
BROTHER, you won't find a ny discreet
mood mu sic on this l'oll! It's real potent jazzmaking, traditional in its form but definitely
more modern than Dixie and twice as
high powered. The recording is super-hi-fi and
effective 'a s a11 get out-monaural or stereo.
You'll li sten with a ll your ear s or none, just
like Bach. I liked it.
How different is jazz stereo techniqu e from
the stereo of the big concert hall classics!
This is a close-up, very loud studio job, quite
dead acoustically, and the end instruments are
right in the loudspeakers, in your r oom. But
the middle is right in the room too--this is an
intimate ensemble, if high-powered-and so
the stereo audible picture is natural and complete from side to side. Indeed, this is practically an Absolute recording, the instruments
seemingly right in your room without any
room-space of their own. Only the piano is
noticeably off in the background a few feet.
In this s!)rt of close-up work a surrounding
Jiveness isn't necessary, as it is in classical
concert hall recording where the middle of the
music is far out in front, at a distance. There,
AUDIO
•
AUGUST, 1957
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AUDIO
•
AUGUST, 1957
29
'-"11-'; .
,
PIM-10
you must keep your end instruments out of
the speaker boxes or you'll make hash of realism. In closeup popular music you don't worry
about a middle that's probably within a dozen
feet of the mikes anyway.
Classic chamber music will work out well
too in this style if it is the sort that flourishes
in dead, modern acoustics. But most of it that
we hear is unsuitable for dead studio soundit needs a soft Jiveness to go with its older
style. Take Bartok or Stravinsky, t hough, and
you can apply jazz stereo techniques to it with
stunning effect. It's modern.
'"
I suggest you look out for other Stereotape
jazz items of this sort, in case I don't get hold
of them. They're good.
Liszt: Piano Concerto # 1 ("Triangle").
Artur Rubinstein; RCA Victor Orch., Wallenstein.
RCA Victor. 8CS·31
Stereo Rating: 5
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hi-fi stereo is what yon're after. The performance, of course, is the best of the best, with a
superb orchestra and a conductor wbo knows
this music fo·r every bit of its wild hysteria
and icy cool control.
Somehow once again RCA has managed here
to get the sharp edge and exaggeration t bat
goes with hi-fi sound without introducing the
slightest trace of stereo spacial distortioninstruments that seem unnaturally close and
out of spacial context. The telephone-bell tria ngles and rolling snares of super-hi-fi are all
here, but in the stereo listening they seem to
be right down in the orchestra, on the stage,
as natural as you please. If this was made in .
Sympbony Hall, then an AB comparison with
the Messiab recording on Livingston (Unicorn) made in the selfsame place will be very
instructive. Such different effects!
Note incidentally that RCA is using thin
tape and very large center hubs, the recordings
appearing to the eye as skimpy-just the outside of tbe reel filled. But tbe timing is reasonably long when you play these rolls, whatever the looks of them. The recorded level is
somewhat lower. I'd say, than in that on otber
tapes made with standard thickness tape, but
the difference is not enough to make for noise
troubles. I have yet to hear any print-througb
in tbe RCA thin tapes, thougb I've heard a bit
now and then in some of the regular-thlckness
tapes from other companies. RCA h as it pretty
carefully calculated, I'd guess.
This is an unexpectedly interesting stereo,
one of the most successful solo-orchestra renditions I've yet heard-but in a way that
never would have occurred to me. It's recorded
chamber-mu sic style, close-to and dead , in
sharp contrast to other RCA classical tapes.
This, of all music! But it works.
First, the piano is picked up not with the
big, distant stage sound you might expect but,
instead, with a close and immediate sound
that suggests Mr. Rubinstein is either right in
your living room or, perhaps, on a small stage
Organ Concert. Austin Organ, First Meth.
In a tiny concert hall about fifteen feet from
Church, Evanston, III. Austin P. Lovelace.
you. Intima te, though the piano tone itself
Concertape 24-3
is enormous and beautifully natural. This
piano is definitely not in any conceivable large
Stereo Rating: 3
concert hall, as you hear it.
Now if that sound were combined with the
This is a conventionally competent organ
huge, spread-out orchestra in RCA's Boston
recital that somehow never gets far beyond
and Chicago Symphony stereos (and the NBC
a sort of neutral unimagination, though the
with Stokowski), there would be h - - to pay.
reasons are not too easy to fathom. The AusA big, close piano and an orchestra far out in
tin organ, somewhat modernized (I.e. converted to the old "Baroque" stops) has a serva big auditorium just don't mix. Your mind
would hear the pia no close-up " inside" the . iceable sound; of no great distinction. There's
orchestra's big space--which would put it in
a Sunday organ recital program, the u sual
the middle of the a ir like a Disney giant.
mixture of several Bachs , a bit of neo-RomanThere are such recordings. RCA's earlier
t ic loud organ and merging into modern. Nice
Brahms Violin Concerto with Heifetz come to
little item by Pachelbel (pre-Bach) and a
mind_ Heifetz and his fiddle, blown up to huge
somewhat colorless rendition of an old Daquin
size, seem to hover in the air somewhere above
(French) . Nothing very brilliant in the hi-fi
the orchestra . Disturbing.
way, neither hi nor low but plenty of well
Now maybe this new tape was an accident,
recorded organ sound. The playing is similar
maybe it was the calculation of a stereo gen-;-competent serviceable but not very exciting.
ius. Whichever was the case, the big, close-up
C .A,nd, to round out the neutral picture, the
piano is here matched to a close-up orchestra
stereo effect is good and an improvement over
in the same, rather dead chamber music style,
the equivalent monaural sound, somewhat
and the two coalesce with the greatest of ease.
broader , bigger and more immediate, but the
You'll have no trouble at all in placing the
total effect isn't anything very striking, even
piano right along with the orchestra (and the
so. Good liveness, but not really impressive.
solo triangle, not to mention an occasional solo
A good piece of neutral workmanship, from beviolin which seems to stand off to the left , . ginning to end. I was sort of bored.
right next to the piano). The whole music, 'V
I'd like to add, if you'll pardon my being a
piano and orchestra together, is close, lively,
bit on ,. the pessimistic side for the moment,
immediate.
that I !tID. not very enthusiastic about Concertape's round plastic boxes for tape. Numerous
Now I'll grant that this Concerto would
sound pretty silly in an actual chamber music
advantages a re claimed but I find them, with
hall. It wouldn't fit; this is a full-sized 01'their tiny feet, clumsy, uncomfortable, inconchestra. But the stereo effect of chamber invenient- particularly when they are stacked
timacy is another matter. It seems to suit the
in a mong their square counterparts. Can't r ead
music well and it makes possible the big piano
their labels easily, they tend to roll forward
sound and the big orchestra, brings the soloist
and dump themselves on the floor-also they
up close and the orchestra along with him.
are hard to open unless you pay close attenNaturally, the actual recording hall or
tion . . . well, this is a personal reaction a nd
s tudio was hardly of chamber music size. I'm
many tape users may dIsagree. So better look
speaking strictly of the imagined effect, as
at them yourself.
heard via this tape.
As for the musiC, Rubinstein plays in his
Organ Recital (Vols. 1, 2). Prof. Kurt
new and very musical manner for most of this
Rapf, Piaristenkirche Organ, Vienna.
work. The grand old piece rolls out with all its
Audiosphere 711-STi 712-ST
dramatic thunder, if with a good deal of
modern I;ligh tension as well. Only the last
Stereo Rating: 4
section shows that familiar hard pounding
Thi s recording from Vienna is mu ch bigger
that Rubinstein's powerful finger s produce
in sound than the above, more spectacu lar,
when he is just playing for show. Basically a
and
the stereo advantage is somewhat greater
good performance, if a bit streamlined, and
as well, not so m uch right- and left-wise as in
the orchestra plays up to the pianist througha more pronounced sense of presence and
out.
space. The registration, too, seems more flamboyant and showy, to match the big sound of .
Ravel: Rapsodie Espagnole; La Valse. the instrument and the large liveness. Both
Boston Symphony, Munch.
tapes open with familia r Bacb, the Toccata
RCA Victor CCS-36 and Fugu e in D Minor on one and the C Minor
Passacaglia on the other; Mendelssohn follows
Stereo Rating: 5
on both, and in Volume 1 there's room for a
Chorale by Cesar Franck, ending quite gloriRCA most assuredly has the rest of its clasously.
sical competitors by the scruff of the neck in
The actual differences all along the line-respect to stereo know-how for big band. This
from
the organ and the acoustics t o the peris another hi-fi stereo, deliberately worked out
former, the mike-set-up and the processingto sound that way and it's a huge success, if
AUDI0
•
AUGUST, 1957
aren't eas ily pinned down between t his and
the Concertape organ recital, but the over-all
effect is remarkably better here. Who was it
sa id genius is an infinite capacity for detail ?
The details here add up impressively, however
minor they may be in a ctuality.
I note a slight coming-and-go ing of highs
here, as though the tape were not a ligned secUl'ely in the driving. Also occasional slight
drop-outs. Could be my pl ay ing machine, but
better check you r copies.
The Music of the Bach Family, vol. 1.
Uoh. Bernard Bach : Suite in 0; Joh. Christoph Bach : Suite" Amadis des Gaules.")
Zimbler Sinfonietta, Burgin.
Boston (Livingston) BO 7-6BN
Stereo Rating: 3-4
(A lowi s h st ereo rating here merely means
that the mus ic, mos tly for string orchestra,
sounds fine with ordina ry recording. Stereo
adds a modest but not startling extra realism.
The several sections wi til solo inst ruments
~ome through with better stereo advantageh ence the double rat ing. The sound is lovely
- stereo or monaural.)
This is a most worthwhile series, sponsored
by Boston University, investigating the numerous members of the great Bach family with
t he Zimbler Si nfonietta, made up of Boston
Symphony men. Here we have first a perfectly
lovely suite by Christoph Bach, who was a
few years older than old Bach himself (;rohann
Sebastian)-a nd who writes mu sic much like
Bach's own Suite in D , tempered with a bit of
Handel's sweetness. A rea lly first-rate work
a nd a joy to listen to, if somewhat on the
feminine s ide compared to ;r. S. himself.
Somebody h as bollixed up his Bachs on the
second item here recorded. Notes say that t his
Christoph was born some forty years before
our Bach a nd died in 1703-the big Bach died
in 1750. Well, the music on the tape is a lovely
su ite t hat I'd say dates from after Bach, at
the earliest the middle 1700s a nd more lil,ely,
by the sound, from the French Revolu tionary
period, or in Mozart's time. A mere cent ury
out of step
Whoever this Bach is- I don't h ave a dict ionary ha ndy to begin a search- h e wrote
yery melodious, Mozarty music, somewhat like
Glu ck's, with a mixture of Gretry, t he bumptuous revolu tionary composer of France. Most
li steners won't wo r ry too much about which
Bach is whi ch among these less known t ribesmen , and this mu sic, Bach or no, will sell i tself n icely.
Music of the Bach Family, Vol. iL (K.P.E.
Bach : Symphony in E Minor; W. F. Bach:
Lamentabile and Presto, Sonata for Two
Flutes; W. F. E. Bach; Sextet in E Flat.) Soloists, Zimbler Sinfonietta, Burgin.
Boston (Livingston) BO 7-7BN
Stereo Rating: 3-4
This volume features two of Bach 's sons
and a later Bach, about the last, wh o didn't
die until 1845. Karl Philipp E ma nuel Bach
was the most .gifted and influential of Bach's
sons, of a deeply serious and introspective
nature yet a man who became t he leader of
t he world of music in the mid-1700s, famou s
throughout E u rope. His very expr ess ive mu sic
is' now coming back into fash ion. This symphony is Gluck-like except fo r its serious, personal cba racter. A fine sample of t his cultured
and sensitive great musician at his best.
Wilhelm Friedemann Bacb, the old man's
{)Idest son, was relatively a shiftless soul
though plenty gifted when h e got around to
. ~omposing. His duet for two flutes sounds
more like papa Bach t han any of t he younger
sons' music; it is played h ere in such huge
milted liveness t hat you 'll think there are
dozens of flutes play ing. Only two, and stereo
h as t hem jus t Slightly separated to right and
left, ol'f in t he huge a uditor iu m space.
Finally, there's the little known Wilhelm
F riedemann Bach who lived on into the midNineteenth century. H is sextet will rem ind
you of the Beethoven Quintet Op. 20, w ith
nice, Simple, bouncy t unes and plenty of closeup woodwind a nd horn color. Rather sappy
stuff but well written a nd entertaining in
sou nd .
•
AUDIO
•
AUGUST, 1957
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T
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·
HAROLD LAWRENCP
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~~
<""' .._ . . . . . .
PiPer's~~:
om, Tom the
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Stole a pig and away he run.
He ran to a town near Baltimore
and sold the pig to a}JUtcher store.
The pig changed hands
- and soon he possessed
A twin-coned N orelco - F.R.S.
His father was piping
when T om retu rned home
T om slipped inside-unseen and alone
The piping was tinny the music was weak
Tom quickly changed speakers and thus did he speak:
" N ow play the pipes father
and notice the tone
Such fullness and quality
You have not known.
T he reason - Norelco!
T he speaker - T win- Coned!
Both high notes and low notes
Are now fully grown ."
T he father - enchanted continued to play
The Full Response Speaker
soon held .full sway
The neighbors - attracted as gnats to a light
Gathered in groups and sighed
with delight
The pig was fo rgotten the theft was obscured
By the beau tiful music that soared,
.<;:lung and cured.
There is a moral to this tale
1
1.iii::..
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Which we are pleased to give ~t~
To own and love Norelco
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It Pays to Applaud
..... '"'
Hi cksville, L. L, N. Y.
w.ho _can _afford . tic .. Tr.ained.claques performed man}' subtle
it ;eldom works alone. An accomplice,
and varied tasks under the expert direction
pretending to be a customer, listens to
of a chef de claque, or claquemaster. Priol'
his sales pitch in seemingly r apt attention.
to opening night, chefs de claque attended
When a sufficient numuer of passersby h as
rehearsals and made copious notes. If it
gathered a round, he digs into his pocket.
was an important and lucrative production,
makes his purchase, and leaves. But he'll
an elaborate network of claques was pu t
return in a few minutes for a repeat pe rinto operation. Inside the theatre, one
formance, unless the .policeman on the beat · -gl' l'rup was assigned the job of clapping.
is unfriendly and the peddler has to fol d
stamping feet, calling for encor es, and cryup his stand and silently steal awn )'. In
ing "bravos. " Another squad was deployed
the langua ge of the trade, the phO"J buyer
throughout the audien ce with instruction s
is known as a "shilL" His job is to stimuto la ugh or weep at appropriate moments,
late bona fide .purchases, working on the
One member of t he team was usually made
time-honored principle that an unnttendec1
to hiss from time to time, provoking viosta~l d , like an empty shop, is bad for busilent shushing and arousing the audience's
ness.
sympathy for the playwright or the comIn the world of music and drama, the p oser. Th e elite of the claqne, the wellshill's counterpart is found in th e dressed ' spectator,' was placed in the
"claque."
Derived from the French , bo),es or other e:l>.1)ensive seats where he
c laq~te1' (to clap), ,the claque's fun ction is
could whisper flatte ring remarks about· the
to prime the pump of audience acclaim, performance, meant to be overheard by his
even when the weil is dry. One of the fir st
affiue~t n eighbors.
hi storical examples of the nse of the
During liftermission, claques 'transferred
claq ue dates ba~k to the Rom an Empire
to the lobbies to disseminate superlatives.
when Nero hired 5000 soldiers to cheer
Outside the -theab'e, they would sta nd in
his own performance as an actor-hence front of th e box office or placards a nd exthe early name for claques: "Romans."
cha nge such comments as "What a mag During the past three centmies, claques . nificent performance!" or "Did you evel'
have ranged in quality from the crude (if
hear th at role sung better in yom life'"
less extr avaga nt than those of the Em - Naturally t hese ' observations wer e mnde for
peror-fiddler) to the more sOl,)histicater1
t he benefit of innocent strangers. When II
varieties. A sixteenth-century French 'poet
lai·ge purse was involved, claques fanned
bought up quantities of tickets in advance
ont in to the city, spl:eading the' word' in
for all productions of his play and handerl --' cafes, bars and restaurants.
them out to in terested friends. Operatic
Claquers' professional fees were careperformances in eighteenth-century 'ltal:v
fully itemized, even for mere applause, as
were generally noisy affair s. At the conthe following list of services of a n Italian
clusion of an aria in a Milan productioll . ·fiTlll in 1919 indicates:
in 17 29, the claque (divided between the
For appla nse on entrance, if a
pit an d the gallery) set up a din of sho ut25 liregentleman
ing a nd applause. Then the pit co rp s beFor applause on entrance, if a
gan to strike th eir benches with sticks .
15 lire
while their gallery cohorts "sliowered the"
lady
p m'quet audience with thousands of printed
Ordinary applause du r'ing perleaflets cont aining sonnets in praise of the
10 lire
f orma nce, each
singer. It was not until the nin eteenth cen Insistent a ppla use during pertury that the m·t 'of claquery r e3ched its
formance, each
15 lire
zenith.
17 lire
Still more insistent applause
The father of -the modern claqne was n
For interruptions with" B ene! "
French theatrical entrepreneur named S a u ·
5 lireor "Bravo!"
ton. Having put considerable amounts of
50 lire
For a "Bis" at any cost .. .
money -i nto operatic-and t hea.t.rical enter ·
Wild enthusiasm-A special sum
prises, he was determined to protect hi s
to be arranged
investments. Since 'opening nigh-t-.a-ppla use
was a n essential p art of success, he--'emFl'olI\ .. the outset, people sneered at the
.
very mention of th e word, claque. Yet
p 1oye d claflU!lS to !,rOVlde
the necessary
claques ha ve ser ved useful purposes. A
stimulns. It then occurre~l t.o _Sail ton that
. orgmuze
. - bawls- of claqu es a11(1
cJl0ractel'
in Guy - En'd ore's biographical
he mIght
co
rent out the.i.r.. services. This r esulted in' hi s-" ~1Ovel about Alexandre Dumas, "King of
tory's first claque concern w h 1se slogan
PaLis". (Simon & S chust er), speaking in
was: "Dramatic success' gU1u·anteed." The '.. (l-e1'eIH,e of the claqu~, says: "Imagine some
evening, when it is r aining -and' Cold wind
critics unofficially dubbed Sauton's firm :
"Claques ' College."
is blowing, t hat you come into the theatre.
Although intended. as a slur, th e designa- Imagine · that you -sit here wondering·
tion "college '.' was not altogether .fa-ntaswhether your feet a r e wet, whether you
will ' be sneezing tomorrow, whether you
.. 26 W . Ninth St., New Yo-r7c. 11, ·N. Y.' wo uldn 't have done better to have stayed
'T HE SIDEWALK PEDDLER
a
,AUDJO
32
....- ot;
•
AUGU'S,T, 1957
hom e ... t he actors a nd actresses do their
best, but it is a cold, damp house, a nd the
cast cannot put its heart into its work, and
the play fails not because it isn't a good
play but simply because in wet tinder the
best flint and steel ca n only fizzle out.
No w · do yo u see where · the claq ue fits in ~
Do yo u see knv they warm things up, st a rt
the ha ll rolling anO create at fir st a u artincial enthusiasm b ut which soon becom es
the rea I thing as the audience quickly loses
itself iu t he play, fo rgets the weather outside, and has a good time ~ "
Likewise, the absence or presence of a
skilled opera claq ne at tim es meant t he
diffe!'ence between success a nd failure .
'Wh en Caruso nrst snng in Gluck '8 seldom
hea rd opera, Annide, at the Metropolitan
Opera House, hi s big arias were greeted
with stony silence. In desperation, he appealed to Ga tti-Casazza who in .turn asked
tenor Alessandro Bonci for ad·\-iee. Bonci
said that his own ,alet knew e"ery note
of th e opera. Thu s, with Bonci's man Friday on hand, the audience applauded fr equently and in the right places.
Wh ~n th e claque's ' job is to stim ulate
applause for t he opera as a whole, the eff ects of their work can be beneficial. I>ersonal cla.ques however are something else
again. In the f all of 1955, a New York
chef de claque was sent to San Francisco
to stimulate an ovation fo r Reuata T ebaldi
in""a: performance of To sca. The demonst ration led to a precedent-shatte ring encore of
"¥issi d ' Ar.te' '---wh·i ch--hoth ·the ·cl'itics ..and
public found repugn ant.
The Tebaldi-Callas feud has re's ulted ill
supporters of one singer a ttending the
other's performance in order to hiss an;
unsteady high note or muffed phrase. So
far, neither star has dared to go as far as
a certain Mme. Tofts in 1704. This English singer was said to have sent her servant to the theatre where her chief rival
was appearing in order to pelt her with
rotten oranges.
According to John Bennett, an Italian
'from the BrOIL'i: who became a professionn I
claquer under Bonci, and is now unofficial
chef de claque at the Metropolitan Opera
House, a good claquer never draws attent ion to himself; he merely "cues" applause.
•
COMING HI·FI SHOWS
Insritute of High Fidelity Manufactu re:s:
Sept. 17-21-Chicago : Mo rrison Hotel
Oct. 7-12-New York: N. Y. Trade Show
Bldg.
Rigo Ente rprises:
Sept. 6-8-Cincinnati: Sheraton-Gibson
Hotel
Oct_ 18-20-Miami: McAllister Hotel
Nov. 1-3: Portland, Ore.: Multnomah
Hotel
Nov. 8-10-Seattle: New 'Washington
Hotel
Nov. 22-24-St. Louis : Statler Hotel
Independent:
Sept. 12-15-Portland, Ore. : New H eathman Hotel
Oct. 25-27-Mexico City
Oct. 31-Nov. 3---'-Habana, Cuba: Copocabana Hotel
Nov. 8-10-San Ju an, Puerto Hieo: Normandie Hotel
AUDIO
•
AUGUST, 1957
What makes this
tuner outstanding?
One of the nation's leading electronic testing laboratories has reported that, to their
knowledge, the new Altec 306A is the most sensitive tuner ever manufactured. At the
Chicago High Fidelity Show, one of these tuners equipped with only 23" of 300
ohm antenna lead provided perfect reception on twenty-fuur FM stations, including
one in Grand Rapids, Michigan. This is a performance which we believe approaches
the theoretical limit of sensitivity that can be obtained at the present stage of electronic science.
But why is it so good? Its basic circuitry is quite conventiona l, using the latest
Foster-Seeley (Armstrong) detector circuit. The difference lies in the application
of these bas ic circuits; in the caref ul selection of the finest components regardless of
cost; in the hundreds of hours spent designing a chassis with the shortest possible
wiring distances between components; in the development and application of circuits
_to achieve their full performance capabilities.
Among these exIra points of superiority are a fully shielded six gang tuning condenser, complete isolation between the transformer and power mains, and a dry
rectifier of very long life and stability. Besides the Foster-Seeley detector, the FM
section fe atures a "cascode" low noise RF stage, a triode low noise mixer stage,
AFC and Iwo limiter stages. The AM section has three IF transformers with optimized coupling for flat pass band a nd max imum noise rejection and a special high
Q ferrite rod antenna. N at ura lly, the 306A far exceeds FCC radiation requirements
and is approved by Underwriters Laboratories for safety in the home.
The specifications given below reflect fully the quality inherent in the Altec 306A.
Compare them with any other tuner specifications, the superiority of this latest .AItec
product will be obvious. See it at your nearest Altec dealer's showroom. Its quality
is fully evident in its beautiful appearance a nd craftsmanship.
NOTE: Sensitivity figures are given for the standard 300 ohm antenna, and can
not be compared with figures derived from special 75 ohm antennas. To convert
75 ohm antenna sensitivity to standard 300 ohm sensitivity, double the published
figure. For example: a 2.5 microvolt sensitivity on 75 ohm antenna is a 5.0 microvolt sensitivity on 300 ohm antenna _
Frequency Modulation- a ntenn a: Standard 300 ohm. m ax imum sensitivity: 1.1 microvolts
• quieting sensitivity: 2.5 microvolts for 20 db ', 4.0 microvolts for 30 db ' • selectivity : 6 db
ba nd width 185 kc, 20 db ba nd width 300 kc • frequency range: 87-109 MC • image rejection :
48 db • IF rejectio n : 72 db • freque ncy response: ±0. 5 db, 20-20,000 cps. distortion: Less
than 1% at 100% modul ation, Less than 0.4 % a t 1 volt output
• standard 300 ohm antellna
Amplitude Modulation - a ntenna: Built-in Ferrite Rod " Loopstick" plus external antenna
connections . max imum sensitivity: 3 microvolts. loop sensiti vi ty : 50 microvolts per meter.
selecti vity: 6 db ba nd width 11.0 kc, 40 db band width 27 kc • frequency ra nge: 534 kc1675 kc • image rejection : 66.5 db • IF rejec tion : 58 .5 db • distortion: Less than 1.5 % at
30% mod ulatio n. output : 1 volt cathode follower m a tched for 440 a nd 339 • power supply:
117 volts; 60 cycles ; 65 wa tts . tu bes: 2-6BQ7A, 1 each 6AB4, 6 BA6, 6AU6, 6AL5, 6BE6,
12AU7 • controls: Tuning; on-off, AM, FM-AFC
Price : less cabinet S183.00: blond or mahogany cabinet s15.00
ALTEC
FIDEL I TV
ALlEE
~
IS
HIGHEST
FIDELITV
Dept. 3A
1515 S. Manchester Ave., Anaheim, Calif.
161 Sixth Avenue, New York 13, New York
33
AUD_AX
TOKE AR·M
NOW IN KIT FORM
Anyone can assemble it in about 10 minutes-and save 50%! "Selector-Index"
permits instant adjustment for any
stylus pressure. Newly-designed cartridge housing, permits all-important stylus-to-groove alignment at a glance. Accommodates ANY make cartridge.
ere.
KT-12 $14_55 NET
factory-auembled
Edward Tatnall Canby
$24_00 NET
"Duplicates famcms Auda"
transcription arm, long ret'ognized as tops _••"
(Popular Electronics)
---~
LISTENING QUALITY
IS EVERYTHING!
ImpMtial Lab reports on the nnu Arid."
Hi-Q7 mtllfnetk eMtridge:
A. leading recording studio:
"Because readings sl;1owed
an amazing total lack
of distortion, checktests were repeated
3 times"
Consumer sheet:
"Good frequency
and transient relponse. Practically
no high frequency
distortion.
intermodulation
distortion."
Listening quality is everything and
Audax Hi-Q7 has it to a degree not
equalled by any other pickup. But HEAR it yourself • •' . there ;s no other
w.yl Net $47.70, with 1 Chromatic Diamond and a Sapphire . • . Other model. as
low as $20.70 Net.
Low
~;f1 )
----
,
~~
I
STYLUS-BALANCE
"Th;s really works • ••" (Audio Magazine)
Stop deformation of record grooves I Only
Audax Stylus-Balance can give you the allimportant cet'tainty of correct stylus preslure-ALWAYS. Precision-calibrated like
a pharmacist's balance. Works w.ith any
arm and cartridge. Gold Finish_ Net $4.80
LISTENING QUALITY CUTTERS
Flat to 14,000 cps. Distortion 0.6% at 1000
cps. Fully modulates groove with input of
about 16 db with 220 lines. Z's up to 500
ohms. Two models:
H- 5 .
. Net $111.00
. Net $75.00
H- 4 .
----
Any item, w.hen shipped from N. Y. add 40¢
,,---------------------------------------:
AU OAK
:
500 - 5th An., New York 36, N.
:
0
o
'1'-
Att: IIr. A.
I enclose 25¢ for handling & postage. Pleas.
.end FREE $1.00, 22-page "ELECTRONIC
PHONO FACTS" by plonoor Maximilian wen.
Sond FREE latsst catalog & name of neonst
duler.
Naml
Address
:
COMPANY
•••••.. _ ••••..•• _ ••.••.. _ ••.••• _ ••
•••••••• _•••••• • •• ••• • _._ ••• • • _••
City. • • • • • • • • • • •• Zone
.0...
Stat. . ...... .
!---------------------------------------~
34
1. STAGGERING
Well, the cards seem to be increasingly
stacked against the staggered-head stereo
system, admittedly the easiest to work with
when it comes to low-priced stereo home
equip;ment production. As already mentioned hereabouts, the stacked head is this
department's choice for all stereo, and I'm
hoping that pretty so.on the necessity to
make two types of stereo tape will have
gone by the boards-all machines will play
stacked-head. In addition to the new RCA
Victrola, described here last month, there
is already another inexpensive stereo system out with the desirable stacked heads,
from Bell.
It would seem to me that the usual laws
of manufacturing economics will operate
here. Stacked heads have been trickier and
more expensive, to date, but as the knowhow in their manufacture increases and as
their use spreads, the cost will drop and
drop. It won't be long before a stacked
head stereo player is no more expensive to
put together than a staggered head set-up
-maybe it's so already.
However, the laws of model-changeover
also operate and so there will be a time
delay until present staggered-head equipment drops out of production in the normal course of events. Decisions already
t aken today may be a year or more in
reaching down to the public level. So staggered stereo is bound to stagger on for
awhile, under any circumstance.
But as I say . _ . the cards are stacked
against the offset heads and they are
clearly in line for eventual retirement,
though the changeover will be staggered
to offset any hasty obsolescence, in line
with public interest. Stacked up -'against
staggered, the in-line system is bound to
win in the end, even if the victory is something less than staggering.
2. Earphone Binaural
Incidentally, my once-ardent interest in
what could be called "true binaural' , that is, two-channel recording reproduced
via earphones-was given a new lift by a
recent Bogen ad (See AUDIO for June, inside front cover) depicting a gentleman in
Japanese stance-sitting with his legs
crossed in horrible discomfort--listening
via earphones to what purport to be two
channels, one for each ear. (Anyhow, there
are two wires soaring off in opposite directions.) The ad is for a 2-channel amplifier
which, of course, could be used either for
standard stereo; with loudspeakers, or for
two-channel earphone playback as illustrated, though stereo was obviously intended. Just an ad-man's quirk.
Yes, earphone binaural remains rather
dismally impractical in any commercial
sense but, as those who have experimented
will know, it can produce sound effects so
utterly startling and different that stereo
can't hold a candle to it, by 95 percent.
True, the directionality, though very definite, is apt to be addled with earphones
(music sounds as though it were overhead
or behind you sometimes) but all other
effects are incredibly realistic. Only witli
earphones can you re-create the actual twoeared acoustical conditions of true listening; speakers can never do it. With binaural eal'phones on your head your ears are
in one place and the rest of you in another-quite literally_ You hear somebody
talking to you a few feet away and you
whirl around-to find nobody there. You
repeatedly fail to distinguish between the
actual, happening sounds and those recorded-especially when the recording has
just been made on the spot_ An eerie, uncanny effect!
But don 't think that any stereo tape
will do for earphone listening. Results will
vary, literally, as widely as the spacing of
the mikes. For proper ' , true binaural"
listening with phones your mikes must be
reasonably close to ear-distance apart
though a slight exaggeration, say two, or
three feet, adds extra punch and, so to
speak, touches up the sound highlights.
Beyond a bout three feet, mike to mike
(ear to ear) the two sounds begin to lose
fusion, just as a too-widely spaced stereo
picture slips out of register and becomes
two pictures-you see double. With a
wider spacing of mikes, the two ears begin simply to hear two different t akes of
the same sound from separate locations;
the effect, to put it another way, is like a
composite photograph where the foreground is the same but the background detail differs and does not coincide. This
you can actually hear, this effect of two
recordings heard as separate entities by
each ear. Not good and not binaural.
Since most stereo recordings are made
with mikes widely spaced apart -anywhere
from 20 to 60 feet-the earphone fusion
into one natural two-eared sound is not
likely to take place. The ears can accommodate only a slight difference between the
recordings, a difference that can be t aken
as ear-difference. Three feet is about the
limit of tolerance.
Never forget that earphone two-channel
listening reproduces the original liveness,
as of listening on the spot, absolutely
literally (except for some confusion in di'rection) , and tha t therefore earphone binaural recordings can be made, and should
be made, at the spot where the sound is
normally heard. No close-up mike techniques, and you can make a recording of a
concert hundreds of feet from the stage
and still it will sound exactly as good as
it does "in the flesh." Similarly, speech
recordings c<J,n be made at normal listening distance, in any old acoustics, with re-
AUDIO
•
AUGUST, 1957
sults precisely the same as the actual listening at the same PQint_ This, when yQU
begin to. think abQut it, is a f a bulQus difference.
In fact, if yQU are talking a bQut l'iteral
sound reproduction, this is the only known
way in which it may be achieved. It dispenses in one fell swoop with the entire
business of mike technique, r emQves all
liveness trQubles (Qther than na tural Qnes,
as heard by two. ears), makes intelligible
recQrded cQnversatiQns PQssible in crQwds,
at distance, in nQisy places like restaurants
and baseball games .. . Well, try it YQurself and see. A fascinating hQbby, and if
yQU can affQrd to. hQQk up five 0.1' sbe earphQne sets, yQU can h ave an audience fQr
yQur fun.
3. Sight Unseen
Quite Qften an item CQmes to. my nQtice
that hits me instantly as a gQQd idea, an
impQrtant Qne-even sight unseen and
bugs untested. Such items remind me Qf
QUI' familiar legal principle that perSQns
are innQcent until prQved guilty. In these
cases Qf which I speak the principle involved is,.. Qn the surface at least, so. gQQd
that the idea is just plain autQmatically
excellent until prQved ba d, 0.1' unwQrkable,
0.1' full Qf bugs.
Fairchild's newly annQunced ElectrQnic
Drive turntable is Qne such. I haven't seen
it and I ·have no. idea, at this writing, what
sort Qf IQng-range perfQrmance this t able
may turn Qut, nQr what bugs-if anyhave yet develQped, what disadvantages
the table may have in cQmpariSQn with
Qthers. But the idea Qf it is just superb,
Qne Qf thQse things that make yQU say,
"Why didn't SQmeQne think Qf that befQre~ "
What's so. gQQd f ElectrQnic Drive. The
F airchild gets its speeds by using a hysteresis mQtQr, which resPQnds accurately
to. the frequency of an alternating current
but is mQstly unaffected by changes in
vQltage. Ordina rily these mQtQrs are used
to. keep the speed unifQrm and exact ac o
cQrding to. the cQntrQlled frequency Qf Qur
hQuse current. In this new design an electrQnic PQwer SQurce gener at es its Qwn
separate PQwer, using the hQuse current as
the primary PQwer, and this newly creat ed
current is adjusta ble in frequencythereby running the mQtQr at varying
speeds. Brilliant idea !
Bugs ' I'll bet there are SQme, and I
wQnder hQW stable the frequency is, Qver
IQng periQds. But I 'll al so. b et that t he
ma jQr bugs in the idea have already been
squashed pretty fiat, Qr else the unit WQuid
nQt have been launched.
The r eally brilliant u sefulness Qf such
a t able is that it i s independent Qf bQth
vQltage and fr equen cy variatiQns in the
line cunent. It not Qnly can maintain its
Qwn speeds, at least in theQry, r egardless
Qf changes in the SQurce current Qver a
cQnsiderable r ange, but-perhaps trickiest
Qf all-it will run Qn any Qld cycle r ating,
mQre Qr less. That is, this unit will give
the same speed from a 50-ops house outlet
as from a 60-ops Qne. It will run a steady
speed when frequency changes, as well as
when vQltage changes.
I can just see the eyes Qf thQse who. h ave
tried to. play r ecQrds in f Qreign cQuntries
beginning to. PQP! WHAT f Y QU mean a
t able that dQesn 't car e what happens to.
the line in the way Qf variatiQns, that will
play Qn 50 cps as easily as 60 withQut that
dismal change in pitch ( a minQr third)
that catches the unwary so. Qften 'i Yep,
that's it.
YQU see why I f all fQr this idea, sight
unseen. FQr many peQple, who. h ave suf-
AUDIO
•
AUGUST, 1957
A Professional Unit
Of Unlimited Flexibility
and Matchless Performancel
THE FISHER
Master Audio Co·n trol
Model
ao-c
HE SINGLE, most popular, self-powered pre-amplifier with
controls in high fidelity history ! THE FISHER Model 80-C
MASTER AUDIO CONTROL is of a quality normally encountered in
broadcast station console equipment. Designed for simplicity in
operation, the 80-C represents the high fidelity enthusiast's ultimate ideal. No other unit offers all of the features found in THE
FISHER 80-C - uniform response within 0.25 db from 20 to
20,000 cycles; 1M distortion and hum virtually non-measurable;
accurately calibrated 4-position Loudness Balance Control;
Balanced-Spectrum Bass and Treble Tone Controls; separate
equalization and preamplification directly from tape playback
head; complete, 5-position mixing and fading facilities on two
to five channels; sixteen combinations of phonograph equalization with exclusive lever selector; push-button Channel Selectors,
which, in addition to connecting the desired audio input channels,
simultaneously operate the AC power to auxiliary equipment;
individual channel indicator pilot lights. DC on all filaments; two
cathode follower outputs. TUBE COMPLEMENT: 3-12AX7,
1-12AU7A. SIZE: 12%" wide x 7 1/2" deep x 4 1/2" high.
50
Chassis,
T
$99
Price, Slightly Hi gher In the F nr West
Mahogany or Blonde Cabil1et, $9.95
WRITE TODAY FOR COMPLETE SPECIFICATIONS
FISHER RADIO CORP •• 21-2944th DRIVE • L. I. CITY 1, N. Y.
35
fered no end from variations in current,
the , !Jugs will have to be formid~ble before they, wil~ pass up such au Item as
this. '", ,¥ "i "
''" .
'.
Two' nlodels, a oue-speed version opera~ei! ,directly from the line, ,but in which
the Electronic Drive can be installed later
if 4esj!",~ d-:-~~d ~he _ fo!lr-speed model(~hat
silly 16 0/3' rpm again), ,which, as you'll
now understand, is driven dir~ctly. from i
the motor without any of the usual g~ar­
shift arrange)llents, since the !11otor , itself
changes spef:)d. ' Really something-:-again
as I say, in theory; '~nce I ha'\T~n 'L tJ;.~ed,
it. I advise all .tJ~ Qse,:,who have:, p,roblems
of fluctuating pjteIi., to in;l'es~igate' immediately. Oh yes/ ''the tablev·also ' Cll;n be
varied or "tuned" at each ,. of· •thE) fOUl;,
speeds, for exact pitching, "as !iu a few
other tables-Garrard and :'l.Qonnoisseur,
for instance. An a~,ded: ~,t~itt ,
" f' .
*
SR-2'OO DElUXE 25 WAH CONTROL
AMPLI FIER with exclusive SR features :
VARIABLE RUMBLE FILTER fo r "picking ," out low frequency interferences.
VARIABLE_SCRATCH FI LTER eliminates
high frequency interferences at exact
poi n't source.
9 POSITION SLIDE RULE DIAl. Another
SR first . Functional and beautiful, it
do~s away. with the normal visual com ~ plex ities.
OUTSTANDING FEATURES : Bass and
treble boost and attenuation 15 db at
40 and 15 KC with only 1 db variation
a t mid-frequencies. Feedback around
, every ' tube. 1 .5"/0 1M and .3'''/0 harmonic d istortion a t 18 watts. 6 position
equalization with feedback compensation for both upper and lower frequen: '
cies. Phono - AES, lP, FFRR, fU R,
RIAA, 6th position for tape deck input.
Va ri able contour (loudness) control.
Fo r' new illustrated brochure, write to
'Sar'g~nt-Rayinent Co., 4926 E. 1 2th St.,
Oakland 1, Californ ia.
36
*
*
The other sight-unseen item is simpler
but even more fundamental- Audio De-,
vices' new low-print-through tape.
We live in such a short-term world iu
recording! The old 78 disc masters have
managed to last a half ceutury already in
some cases; but the vast library of re:
corded tape built up during the last short
decade has been horribly threatened abov~
all else by that ominous magnetic phenomi
en on known as print-through, where the
recorded signal gradually prints itself
from one layer of tape onto the next to
produce a slowly increasing "echo" that
eventually makes hash of the recorded
sound. Tape itself might :seem flimsy
enough, from the historical point of view
- and we do hope that our descendants
a few hundred years from uow will have
some records of our many activities still
in existence-but, if I am right, the physical flimsiness of plastic is as nothing compared to the threat of print-through.
In the face of this menace, many recording companies and broadcasters have
instituted vast programs of regular copying, renewing their entire tape library
every four years or so. An incredible operation, and a despairing one as well, for
over the centuries the copies will inevitably
become less and less good in quality of
sound and in no time at all, relatively, the
sound will have deteriorated to the point
where the print-through is no longer worth
f ussing about! Any way you look at it, the
future for taped material has looked
pretty grim up until now.
I quote only one sentence from Audio
Devices' announcement. "F"om meaS1trements made over a pe1'iod of years, it
p1'esentZy appears that stored "Master
.thtdiotape" (the new brand) wi.!! take
11t01'e than 100 years to reach the printtll1'ough level that now mm'S standard tape
in one week."
Now if that is true, if it is borne out
by longer t ests (up to 100 years, let's
say), then this is truly a revolntion in
tape, though the resnlts will be virtually
nil-for a few weeks. I suspect that there
will be a wholesale converswn tQ this tape
in the professional world in spite of a
higher price and that even the home tape
user will find the new material a good
idea for his own concept of r ecorded permanence. Maybe it will soon become a new
standard for the industry. I hope so-if
all of these claims are substantiated. It's
a great relief to know that maybe posterity will hear our tapes after all. That
is, if they feel like it.
4. The Fi in Toyko
My long-time correspondent in Tokyo,
now Bureau Chief of the Associated Press
there wrote me the usual newsy letter
back' at the turn of the yea'r which, as
nsual, I haven 't got to answ:ering yet.
You'11 remember when, awhile 'back, I
passed on his tips about Japanese hi-fi
equipment, a short time before it began
to appear in our own ads in this country.
He had then been making RJ cabinetsde-luxe for his Tokyo friends and I suggested, rather mildly, that perhaps a ,word
or two with the ' designers of that small
cabinet would have been a polite gestUl'e
towards chivalry, even if a royalty arrangement would be impractical for his
very small output, strictly not as a business.
Well, he took me at my word, consulted
with Bill Joseph (" J" ) and made up a
pair of the superest super-RJs you ever
saw, hand-designed and individually constructed by Japanese craftsmen. These he
shipped over to Joseph as a gift, and
everybody i s very, very happy.
, I 've seen , the gadgets and heard them
briefly in a stereo set-up-excellent_ They
are made of 12-ply Philippine Mahogany
with a genuine black lacquer surface, 114inch co,ner bracing inside for 'Solidity.
The speakers are hand-picked for low resonance, the J a panese model sold in the
U.S. as the "Panasonic" (so he tells me),
' the Matsushita Denki "N ational" 8PW-1, and they 'Sound not unlike the
Wharfedale Super 8jCSjAL. A set of
cables with mike-type polorized connectors· was included in this fabulous gift, arranged so that the speakers can be
switched in an instant from stereo set-up
to single track two-speaker. (That is, assuming you don't have a tape player that
makes this circuit shift internally_) Joseph
carts them around in his Buick, for all to
see and hear.
This Tokyo American, by the way, has
assembled something like 35 hi-fi systems
to date for friends and associates over
there, a ll in his scant spare time, as a
hobby that takes his mind off the eternal
news and its eternal tension. A hi-fi fan
if there ever was one_ His own speaker
systems weigh 200 pounds apiece, also in
12-ply mahogany and lacquer, a "beefed
up" Klipsch design (with permission from
Klipsch himself ) , and the components inside are all Wharfedale. He says he's
broken many a hi-fi heart with the outfit. Hi-fi is booming along in Japan, it
seems, and if they have merely reached
what he terms "first-class second class"
levels of excellence in their equipment at
the moment, they are getting the hang of
the business and should be topping the
best anywhere before long_
Music ~ The man doesn't say a word
about that, like a good hi-fi man. What I
wonder is, what do the Japanese play on
their hi-fi systems ' If it's the standard
line of American-European music-pops,
classical, folk and plain zany- then the
Japanese must r eally be well on the way
to cultural Westernization! I have no
doubt that jazz has, penetrated there as
powerfully as it has in most of the world;
it is our greatest cultural ambassador
right now, whether you like it or not. Bnt
Beethoven and Haydn and Brahms, out
of Europe, and maybe "My F air Lady"
from hereabouts-plus a hunk of Musique
Concr ete from France . . . . wonder what
a Japanese hi-fi library would sound like '
I'll probably find out in the next letter
from Tokyo.
•
AUDIO
•
A{JGUST, 1957
AUDIOCLINIC
(fl'om page 2)
of the circuit. Since the zero level indication of a standard VU meter (which is
actually only an a.c. voltmeter) is 1.228
volts, this indication would represent .096
watts in a 16-ohm circuit, 0.19 watts in 8
ohms, or 0.38 watts in 4 ohms. Any power
output above this could be read at the zero
level indication on the meter by adj usting
the potentiometer. In practical use, the
potentiometer would be set at zero and the
level adjusted on a typical record so as to
satisfy the requirements of the hall. Then
the potentiometer would be turned up to
obtain proper VU meter swings, and left
at this setting. By adjusting the volume of
all other records to obtain the same meter
swings, one could be sure that the sound
output was the same. While this method of
connection is not the professional way, it is
relatively simple and will give satisfactory
results.
Echo Effects
~.
Q. I have a tape recm'dm', and I am
wonderi.ng how I can create the echo effects
which al'e so common. I know that tape
1'ecorders are used for this PU1·pose. E. Wil-.
Iiams, Brooklyn, N. Y.
A. Unless your tape machine is one having separate record and playback heads,
you will be unable to create this effect
without adding another head, which might
be difficult if your motorboard is as crowded
as many a re today. It would be especially
difficult because of the requirement that
this additional head should be placed as
close as possible to the record head. Regardless of whether you added a playback
head with its accompanying preamplifier or
whether all this equipment was already
contained within the unit, the procedure is
the same. It would require a two-channel
mixer whose output is connected to the input of the recording amplifier. One channel
is connected to the signal source. Adjust
the level of this channel, which we shall
call channel 1, for proper level indication
in the conventional manner. Next, connect
a pair of headphones in the monitor position and set its selectsr switch to the playback position. Next, connect channel 2 to
the output of the playback preamplifier.
Leave the gain of channel 2 at zero and
start to record. Gradually advance the level
of channel 2 until the desired effect is
achieved. If the level is made too high, the
level of the signal from the playback sonrce
will exceed that of the direct source from
channel 1, and the result will be feedback
and tape overload. This echo effect, no
matter how skillfully set up, cannot duplicate natural echoes, because there are only
two heads involved. The effect created with
this simple system is more of a vibrato than
a true echo, although, because of the time
delay and phase angle changes,. some illusion of echo is created. In order to create
a more realistic echo, additional playback
heads are often used. For good results, as
many as five or six such heads are employed, and are arranged on slides, so that
the spacing between them may be varied
for different kinds of effects. For the echo
effect of the mountains, for example, you
would need a fairly large space between
the record head and all the other heads.
These heads should be spaced so close that
the ear cannot perceive the break between
them. Each must have its own channel, with
the level of each succeeding channel set
just a little lower than its predecessor. •
AUDIO
•
AUGUST, 1957
, 0
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1957
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Nov. 1,2,3
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Nov. 8, 9,10
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Nov. 22, 23, 24
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37
CHARLES A. ROBERTSON '::
Coleman Hawkins: A Docume nta ry
Riverside RLP12-117 / 18
A good -three decades of jazz history in
this country and in Europe are touched
upon in this two-disc informal talk with
the man who did the most to make the
tenor saxophone the expressive instrument
it is today_ An evening of reminiscence
and anecdote in Bill Grauer's living room
has been edited into two hours of narrative, tracing Coleman Hawkins' story
from his birth on an Atlantic liner to the
present day. As the first such interview
designed for LP, it is illustrative of the
adventuresome spirit of the young men
at Riverside and invites a short sketch of
this growing company.
Formed less than five years ago by two
Columbia College classmates, it now
boasts a catalogue reaching from the
early days of jazz to the more advanced
modernists. It is venturing into the field
of folk music, the spoken word, and the
documentation of sports car racing. With
the move late this spring to a three-story
building at 553 W. 51st St., in the center
of Manhattan's record row, it is in a
position for continued expansion. Its beginning was somewhat less pretentious,
as told by Bill Grauer : "It is true we
started with a capital of $500. I don't
know how far it would take us today when
Paul Weller's photography and the artwork on one album runs to more than
that."
"Orrin Keepnews, my partner, and I
have never lost the love for jazz we formed
in college. Soon after graduation, I began to publish The Record Changer in
1948, while making a career in advertising, and Orrin took on the duties of assistant editor in addition to his work at
Simon and Schuster. With the development of the LP record, we saw the possibilities for economically reissuing rare
jazz items. Rights to the Paramount label
were leased and we set up shop on LaSalle St., in one room reuted from the
New York Theosophical Society. When
the floor fell three feet and rats began
coming up from the cellar, we took over
a store on West 49th St., which was overcrowded long before the move to our
present premises. Since then we have acquired a long list of defunct companies
and rights to player-piano rolls. Among
them are Black Swan, Gennett, Solo Art,
and Circle_ "
The new quarters afford ample space
for the staff of ten employees. Instead of
paper-laden desks, the executives have
private offices. "It has been reported that
we own the building," said Grauer. "We
* 732 The Parkway, Mamaroneck, N. Y .
38
are not that aftluent yet. But the groundfloor shipping room does include a garage
and workbench for the assorted sports
cars of the staff, anyone of whom is apt
to end the day in overalls on a tune-up
job. Barrett Clark, a former C.B.S. writer
in charge of our spoken word, is chief
mechanic and owner of a Jaguar XK.
Paul Bacon, art director, has a Porsche.
Harris Lewine, promotion director, rides
in a modified MG, and Ray Fowler, engineer, has a Renault. I drive a Maserati,
and Orrin still prefers to walk.
"With such a staff I have plenty of
support for the sports car series-my pet
project. Our trips to Sebring and Nassau
brought about some interesting engineering problems, especially as our approach
was different in each instance. At Sebring, we laid wires to various points of
the track and used a parabolic cone to
catch the race sounds. At Nassau, we depended upon portable equipment. The experiences of some of the drivers are being
taped for documentaries."
Asked about future plans, Grauer
stated: "They include full-length plays
and other projects for the spoken word
department. K en Goldstein produces our
folk music. He has done work for Tradition, Folkways and Elektra. We are not
in the classical or children's field yet, but
will be soon_ About the only things we
are not interested in are name bands
and pop singeI's_ They require the issuance of single records for proper promotion and we have no intention of doing
that_ Our first month in business netted
$275, now we are up to half-a-million a
year. Ours is tIle largest distributor setup
of any independent. We have thirty-seven,
and English Decca handles us abroad.
"The reprocessing of classic early jazz
recordings is continuing. We started the
year with the five-disc History of Classic
Jazz_ When we spot something in the traditional field that needs to be done, we
are ready to take it to the studio. Odetta,
a fine young folk-singer, does some early
blues in a manner wbich calls out for a
down-to-earth band. She will have one
when she records for us_ Right now, there
is more activity in the contemporary
field.' ,
Riverside is alert to the need to keep
up with the latest developments in sound.
The early reissues which built the company have been remastered in the past
year and given better surfaces. "Up to
now," said Grauer, "we have not pushed
our product in the high fidelity market.
From the beginning, we used Reeves
Sound Studios and nave been willing to
pay more than most independents to get
good engineering. It is not that simple
though. The results 'lVe want only came
wi th experience. The "Spectrosonic" label
is not a meaninglesB gimmick. It is used
only on those album.s with q? ality. sound
and is needed to aVOId confUSIOn WIth our
reissue series.
"To facilitate production, twenty-sixyear-old Ray Fowler was brought. over
from Reeves to become our staff engmeer.
He was trained for four years by Jack
Higgins and has charge of quality control from tape to finished record. We have
four machines for tape editing and turn
out two LP's every three days. The acetates 'are made by Reeves and checked before being Bent to Mastercraft Record
Plating. Masters are checked before they
are flown to California. Our search for a
satisfactory pressing plant ended in L os
Angeles. Considerable air travel is involved as a test pressing must be approved before the completed product is
flown back.
"On-the-spot sesBions have been made
at the Cafe Bohemia of Randy Weston
and Cecil Payne. Also some folk items in
Cuba. I don't know how much of this we
,vill do. They can be great and they can
be awful. We like to work with a purpose
and Bound in mind and find it can be best
accomplished in a Btudio. " With the release of a Hawkins' instrumental album
next month, I will conclude the Riverside
story in an interview with Reeves' engineer Jack Higgins.
The only previous use of the phonograph
record to document the career of an impOl·tant jazzman was meant for the archives of the Library of Congress. The
public was able to hear the irrepressible
Jelly Roll Morton's colorful tale of his
eventful life when Circle Records put it
on a serieB of early LP 'B. A word was
enough to Btart a fluent discourse on his
contributions. Coleman Hawkins had a
later, but no less vital role, and is much
more modest. When he met F letcher Henderson in 1923, the tenor s3.-"'{ophone )Vas
a stiff, unwieldy instrument of little jazz
consequence. In his decade with Henderson, he is credited by critics for singlehandedly making it a warm, full-blooded
voice, charged with rhythmic feeling.
Just how this was done is one of the
first questions that might com!! to mind,
and interrogators Bill Grauer and Paul
Bacon do not slight it when it comes up
in proper sequence. But Hawkins is unassunling in his claims and insists he was
kept busy staying ahead of a number of
good men. That he constantly listened to
other musicians is as much of the secret
of his genius as he is able to disclose.
The forging of various elements into his
distinctive style is described as "spontaneous," and that may be as much as
any jazzman can tell about what happens
between himBelf and his horn.
It is a question best answered as the
interviewers keep the discourse in a chronological channel and the whole picture of
the man gradually emerges. Too often
chance remarks of musicians are taken
out of context to gain wide circulation
before they can be clarified. Other interviewers like to ask the sort of leading
question which predetermines the answer.
Neither is possible before the eavesdropping tape recorder. Here some remarks
which might seem controversial in cold
print are immediately understandable by
the inflection of the voice. Other documentaries are in preparation, and in some
cases it might be wise for the questioners
to be more forward, following the informal portions with some questions in
the Mike Wallace manner.
Hawkins tells of the day when Jack
Teagarden and Jimmy Harrison met, of
his experiences in Europe and wit\l the
AUDIO
•
AUGUST, 1957
new generation on his return home. Many
jazz greats are m ontioned, but the listener
is likely to wish he could .inject a few
names of his own choosing, such as Benny
Carter, Lester Young, and Stan Getz. It
is perhaps significant of today's jazz
scene that the Hawk ends by casting a
wishful look toward a large band with
French horns and strings, and a more
realistic glance toward rock and roll. But
he shows he is still listening.
The Dukes of Dixieland, Vol. 3
Audio Fidelity AFLP 1851
Audio Fidelity usually times a new Dukes
pf Dixieland release for display at one of
the High Fidelity Shows. For the third volume the procedure was reversed, and it was
~~.~~ed~a~e!eh;:::rn~n
tt:sA!t~~~I::d:rh~o~~I~
It represents a desire on the part of pro-
ducer Sidney Frey for a program rich in
rousing march tempos, 'with ringing hrass
and singing clarinet well to the front. Since
the success of the first a lbum , he and Papa
Jac Assunto have planned the special effects
and arrangements which make this an outstanding sound and musical treat.
Some familiar tunes, and others not as
well known, are refurbished by ears attuned
to modern reco~ding techniques. The sound
of the band is more like those of the days
before dixieland went indoors. On some numbers, Stanley Mendelson's piano Is kept In
t he background, and the musicians playas
though they were back on the horse and
wagon with the tail gate let down. Newly
added drummer Stanley Ferrara sets a jaunty
. beat, to be reinforced by Bill Porter's walloping t uba, and they are oil'.
Each Dukes' album shows an improvement
over the last. T,'ombone1"'t and Lass1ts T"olltbone are brash exercises for the instruments
of Jac and Fred Assunto. My H01ne Town,
Scobey Str1tt and D,tkes Of Dixieland Ma"ch
are fresh material, but McDonough Let the
T"ombones Blow is Maryland, My Ma,·yland.
In the best tradition are Just a Close,' Walk
and B01trbon Street Pamde. For the most
suspenseful sound there is When Johnny
Reb Comes Ma"ching Horn e, with Frank Asc
sun to's galvanic trumpet solo. Clarinetist
Harold Cooper shines on With a Pack on My
Back. Eyes of Texas and Glory to Old Geo-r gia
fill out the bill. A stereophonic tape is available.
Art Blakey: Orgy in Rhythm, Vol. 1
Blue Note 1554
An exuberimt drnmmer who chafes unde r
the restrictions of the ordinary session, Art
Blakey is given the opportunity to expr ess
his rhythmic fancy without danger of splitting the seams of a small group. Gathered
about him are ten talented rhythm men and
Herbie Mann, who on this occasion brings
out his collection of African wood flutes, to
accompany the vocalists and set a mood.
'Working without a score and with no more
rehearsal than a short warmup period, the
percussionists u se their own language to improvise four numbers in the first volume for
a unique addition to j azz annals.
From his drum-seat throne, Blakey acts as
overseer, sings and leads jazz drummers Arthur Taylor, Jo Jones and Specs Wright, the
last two alternating on tympani. He also directs bassist Wendell Marshall, pianist Ray
Bryant and the flute. Sabu is in charge of
the Latin rhythm section, playing bongos
and timbales besides delivering the vocal to
the eerie Buhaina Chant. Potato Valdez and
Jose Valiente handle the congas. Machlto's
Ubaldo Nieto is on timbales, and Evillo Quintero triples on cencerro, maracas and tree
log.
Blakey first broached the plan for such a
session in 1954, but it could not be set until
this spring. And not because of any trepidation on the part of Blue Note to let a dozen
musicians loose on an untried idea, for Al
Lion had confidence in his house drummer
from the start. The result is the most exciting drum record ever made. Most such productions emphasize the role of the composer
in displaying the timbres of the percussion,
or feature well-rehearsed groups such as the
Steel Bands and the Gamelan Orchestra of
AUDIO
•
AUGUST, 1957
Bali. Here the communication Is instantaneous, propelled by the Inspirations of the section leaders and the daring interplay between
them.
Tofft, described as a song of hope, Is sung
by Blakey in African dialect, backed by a
chorus organized from among the musicians.
In the descriptive piece Ya Ya, a youngster's
feelings when kept from going out to play
are amusingly detailed in a manner to give
a chHd psychologist pause. Confined to the
jazz drummers, Split STeins places Blakey,
Taylor and Jones on their mettle as they
trade solos. It would be hopelessly redundant
to comment on individuals, but former Ellington bassist Marshall must be mentioned
for the way he copes with a difficult assignment.
The brilliant recording was made in an
Ilndisclosed Manhattan '" hall by Rudy Van
Gelder in an excursion from his Hackensack
stUdio. It presented the problems of a concert hall performance before an audience,
without allowing the engineer that excuse
for any shortcomings. Besides recording
countless jazz drummers, Van Gelder is responsible for Vox's Spotlight on Percussion
and in reply to my request for a few comments on the date said: "As we decided the
first take would be used on all tunes to capture the feeling of immediacy, I had to do my
planning in advance and make my recording
techniques fit the music. I was caught up in
the enthusiasm for the project from the
start and took a good part in the discussions
involved. The hall was selected for size and
shape to fit the requirements. My main problem was in picking up the singing while the
musicians remained at their drums. Luckily,
these aren't ordinary vocals so the result is
one of added depth and spaciousness. It is
based on my under standing of how drums
should sound on records. Personally, I am
most happy about it. It is also Blue Note's
first stereo tape."
A reduced edition of the Blakey percussion
group in more popularized exercises is on one
side of Columbia, CL1002. That the voices
are dubbed in, after being strained through
an echo chamber, removes it from consideration.
Freddie Kohlman: Jazz in New Orleans
M-G-M E3493
Municipal Auditorium in New Orleans is
the scene of this concert by the Mardi Gras
Lounge band , led by the veteran drummer
Freddie Kohlman. It combines the gusto of
Bourbon Street dixieland with some uninhibited swing-era soloing. Traditional numbers are J,tst a Close,' Walk, M i lenbm'g Joys,
and High Society, with Willie Humphrey
taking the clarinet chorus. Sid Davilla, clarinet, is featured in his original Ma1'di G-ras
Bhtes, and Sam Butera, tenor, is added for
Chl'istopher
Oolmnbus.
Thomas Jefferson
takes the trumpet part in I Can't Get Sta,-ted,
and Waldron Joseph's trombone is spotted in
Stom.pin' at the Savoy. Kohlman's vocalizing
is badly out of balance, but the rest of the
band comes through fairly well.
There are reasons
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Size: 9" x 9" x 6 Y4" high.
Dave Brubeck: Jazz Impressions of the
U.S.A.
Columbia CL984
The eight impressions are the result of
notebook scribblings made on tour with the
Quartet, and were recorded in New York,
Hollywood and the pianist-composer's home
in Oakland, California. The sltetches range
cross country from Broadway's Cm·tain Time,
to the piallo-solo Hom.e At Last. Plain Song,
a description of a bus journey, and Ode to a
Cowboy are westerns. Yonder to,' Two is an
essay in New Orleans two-beat, and Summer
Song is a cute vacation bit.
Joe Morello, former Marion McPartland
drummer, Is heard on record with the group
for the first time. He is a compelling add ition and makes Sounds of the Loop a percussionist's holiday on the El train. Altoist
Paul Desmond is his usual anemic self. Norman Bates plays bass.
A comparison with the Jimmy Guiffre 3
album is rewarding. Where one West Coaster
finds his way back to origins, Brubeck seems
to have stumbled across the pen of Ferde
Grofe in his travels. The viciSSitudes of the
road are great, but hardly that hazardous.
*Pat.
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Jazzville, Vol. 3
featuring
t.
- 1
8 hours play on
a 7" reel
The Jimmy Guiffre 3
Tandberg alone gives you the pleasure
of correct speed selection for varied
programs. Recording live music at 7 V2
IPS the Tandberg registers the full
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Foolproof operation permits changing
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Available in 2 or 3 speed models with
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Dawn DLPll14
Tbe aim of this series is to report tbe
rapidly evolving jazz scene in terms of outstanding performances by some of the younger
jazzmen. Vol. 3 is split between tbe Cbarlie
Smith Trio and tbe Aaron Sachs Sextet.
Smitb is a percussion special ist peculiar to
the present day. He bas always drummed
witb a trio or small group, rarely witb . a
big ba nd, Erroll Garner, Oscar Peterson,
Artie Sbaw, and Joe Busbldn bead the long
list of name performers he bas backed with
his impeccable technique. Now he works with
Dorothy Donegan, but is joined bere by Hank
J ones, piano, and Oscar Pettiford, bass. He
takes only one solo, in Flying Honte, being
content to provide a colorful backing to such
delicacies as the Jones' treatment of Have
You Met Miss Jones, and Pettiford's improvisation on'- Body and Soul. Also heard is
Bhies for Sal, by Thad Jones.
Sachs is a clarinetist who grew up in the
sh adow of Benny Goodman, but has successfully developed an original style. Tbough he
alternates on tenor, his heart is with the
clarinet, as expressed in tbe ballads You're
My Thrill, Why Shouldn't I, and Ah, The
Pa in. His ~barper tenor is heard on his originals Aaron's ' Bines and Platter P'ie. In tbe
sextet are the rap id-fire trombonist Jimmy
Cleveland; Dick Garcia, guitar; Joe Roland, vibes; Aaron Bell, bass; Osie Johnson,
drums.
TA'NDBERG
~
And it would be d.ifficult to find a publicity
man willing to write a more pretentious set
'o f liner notes tban penned by the composer.
Tbe juvenile History oj a Boy Scout is billed
as a bow in the direction of Stravinsky's
Histo·i,·e D 1t Soldat. It is more on tbe level of
Parade Of the Wooden Soldiers. ' Tbe sound
ranges from good to a poor recording of the
solo.
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that the high frequencies are distributed over a wide angle. An excellent choice for industrial, school and
home applications where space is at a
premium and tastes in musical and
spund reproduction runs high.
Atlantic 1254
Jazz instrumentation has become so varied
that there is little left in the way of surprises. Still, it may take considerable trial
and error before a combination is found to
su it tbe special talents of a musician. In the
past few years, Jimmy Guiffre bas developed
a bighly personal clarinet style, marked by
a breathy tone and a subtlety of vibrato and
dynamics, the values of which are easily obsCUl'ed in the wrong framework. He seems
to have found the right setti ng in this trio,
where he bas the good fortune to be complemented by a lyric guitarist in Jim Hall
. and a rbythm ically secure bassist in Ralpb
Pena. All speak witb an equal voice.
Furtber, tbirty-six-year-old Guiffre uses his
growing talent as arranger-composer to aerate
some murky corners of jazz. Seven of the
nine selections are of his own composition,
and are mostly a . refreshing treatment of
blues themes. The West Coast scbool is notable for tbe refinement of such materials
into a bland, cerebral mixture. Guiffre reverses this trend by going back and re-exa mining origins, allowing the springlike
breeze of folk music and spirituals to blow
an old-time flavor through bis tunes.
The train theme is a recurrent one in folk
music and jazz, from Meade Lux Lewis'
Honky TonI, T"ain B!ues, tbrough Alabamy
Bonnd:, to Nancy Wbiskey's skiffie-group rendition of Freight Trai n. In his The Train
and the River, he plays baritone, tenor and
clarinet over the high-wbeeling rhythms to
mal,e a last ing contribution to this literature. In Orawdad Suite and T100 Kinds of
Blues, he uses the device found in some
spirituals of contrasting two different moods.
In sum, tbe album is an appealing compilation of moods, arising from tbe fundamentlils
of jazz and permeating even tbe ballads
T l~is Is You, My All and That's the Way It
I s. Guiffre pencils a laconic set of liner notes,
as direct to tbe point as one of his solos.
Model 165BK ............ $66.50
Complete specifications on request.
On demonstration at our studio.
Mail orders filled. 25% deposit, halon« C.O.D.
.E:nNARD
~
40
6q ( ...
' Io"rll~' N ~_
RADIO. INC.
YM 7, N. Y. COrtI. ... 7-OJ11
Hank Mobley and His All Stars
Blue Note 1544
In one of h is infrequent holidays from
tbe Modern Jazz Quartet, Milt .Jackson gives
his vibraphone a vigorous workout with an
imaginative rhythm section. And he swings
from his first unison chorus with tenor man
Hank ~Iobley in the convivial uptempo Re-
The prog.-am consists of five Mobley
originals. The diffuse U lt"a1ltal-ine and the
gay Don't Wa!k are warmups for the fine
blues Lower St,·atosphe,·e, which has the most
expressive solos and would benefit from a
few more choruses.
lIIobley is beard to best advantage in the
sensuous Mobley's Musings, a mellOW, romantic showcase for his horn. On drums,
Art Blakely is more subdued than usual and
Doug ,\Vatldns, bass, deserves more solo
space. Pianist Horace Silver's' performance is
happy and spontaneous. Given a cbance to
stretch out, Milt drives his vibes witb an
intensity less productive "of : tbe " best sound
than of a throbbing rhytbmic line.
111tiOIt.
Buddy Collette: Nice Day
Contemporary "C3531
For the past seven years Buddy Collette
has lent bis talents to the Groucho Marx
radio and television shows, enjoy ing a freedom to play jazz with bis own groups and
as a sideman for recording sessions. He exh ibits a flawless lucidity on four instruments, projecting an aura of effortlessness
which might pall without a creative flair
for tbe unexpected. He plays clarinet on four
numbers, alto on three, flute on two. tenor
on one. Different rhytbm sections support
him on three separate dates.
Five originals show his gift for simple
impressionistic sketches. His clarinet on A
Nice Day, his alto on Change It, and his
flute on Fall Winds, makes them things of
growing beauty. Collette avoids tbe misstep
or meaningless complexity wbicb could destroy tbem. Pianist Dicl< Shreye is credited
with 'Minor Deviat ion, a blues for clarinet,
and contributes a telling solo to Blues for
Howard:. Other rhythm men include Calvin
Jackson, Don Friedman, Leroy Vinnegar, and
Sbelley lIIanne in a fine recording by Roy
DuNann.
Solo Flight
Jazz West Caast JWC505
Eleven musicians are given ample solo
space on ten numbers ' in this well made
package by an offsboot of Pacific J azz. The
sampling ranges from the veteran Harry Edison's trumpet on September In the Rain
to the newcomer James Clay, whose tenor is
introduced on Itt a Senti'menta! Mood. This
twenty-one-year-old discovery from Dallas,
Texas, has an uncompromising, muscular
style of great promise. Ballads compl"ise the
bill of fare, offering sucb diverse talents as
Art Pepper and Lee Konitz on altos. Also
Bill Perkins, Richie Kamuca, Chet Baker,
Bob Brookmeyer, Bud Shank and Pbil Urso
with compatible rhythm sections. A pastel
drawing by the Los Angeles artist John
Altoon is on the cover.
Jonah Jones: Muted Trumpets
Capitol T839
As one in the vanguard of tbe visitation
of swing to 52nd Street, Jonah Jones made
bis stand with Stuff Smith at tbe Onyx Club.
A good twenty years later bis smart. up·
dated swing is to be found a few blocks
across town at the less boisterous Embers.
His muted shading of a tune and his brassy
trumpet accents make him an enduring figure. The ten numbers span the years from
Royal Ga"den Blues to On the Street Wh61'e
You Live and the main theme from Man With
the Golden Ann. His vocal on Ma ck tfie
K ..i.je is in a class with Armstrong's. George
Rhodes, piano; John Browne, bass; and Harold Austin, drums ; remain in a tasteful balance wbich must have made the eng iueer's
task a pleasant one.
Mat Mathews: Four French Horns
Elektra 134
That the French horn does not enjoy a
more prominent position among jazz musicians is not because of any reluctance on
their part to further its growth. They admire
its sonorous sound and rounded tone, but
are aware of the difficulties of making it
move with jazz feeling . .JuliUS Watkins, coleader of Les Jazz Modes, and Dave Amram
are among the few whOMbave surmounted
this obstacle and · can convey the urgency of
swing on the instrument. So they were the
first to be called upon when Mat Mathews re-
AUDIO
•
AUGUST, 1957
solved bis desire for a date witb four F rench
horns, supported by bis accordion a nd Joe
Puma, gu itar ; M'lt Hinton, bass ; Osie Joh n·
son, (l1·ums. Studio men Tony Miranda and
Fred K lein complete t he hom section.
Mathew's conception proves to be a stu n·
ning use of the contrasting tonal qu a lities of
t he horn, plus the harmon ic a nd uni 'o n
values of the section a s a compleme nt to t he
soloists. He avoid s t he pretentious in h i ~
playing and in hi s alTangements of Com e
Rain or Corne Sh in e, On the Alamo a nd J
Want To Be HaplJY, s tl'ess ing br igh tness a nd
mobility. His two origina ls featuring Hi n t'on
on a blues theme, and Puma on Span:sh
guitar, furth er secure hi s status as a tasteful
writer. Wa tk ins, Amram a nd P uma each
supply one tune and are superb as soloists.
Recorded by Dave Hancock a nd Leonard
Ripley, the timbres of the horns make it t he
most satisfying item soundw :se in t he label's
new jazz catalogu e.
Sonny Rollins
Blue Note 1542
When a j azz mn SICla n co nsolidates his in·
fl uences and begins to mO\'e ahead on his
own, he enters a s ta ge of h is de\'elopment
of mos t interest to the stud ent of jazz. Since
he left Chicago in early 1956 with t he lIIa x
Roach group, twenty·seven·yea l··o ld So nny
Rollins has gone through su ch a ph ase to
become the most important new voice on the
tenor saxophone. And there is no indi cat ion
in this representative album t hat h is g rowth
is not going to continue. The four origi na ls
display his restless, incis ive sty le at length.
D ecision is a minor blues t heme, 13 ba l's long
instead of the traditional 12, and is followed
by the medium·tempo BI1£esnote. Plain Jane
and Sonnysphe" e are fleet exercises, the latter
containing bits of I Got Rhythm and Honey·
This is the n ew
THE AUTOMA T IC
The problems of dust, lil1t, aHd static (' r,rildllp 011 phol1ograph records and pickup styli have
been solved by this iHgenious /l ew inven tioH which cleans the record as it is being played. T he
plu;h pad, mounted 011 its own arm (above) , is slightly moi5tel1ed with the special, harmless
activatiHg flUid supplied in a replaceable applicator. T his helps to loosen groove dust aHd
dirt, which is thel1 collected by the nylon brush aHd pad. It also eliminates the static charge
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one hundred times duriHg a single play . Ol1 ly $ ~ . 75 complete with fi ~rid!
Electro:"SoI11'c Laboratories, l11c.
suckle Rose.
Dept. A • 35-54 Thirty-sixth
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I'
His slowly unfolding treatment of th e ba l·
lad How A1'e Things in Glocca Mon'a is an·
other part of h is personality. In the close
recording, he broods over it as searchingly
as Coleman Hawkins m ight, wringi ng out
every drop of sentiment. ' Vhen some com·
pany prevails on him to embroider enough
ballads for an album , he is certa in to reach
a commercial success that wi ll di s may h is '
jazz fans. In th e admirab le qu intet, Donald
Byrd plays trumpet ; Gene Ra mey. bass;
Wynton Kelly, piano ; Max Roach , drullls.
FOR
AUDIO
•
AUGUST, 1957
ITS
BEST
The book you have waited
for so long-
EDGAR M. VILLCHUR'S
HANDBOOK OF
SOUND REPRODUCTION
For ove r two years. th is material ran in consecutive issues of AUDIO and was followed
avidly by every reader. Now available in
book form w ith corrections and minor revisions, this material w ill be recognized as the basis of a thorough course in sound reproduction. Covers the
subject from the e lements of sound to ind ividual chapters on ea~h of .the
important components of a sound reproducing system . Ready for Immediate
delivery, $6.50 postpa id (Fore ign , $ 7 .00 postpaid ).
Customary discou nt s to dealers and d istribut ors
Quintet of t he Hot Club of France : Swing
From Pa ri s
London LL 1344
T h e Quintet of th e Hot Clu b of France hil S
a secure place in ja zz h isto ,'Y as t he fi rst
of the mode rn chamber groups and as t he
first European group to draw ·t he admiration
of American musicians anel critics. It is notable for the presen ce of Dja ngo Reinhardt,
t he incomparable gy psy guitarist, who did
much in its pre-electJ'ic days to free hi s instrument f rom its lim ited rhythm role. In a
dozen numbers reco rded be tween 1937 and
1939, his technical Sl(ill stands up to the
test of time. The t ~ n se swing of Stephane
Grappelly is less ind es t ru ct ible. but ha s yet
to be s urpassed by Illlother violini st. Superior
sound fo r t he per iod .
•
AT
AT LAST!
The Gerry Mullig-an Quartet
Pacific Jazz PJ1228
A pause in the tra \'els of the GeL'1'~' Mulligan Qu a rtet permitted this poten t record ing
last December in the precincts of Boston's
Storyville. Though there a re some introspective moments, any lass itude on the a udience's
part is dispelled by the holiday gaiety of fou r
of the originals. Bob Brookmeye r's RI/sti.c
Hop is a bucolic romp and, on hi s Open
Oountry, his valve trombone would rejuvenat e
a flagging B roadway chorus line. Mu ll igan's
Bweebida B100bbida is a stimulating excu rsion
for h is baritone sax, a nd Bike U p the St1'and
is a memento of hi s recent European tour.
Another facet of t he Mulligan per sona lity
emerges as he utilizes the p iano in the reo
vealing blues study StOl'yv i!!e Story. The
standards B 'i1·th of the Bines, Baltbles, Ban·
gles, and B ea(ls and 7' hat Old Fe eling are
projected in the concentrated form of com ·
munication that makes 1'01' t he beRt cha mbe,'
jazz. Rhythm men nre B 'II Crow, bass. nIid
Dave Bailey, drum , . Pnther Norman O'Co nnor examines the emot'o nal ties between jazz
and modern a rt in t he line r no tes.
L I STENING
RADIO MACAZINES, INC ., Book Division
P. O. Box 629. Mineola . N. Y.
Please send me . ... .. ... .. copies of Villchu r's HANDBOOK OF SOUND
REPRODUCTION . I encl ose check 0 money order 0 fo r
$6 .50 each .
Na me
...... .. .. . . , , . .. ... .. . . . .... . .... . ..... . . . . . . .... .... .... . ...... .
Address . ..... . ...... . .. .. • .. . . . ... . ... . ... . ... ... . . ... .. •... . . . . . •. .. .. .
City . ...... . ...... . .. ... . . . . . . . . .. .. Zone ...... St ate .. . .. . . ..... .. .... .
41
INTERMODULATION
(from page 25)
"Are you Boom Conscious?
MOlt people bow by this time that many,
if DOt - . loudspeaker enclosures ••• Ieor price • • • boom. Boom ia
iUt duD, heavy, toDe1_ thud often heard at
low freqUencia. Boom ia also C:alIed "ODe-DOte
baa" or "{uke box baa." It ;. aD iDhereDt
characteristic of so-called "reaonant"enclolureS. Boom ia nothilag but diatortionJ aDd aDy
Ipeaker system that bOoms ia not bigll fidelity.
NotwithltancliDa this. aDd believe it 01' -.t.
there are .till people who will ~nd hnndreda;
and eventhoulaDda, of doDan for. prime _pli&en, tnDen.l.~~' aDd then SO out and boy a
boom-box. nllY?
.
A DOted psychiatrilt undertook to &ad the
answer. He found that (1) some people mistake
mere Ioudn_ (so-called "auplented" bus)
for true baa; (2) others are uDable to teI1~
dif[erence between true bus aDd boom;
_ e think boom is bus; (4) others
boom ia basi beeause it comes from I!UP
and/or ex~nsive endos~i (5) others haVe
• IDation for expirins mJUII, such as "the
biger the box the better the aound,l; (I)
some innately reaiat progreu aDd never _m
able to adjust themselves to better thiDp as
they come along; (7) others are im~ by
.....u- of size
••
elIpensive advertiaiag and bigh-preuure aa1ea
promotion.
And 10 it goes, even thought. actna1ly, 110
one ever heaid boom from a live orchestra.
And since .a live orchestra ia DOt a boom-bos,
why should anyone want a boom-box in hi.
home? FOI'tuDately, no one baa to buy • boom-
bOX.
To those who want live-music facaimiIe instead of boom, competent lound~. UD
. •
• ocaU recollD'Daid THE BRADFORD
~~ BAFPLB. rr DOES NOT BOOM
• • • EVER.. The reault ia ,~ true baa.
Thia ia accomplished by a newt patented device
hued upon a scientific prinCiple. It ia not a
baa-re8ex or folded hom.
Moreover, it aatia6ea everJ. other criteria of
the diacriminating audiophile: Com~""u;
12" x 12" x 9" for II and lOa' 17" x 17" x 14"
fOl' 121 and 151. Firs." Co~'ioll .n4 FirIiIIa;
%", genuine mabo~y, korina blond. walnut
aD ebony veneers; aDd imfiniahed birch. B~oll­
omy; from $54.50 to $69.50.
II )IOU Gf'. boom "orunow,. _III IiCl._","
luli..w.
jru,."
,Ito" ,,"",wm.
,....."rn'oliln
..6.u
'0 0/ II.Gln
..
,lauds, /aU
'ur••
)lour
or
BRADFORD & COMPANY, 27 East 38th Street, New York 16, N. Y.
would narrow down the intermodulation
distortion components considerably.
These components can be further narrowed down when it is observed that
higher order sidebands and harmonics
are outside of the audio range of 20 to
20,000 cps. For this discussion, it will be
satisfactory to use the two fundamentals
and their sidebands as the sole factors
contributing to intermodulation distortion. In the meantime, it should not .be
forgotten that this all encompassing feature of 1M is that it gives excellent correlation with listening tests.
The exact process for the creation of
a variation in the amplitude of the highfrequency wave due to the modulation
by a lower frequency can be seen in Fig.
4. Here, the high frequency is superimposed on the lower frequency in the grid
input circuit. Due to the nonlinearity of
the grid input voltage to plate output
current characteristic, there is a variation iii the high-frequency amplitude in
the plate circuit of the tube. The resultant amplitude of the high frequency
component is shown below the output
wave as a modulated signal. The analysis of this signal is indicated under
MODULATION above.
Testing for Percentage 1M Distortion
-' TAPE
RECORDERS
TAPE
AND
RECORDINC
By
Harold, D. Weiler
Author of
"High Fidelity Simplified"
The first complete book for the home recordist. Tells why, how,
and what in easily understood language-not too technical, yet
technically accurate. Covers sound, room acoustics, microphones, microphone techniques, editing and splicing, sound
effects and how to make them, maintenance, and adding sound
to slides and home movies.
RADIO MACAZINES, INC., Book Division
P. O.
BOll
629, Mineola, N. Y.
Please send me •••••••••• copies of Weller's TAPE RECORDERS AND TAPE RECORDINC. I enclose check 0 money order D. 0 Board cover. $3.95.
paper cover, $2.95.
o
Name
Add,..
City
42
.................................... .. ........................ ..
Zone ...... State ........... . .... ..
There are two general standard methods used for measuring intermodulation
distortion. The first, known as the
SMPTE method (Society of Motion Picture and Television Engineers) mixes
two sine waves in an ampliifier. A low
frequency, ranging from 50 to 100 cps
is ~ixed with a high frequency of about
7000 cps, and fed together into an amplifier. The ratio of the amplitudes of the
lower frequency to the higher frequency
is fixed at 4: 1. The resulting degree of
modulation determines the percentage
of intermodulation distortion present
in the amplifier under test.
A second method in use is the CCIF
test (International Telephonic Consultative Committee) . Here, two signals of
equal amplitude are fed into the amplifier under test. The two signals have a
small difference frequency such as 100
cps. Thus these signals can be 7000 and
7100 cps or 8300 and 8400 cps, and so
on. The resulting difference frequency of
100 cps due to non-linearity is the measure of the percentage of intermodulation
distortion.
Both methods of measurement are useful in their own spheres.
Amplifiers exhibit different amounts of
nonlinearity at different parts of the
frequency band. Since the CCIF method
measures the low-frequency distortion
component due to the distortion in the
higher frequencies, the nonlinearity at
AUDIO
•
AUCUST, 1957
tju!se higher frequencies of the audio
spectrum is observed here.
The SMPTE method utilizes a strong
low-frequency signal and a weak highfrequency component. The difference frequency is of a high order of magnitude.
Thus, this method will indicate the effect
of low-frequency nonlinearity on a high
frequency.
Another' Teason w hy today's
fastest selling high fidelity
Te coTd changeT is
Equiv·alent Sine Wave Power
*
This derivation assumes the use of the
SMPTE method where two signals with
amplitude ratios of 4 to 1 are used.
Assume a signal of 1 volt is superimposed on a signal of 4 volts. The peak
voltage applied would then be 5 volts.
(See F ig. 5.) Since power is proportional to the square of the voltage (P =
E2 /R), the equivalent power output is
Accurate Speeds-
f ac to r y pre-set a nd tes ted
for less than 0.25 % rms wow and
flutter content measured
at 33 \~ rpm ... s pecifications unll1 atche<\
in t he field.
H
For other features and new popula r p rice, see your
h i-fi dealer or write Dept. A-OS
650 Halstead Avenue, Mamaroneck, N . Y.
Fig . 5. Waveform of a l-volt high-frequency signal superimposed in a 4-volt
low-frequency signal. This is the usual
form of intermodulation test signal.
proportional to (5/4 )2 times the power
at the 4-volt output.
The r eal power output is not the peak
power. Both frequencies deliver their individual amounts of power to the amplifier's output. The true power output is
actually the sum of the powers deliver ed
by each frequency component. In thi~
ease, the output power is proportional
to (4 volts)2+ (1 volt)2 .
However, distortion r efers to the peak
power output which is proportional to
52. The ratio of the peak power to the
actual power is 5 2/(42+12) =25/17, or.
1.47. Thus to find the peak power, the
actual power indicated on the meter
when making the intermodulation test
is multiplied by 1.47. Amplifie.rs are
rated at this peak power, commonly
call ed "Equivalent sine-wave power."
This refers to the power in a sine wave
signal whose peak voltage equals thp
peak voltage of the 1M signal.
Typical 1M Analyzer
Figu1'e 6 shows a theoretical schematic
of an 1M analyzer and the method by
which it operates.
(A) shows two signals h aving an am plitude ratio of 4: 1 combined and fed
into the audio amplifier. Coming out of
AUDIO
•
AUGUST, ],957
TH E OU ESTION:
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:
ECTRoDEX
FORMERLY
MDIOFILE
Not a new publ ication, but one which for over 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 which may be kept as a permanent record of all electronic periodical
lite ratu re.
LECTRODEX-the electronics index-is now published by Radio Magazines,
Inc., and has been expanded to include the contents of twenty magazines in
the radio and electronics fields. Sold by subscript '?n only, $3 .00 for one year,
$5.50 for two years. Back Annual issues are available from 1946 through
1955, 50¢ per copy. Subscrib, now and know where to find the information
you often need so badly.
RADIO MACAZINES, INC.
P. O. Box 629,
Mineola, N. Y.
43
SAVE
AUOIU_
t •••• , . , • • • •
250/0
This is our
GROUP SUBSCRIPTION PLAN
Now you , your friends and co-workers
can save $1.00 on each subscription
to AUDIO. If you send 6 or more subscriptions for the U.S., Possessions and
Canada, they will cost each subscriber
$3.00 each, V4 less than the regular
one year subscription price. Present
subscriptions may be renewed or extended as part of a group. Remittance
to accompany orders.
modulating low-frequency component is
left. This component is a measure of the
actual amount of intermodulation distortion created by this amplifier. Feeding
this signal to the VTVM, and comparing
this with the original amplitude of the
modulated signal, indicates the percentage of intcrmodulation distortion.
To specify 1M distortion by itself is
not enough. The method used for t esting
is significant. 1M distortion measured
by the SMPTE method below about 2
per cent cannot readily be detected by
the ear. Valves measured by the CC1F
method can not be related directly to
those obtained by the SMPTE method.
To describe fully the distortion present
in an amplifier, both harmonic and 1M
distortion tests should be made.
the audio amplifier are the two signals
modulated, with the amplitude of the
h.ig.h.-freq.u ency signal varying ill accQrdance with the low fTequency. The highp ass filter in the analyzer eliminates the
low-frequency component and passes
only the high frequency which has a
low-frequency
amplitude
variation
caused by the distortion in the amplifier.
This modulated signal is used to set the
reference voltage level for a vacuum-tube
voltmeter. The modulated signal then
passes through a detector similar to that
found in a radio receiver. The resultant
signal is the low-frequency component
which originally modulated the high
frequency. The low-pass filter bypasses
any of the high frequency left after detection, with the result that only the
60-CPS S)NE WAVE SIGNAL
4. (FROM OSCILLATOR
OR POWER LINE)
INPUT
AUDIO is still the only publication
devoted entirely to
AMPLIFIER
•
•
•
•
•
•
•
Audio
Broadcasting equipment
Acoustics
Home music systems
Recording
PA systems
Record Revues
(Please
------
SIGNAL GENERATORS
Signal from amplifier.
High frequency superimposed
on low frequency .
TO INPUT OF
ANALYZER
(A)
Detected signol .
low-pass filter.
Onl y high frequency
of v o~yin9 magnitude
Low frequency left .
Some high frequenc y
component still in
I.ft .
Filtered output. No
high frequency. Onl y
low Frequency left.
signal.
print)
Name
Address .. .. . .. ................• • .. . .
o New
.. • •.......
0 Renewal .. . .... .
Name . ... .• .. .•• .. .....•• . ... •... ..
Address .. •...........•. . .........•..
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0 Renewal ... .. .• .
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Address ............... .. .•••..•. • •• •
o New
. . .... ..... 0 Renewal . . ....••
~II-_--+-
INPUT TO
ANALY ZER
SET LEVEL
Name . . •.. . .. . .•.............•. .. . .
Address . .... .. ..... •• .. . . •• ........•
VTVM OR
o New
.... .... . ..
0 Renewal . . . . . •..
Name ..... . . . .••.. .. .. .•..........•
Address ........ ... •.....• .••. . ... •••
o
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...•....... 0 Renewal •. .... ••
U. S. , Possessions, and Canada only
RADIO MAGAZINES, INC.
P. O. Box 629, Mineola, N. Y.
44
Fig. 6 . (A) Arrangement of generators and amplifier for making 1M tests. (B) Simplified schematic of 1M analyzer. The percentage of 1M distortion is equal to 100 x (output voltage/ set-level voltage).
0 Renewal ••. .. .•.
Name ... ... ........ . . ..... .. ••• .. ..
Address . . •... • .. ..... . . ........ ..• •.
o New
EQUIVALENT
(8)
TREBLE AMPLIFIER
(from page 16)
marginal rating for a given job will be
overloaded when RC filtering is employed.
The resistor labeled R in Fig. 5 must
be chosen so that 260 v.d.c. is delivered
to the amplifier. One may not be l'e-
quired. Positive heater bias of one-tenth
the plate voltage is provided by the
bleeder network. The bypass capacitor
grounds the center-tap of the 6.3 v.a.c.
winding to audio frequencies and must
not be omitted if hum is to be minimized.
AUDIO
•
AUGUST, 1957
Conclusion
The writer is of the opmlOn that a
high-quality playback system requires
the employment of a dual-channel amp lifier. A high-level dividing network
cannot opel'ate satisfactorily unless each
filter section is terminated in a pure
r esistance of appropriate value. The
driving-point impedance of a speaker
is complex and functionally r ela ted to
frequency. It may be predominately reactive a t some frequency in the pass
band. This accounts in part for the fact
that dual loudspeakers employing highlevel dividing networks do not always
so und right. Constructional details covering an excellent dual channel amplifier
were presented in reference 1. The use
of the treble amplifier described in the
present article will reduce the cost of
the system with no sacrifice in performance. When used to drive the writer's
speaker,4 which is located in a room of
modest size, the obtainable sound intensity level approaches the thre,s hold of
pain over the entire frequency range of
the speaker.
The availability of a high-quality sin4 Charles W. Harrison, Jr., (( Coupled
loudspeakers," 3rd Audio Anthology, Radio
Magazines, Inc. (1955) pp. 101-105.
gle-ended: transformer makes it desirable
to re-examine the utility of single-ended
amplifiers for high-fidelity applications
when high power output it not a requirement. The advent of tubes with high
transconductance, such as the Mullard
EL-34 and Tung-sol 6550, which result
in high power sensitivity and low drive
requirements, makes it highly desirable
for transformer manufacturers to produce a line of transformers capable of
carrying th e plate current in the primary
winding and that are comparable in
p erformance to those manufactured for
push-pull application. It should be possible to obtain easily 10 watts of power
output from a single-ended amplifier
employing only two stages. The circuit
is not complicated and there is no requirement for a phase splitter. Large
values of negative feedback may be applied and the amplifier will r emain unconditionally stable if the output t ransformer is properly designed. Admittedly,
it is somewhat more difficult to design
a good transformer for single-ended output stages than for push-pull application. But the Triad Transformer Corporation has made a good start in producing the model HSM-79 transformer, and
this should serve as a challenge to other
manufacturers in this field.
•
How to
increase and enrich your
understanding of music
In this stimulating new 'book for th e layman
who wants to understand music more fully
for complete listening enjoyment, the author
shows you plainly how to evaluate your musi·
cal impressions and how to discover the spe·
cific musical elements and processes which
create them. Filled with musical examples,
the book provides tools for analyzing, evalu·
ating, and appreciating music of all periods.
Just Out!
MUSIC:
The Listener's Art
By LEONARD G. RATNER
Professor of Music, Stanford U.
370 pages, 6 x 9, 158 Musical Excerpts
18 illustrations, $7.50
T soundHE qualities of
how loud or
strong, what level or
pitch, and the special
colors -- are presented
through the analysis of
works of such compos·
ers as Beethoven, Ravel,
Mendelssohn, and Mo·
zart. Next the move·
ment of musical sound
is assessed-how fast,
how smooth, how regu·
lar or irregular, how
gentle or forceful. The arrival of the move·
ment itself-gentle, forceful, clear, doubtful,
tentative, final-is also discussed.
Once acquainted with the devices used by
composers to stir the listener's feelings and
senses, you are introduced to music through
the ages, with explanations of how musical
forms have evolved from the earliest medi·
eval plain song to modern experimental
compositions.
Contents
1. The Musical
Fig. 5 . Power supply featuring
RC filtering .
AUDITORY PERSPECTIVE
(f1·0m page 21)
loudness difference into a given angle,
even though the difference is produced
by a combination of similar sounds from
several directions, the angle from which
the reproduced sound seems to come can
be obtained from the computed loudness
difference by reference to Fig. 3.
To verify this theory for a two-channel
system, lines were drawn on the pick-up
stage representing a constant distance
r atio to the two microphones. These
curves are shown on Fig. 4. Since the
ratio of the distances to the two microphones along anyone of these curves is
AUDIO
•
AUGUS.T, 1957
a constant, the difference in level at the
microphones of ai sound produced along
on anyone curve will also be constant.
This difference 'in level, which is marked
on the curve, will be can-ied. through to
the loudspeakers and 1vill cause a difference in loudness in the two ears of a listener.
These differences of loudness in the
two ears of a listener were calculated
for a listener position along the center
line of the auditorium and a distance in
front of the stage equal to the separation
of the loudspeakers. From these calcu-
Experience
2. Musical Elements
and Their Relation·
ships
3. Medieval 1\1 usic
4. Renaissance Music
5. Baroque Music
6. Classic Music
7. Romantic Music
8. Modern Music
9. Retrospect
SEE THE BOOK 10 DAYS FREE
RADIO MAGAZINES, INC.
P.O. Box 629, Minneola, N. Y.
Send m e Ratn er's MUSIC fo r 10 days'
examination o n a pproval. In 10 days I will
remit $7.50 plus few cents for d eli very
costs, or re turn book postpaid. (,",' e pay
delivery costs if you I-e mit with this coupan; sa m e ret urn privilege. )
(Print)
Name
Address
City ,
Z one
Sta~c
C ompany
Position
45
silence
startling
for the perfectionist
.~
O~LE
,T he hush of an empty church, evet, . hough
the synchronous motor ill running - this is
the Connoisseur, crafted in traditional
English quality. Precision machining assures
pure sound reproduction. Non-magnetic, 12"
lathe-turned table; precision ground spindle;
phosphor bronze turntable bearing; ±2%
variation provided for all 3 speeds; hysteresis motor.
$110.00
TURNTABU: Rumble-better than 50
db down ; Wow-less than 0.15% of
rated speed ; Dimensio ns : 131hx15%.".
PICKUP: F requency Response - 2020,000 cps ±2 db at 33 % rpm; E ffect ive Mass- 4 mg ; Impedance-4 00
ohms a t 1000 cp s.
"Dynabalanced" tone arm w ith Mark II
super -lightweight pickup
w/di a mond stylus
$49.50
wjsapphir e stylus
$34.50
Write toda1/ for literatur e.
ERCONA CORPORATION
(Electronic Division)
551 Fift h Ave., Dept. 83, New York 17, N. Y.
In Canada : A stral Electric Co. L td.
~4 Dan fo rth Road. Toronto 111
Circle 46A
_,
fJJj AI
1. -
....
9
.,\':: I
12 ,
11'.
O
15.
.
7, 13.
~fb...'
~
14. ""-'
6.
GIBSON GIRL (jj) TAPE SPLICERS
I. Semi. Pro
SP·4
S 3.50
2. J unior
TS·4J R
6.50
3. Sta ndard
TS·4STD
8.50
4. De luxe
TS·4DLX
II ,SO
5. Indust ri al (5 size·s to I" )
(n et ) 55.00
ROBINS PHONO AND TAPE ACCESSORIES
6. Sp li c ing tape
ST.. 5OO
$ .39
7. Jockey C loth fo r Tapes
JCT ·2
1.00
8. Tape Th rea der
n ·1
.98
9. AUD·O· FILE
AF·50 (net) 23 .99
10. Cha nge r Cove rs
CC· I 2
2 00
II. Tu rntable Cove rs
CC.3'
2'50
12. Di sCl osures
EIO , 12 (p kg) 1:20
13. Jockey Cloth for Records JC· I
1.00
NB · I
150
4. Klee NeeDLE,
5. Pho no·Cu shion. 10", 12" PC·IO 12
I'SO
6. Atom ic Jewel
SE·90 '
5:00
At
46
Circle 468
lated differences in loudness in the two
ears and Fig. 3, the angle from which
the sound should apparently come was
obtained, and these angles are also
marked on the curves. A person speaki ng
anywhere along the curve for a 6-db level
difference, therefore, should appear to
the listener to be at an angle of 15 deg.
Actual tests bore out this relationship
fairly closely. Moreover a speaker on the
6-db curve, appearing 15 deg. off the
center, would appear to the listener to
move to an angle of 8 deg. if the difference in level was decreased to 3 db by II
manipulation of the amplifiers. I n fact
many of the effects of walking about the
stage can be duplicated by volume manip ulation as the person speaking walks
back and forth along the center line of
the stage. Although the observed and
calculated angles agreed fairly well for
central observing positions, the apparent
source shifted more rapidly toward the
nearer loudspeaker than computation
predicted, as the observer moved toward
the side of the auditorium.
Similar curves were calculated and
tried out for a three channel system, and
a similar correlation of observed and
calculated positions was found.
These curves were all calculated 0 11
the basis of sound of equal quality at
the two microphones. If the quality di ffered materially-if one microphone
picked up mostly direct sound and the
other reverberant sound, for examplethe localization by the observer would be
quite different. It was found, for example, that if the right microphone
p icked up mostly direct sound and the
left, reverberant sound, the sound would
appear to come from the right loudspeaker until the level of the left
speaker was raised 10 db. In general the
localization tends toward the channel
giving the most natural 01' close-up reproduction.
These tests, proved conclusively that
very good localization could be obtained
by a three-channel system, and that twochannel reproduction gave good angular
localization although the distance locali zation was not entirely satisfactory f or
central positions. In the application of
auditory perspective to the r eproduction
of orchestral music, the satisfactoriness
of the two- and three-channel systems
is even greater than indicated by the accuracy of the localization. The enhanced
aesthetic appeal obtained from an auditory-persp ective reproduction of an orchestr a is not due so much to an accurate
localization of the various sounds as t o
a general effect of space distribution,
which adds a f ullness to the over-all
effect. For this reason either two- or
three-channel reproducti(}n in auditor y
p er spective is very satisfactory f or orchestral r eproductions.
"'--CLASSIFIED---'
Rates: lO¢ per word per Insertion for noneolllllnial
advertisements; 25¢ per word for comm.,.lal
tls.ments. Rates are net, and no dlseoants will "
allowed. Copy must be aeeompanllt! by "mlttane. In
full, and must reach the New York om .. by the ftrst .,
the month preceding the date of Iss.e.
"'II'-
THE AUDIO EXCHANGE has the largest
selection of new and fully guaranteed u sed
equipment. Catalog of used equipment on reo
quest. Audio Exchange, Dept. AE, 159-19 Hills ide Ave., J amaica 32, N. Y. AXtel 7-7 577;
367 Mamaroneck Ave., White P lains, N. Y. WH
8-3380; 836 F latbush Ave., Brooklyn, BUckminster 2·5300.
LOOKING FOR CLEAN RESPONSE T O 20
CYCLES? Listen to the rad ically new Racon
"Hi-C" 15" foam suspens ion speaker. Racon
E lectric Co., I nc., 1261 Broadway, New York
I, N . Y.
HIGH FIDELITY SPEAKER S REPAIRED
Amprite Speaker Service
70 Vesey St., New York 7, N. Y.
BA 7-2580
Long P laying records 20 to 50%
d isco unts; brand new, factory fresh; unplayed ; all labels. Send 20¢ for cata log to
Record Discount Clu b, 1108 Winbern, Houston
4, Texas.
(j-E lem ent BROAD-BAND FM A ' TENNAS.
All seam less alum inum. $10.95 ppd. Wholesale
Supply Co., Lunenbu rg 10, Mass.
DISGUSTED of "HI " HI-Fi Prices?
Unu sual savings on a ll yo ur h igh fidelity reo
qu irements. Write Now. Key E lect ron ics Co.,
120 Liberty St., New Yo rk 6, N. Y.
DISCOVER our "SIX UNIQUE SERVI CES"
and Rock Bottom Prices on Hi-Fi; Stereo.
Write the Silver Trumpet, 406.11. Walnut,
Alexandria, Indiana.
SALE - Western E lectric 555 drivers
(three ), excellent. $35.00 each. F.O.B. Los
Angeles. Arth ur D. F ish er, 855 South Du ns·
m ni r, Los Angeles 36, Calif.
SAVE! SAVE! on t he finest In Hi-Fi com·
ponents. All equipment br and new in factory
sealed cartons. Do·n't delay, write fo r f r ee list
today. Downey Hi·Fi, P.O. Box 2065, Downey,
Calif.
PORTABLE CUTTER-PLAYER. Almost
ew Rek·O·Kut " Cha llenger" ($500.00 List)
For Sale, reasonable otIer. AUDIO, Box 801.
15" TANNOY in 22 cu. ft. sand-loaded
infinite barne, beautifully fin ished walnut,
$195.00. J. Albert, 135-33 230 St., Queens,
N. Y. LA 5·8065.
Add "Pr esence" to H i·Fi, Radio w ith
KLI PPON Ceiling, Co rner, E nclosu re. Use in
OTHER Rooms, Patio too. Kli ppon $19.95
uses any 8" speaker, recommend R.A. avail·
able at $10.95. Just cli p·it·on. Nothing else
needed. Arth ur J. Crawfor d, 150 E. 79, New
York 21, N. Y. LE 5-5020.
FOR SALE: $300 cabinet; cutouts-tuner,
changer, turn table, etc. $65. Frank York, 11438 196 St., St. Albans, N. Y.
EMPLOYMENT
High F ideli ty, Sales, P urch asing, Correspondence; 8 years eXp;Jr ience ; desir e con tact
wit h representative, manufactu rer, or any al·
lied industry; no r etail. AUDIO, Box 802.
AUDIO
•
AUGUST, 1957
PROFESSIONAL
DIRE(;TORY
UNHAPPY WITH
"HI" HI-FI PRICES?
Write us your H i·Fi needs now
DEPT . AA
KEY ELECTRONICS CO.
N. Y. 6, N. Y.
Corcle 47B
PROFESSIONAL RECORDING SERVICE
T apes m ade, copied, masters cut, processed,
pressings made - short runs our specialtyall AMPEX 300's Telefunken & Altec,
HYDROFEED Lathes, monofusion presses.
Components Corporation, 106 M ain St. ,
Denv ille, N . J.
Phone: ROckaway 9-0290
Circle 47C
CANADA
High Fidelity Equipment
GLECTRO--UOICE
~<?Y~~T~!~!~~~ I
Circle 47E
SOUND
R
A
TI O
N
Circle 47F
HIGH-FIDELITY HOUSE
Most complete stock of Audio
compenenh in the West
Phone: RYtm 1-'171
536 S. Fair Oaks, Paaaden. 1, C.llf.
Circle 47G
.J
.'-~ ~Q
~ IIntennll s'lstems
HIlh ••1. 8roaO •• ' Y..I , . . .IX.....ltl'lty t. MtIo
72 •• , '00 .h .. 1.,lt. Dnl,... , .. frl ... FM.
APPARATUS DEVELOPMENT CO.
Dept. C
Wethersfield 9. COIIII.ctlcut
Circle 47H
AUDIO
•
AUGUST, 1957
REK-O-KUT
PURCHASES
AUDAK.
Two of the most respected names in the
a udio industry were j oined recently when
t h e Audak Company was purchased by
Rek-O-Kut Company, Inc. Accord ing to
George Silber, Rek-O-K u t president, production of a ll Audax units will be tra nsfen'ed to the n ew Rek-O-K u t plant wh ich
was opened in July. The trad e m a rk Audax,
ol dest in its fie ld, will b e continue d and
a n ew corporation to b e known as A udax,
In c., w ill be formed as a division of RekO-Kut. Mr. Silber will be president of the
Audax divi Sion, and Maximilian Wei l,
foun d er of the Audak Company, will act
as con s ultant an d c r eative engineer. Th e
A u dax division has developed a n ew cartridge of revolu tionary design which wifl
be marketed within the next few months.
AMPEX ACQUIRES ORRADIO INTEREST. A jOint statement issue d by
George I. Long, president of Ampex Corporation in Redwood City, Calif., and J.
Herbert Orr, president of ORRadiG Industl'i.es, Inc., Opelika, Ala., disc lose d that
Ampex has acq uired a 25-per ce nt interest
in the tape-making firm. Team effort by
engineering a nd research facilities of
Ampex and ORRadio will be directed
primarily toward the production of high est possible quality magnetic recording
tape for a udio, video, and computer use .
HEN the AR·l speaker system first made
its appearance on the hi fi market, our
published specifications were sometimes
greeted with skepticism; for a speaker to per·
form as claimed, particularly in such a small
enclosure, was contrary to audio tradition .
W
Now, two years later, the AR-J is widely ac·
cepted as a bass reference sta ndard in both
musica l and scientific circles. There is general
under stan di~g of the fact that, due to the pat·
ented acoustic suspension design, the small size
of the AR·l is accompanied by an advance in
bass performance rather than by a compromise
in quality.
as are Audio Fidelity records. The records,
Complete Lin:.~. Complete Service
Hi-Fi Records - Components
and Accessories
CORP O
NoW ...
AUDIO FIDELITY ANNOUNCES NEW
LATIN LINE. In an effort to bring to the
American market some of the best recorde d Latin-American m u sic, AudiG Fidelity, Inc., a nnounces negotiations h ave
been compl e ted with Musart of Mexico for
the production an d release of t h e Musart
label in the United States. Sidney Frey,
president of Audio Fideli ty, Inc., in in trodu ci ng the new 12-inc h album li ne,
stated that the discs a re recorde d in true
hi-fi a nd wi ll be manufact u red in thi s
co untry to th e same exacting standards
Circle 470
WJ
1~
protected by g lassine envelopes in s ide attractive 4- co lor jackets, are now be ing
r e leased through the firm's present roster
of independent d istributors .
G-E REORGANIZES HI-FI SETUP.
The General Electric Company has reorganized its high-fide lity sound compon e n ts operations. Responsi bility for e n g in eering, manufacturing, an d m arketing of
h i-fi products has been transferred from
the company's receiver departm ent in
Syracuse to its specialty e lectronic com ponents department in A uburn, N . Y. The
c urre nt G -E hi-fi line wil l b e expanded in
the near f uture, according to Edward L.
Hu lse, ge n e r a l manager of the d epartment.
PERMOFLUX RE-LOCATES. L. M.
Heineman, president of Perm.oll.ux Products Company, anno un ces that all of the
firm's eng in eeri ng, man u facturing and
sales offices are now concentrated in its
new 31,OOO- sq. -ft. p lant in Glendale, Cali f.
Permoflux
manufactures
high-fidelity
loudspeak ers, h eadphon es, transformers,
microphon es, receivers, induction picl{ u ps,
transistorized amp lifi ers, intercom sys tems a nd power s up plies. Manu facturers
a nd distributors are asked to direct their
i nquiries on Permoflux produ cts directly
t o the attention of the sales depa rtm ent
The AR·2 is the first applicatIOn of the acoustic
suspension principle to a low-cost speaker sy,s·
tem . Prices are $89 in unfini shed fir cabinet,
$96 in mahogany or birch, and $102 in . wal nut. .
We would like to suggest, as soberly as we invite comparison between the AR·l and any
existing ba ss reproducer, that you compare the
AR·2 with conventional speaker systems wh ich
are several times higher in price. No allowances
at all , of course, should be made for the AR-2's
small size, which is here an advantage rather
than a handicap from the point of view of
reproducing quality.
IF YOU ARE MOVINC
Please notify our Circulation Department
at least 5 weeks in advance. The Post
Office does not forward magazines sent
to wrong destinations unless you pay additional postage, and we can NOT dupli:cate copies sent to you once. To I.ve
yourself. us, and the Post Office a heildache, won't you please cooperate? When
notifying us, please give your old .ddress
and your new address.
Circulation Dep.rtment
Literature is available on request.
RADIO MACAZINES, INC.
P. O. Box 629, Mineol., N. Y.
ACOUSTIC
RESEARCH, INC.
24 Thorndike St•• Cambridge 41, Mass.
Circle 47A
47
SAVE % - PAY PART·BY·PART - HAVE FUN
Assembling the SCHOBER
ADVERTISING
ELECTRONIC
ORGAN in KIT form
IN 0 EX
•
A coustic Research, Inc . . ... ...•• , .... 47
All ied Radio Corporation ... . . . • •..... 48
Altec Lansing Corporation'
33
Apparatus Development Corpcration
47
Audak Company . ....•..
........... 34
29
Audio Fidelity Recordings
Audiogersh Corporation
6, 7
....
Bell Telephone Laborator ies . . ....... . 14
Bogen, David Company, Inc . .... .. Cov. II
Bradford & Company ... , ... . . . . ,., .. 42
British I ndustrie s Corporation . facing p. I, 3
Classified
. .. . " . , .. .. . ... .•.. .•.. .. 46
Collaro Record Changers .....•. .• , . .. 43
Components Corporation
Dy na Company
write for literature
EICO
... ar~nl:z
,«:e:unpany.
,
, ,
25-14 Broa'dwaY' ' Long Island City 6,
,'t
t
•
Electro-Sonic Laboratories,
1';1. Y.
. . .. ... 24
The SCHOBER ORGAN CORP.
Fisher Radio Ccrporat ion .. ...•.... . .. 35
2248-K Broadway, New York 24, N . Y.
'Designed by Richard H. Dorf
(Pioneer)
•.. . .. .•... 8, 9, 10, II
High Fide lity House.... .. .... .
47
Hollywood Electronics
47
.........
knight-kit
Key Electronics Co. " , . .. , ..... .. .. . . 47
Kierulff Sound Corporation . . .•... .. ,. 47
• Wllh Deluxe Custom Cabinet
•• Prihled
AFC &Flywheel Tuning Control
Circuit-Easy to Build
Lansing, James B., Sound, Inc. '"
Cov. III
your money can bu;V. Covers 88 to 108 mc;
features AFC; pre-adjusted RF coils, pre-aligned
IF's; cascode broadband RF amplifier; driftcompensated oscil1stor; lighted pointer. Sensitivity better than 10 niicrovolts for 20 db of
<juieting a.cross entire ban~ . Ideal .lor use with
Knight-Kit 20-Watt amplifier or any amplifier
with phono-tuner switch. Comple~asy to
build. Shpg. wt., 12 lbs.
Model Y.751.Net F.O.B. Chicago, only
•
Marantz Company • •..• .• . . . . . .. .... . 48
Minnesota Mining and Manufacturing
Company .. ... . . ..•. . •. •... •... . 4, 5
IIJD
Pickering & Company •.•...... •• .. .. 13
SUPPLEMENT
Pilot Radio Corporation . .•... ....•• .•
Send for ill Lists all the low.cosl
Knight-Kils, plus top values in
Hi·Fi, Recording, P.A., Amateur
and Electronic equipment.
FREE - WRITE TODAY I
ALLIED
RADIO
:
ALLIED RAQIO, Depl. ~17 -H7
100 N. Weslern Ave., Chicago 80, III.
I
0 Send Tuner Kit No. Y-751. $ _ _ __
Professional
Robins
••
enclosed
I Address
Circle 48B
4S
Directory
Rigo Enter pr ises
••
•••
•
•
.I•
.........................
: 0 Send FREE Supplement No. 165
I
• . Name
Gancer can't strike me,
I'm hiding,
North American Philips Company . . . . . 32
$37 75
•
48C
30
• True Hi·FI Response for Less
The best-looking, best-performing tuner kit
•
Free Literature
Complete descriptive booklet and price li st are
available on request. And , if you wish to hear the
glorious pipe organ tone of th e Schober Electronic
Organ, a 10" long-playing demon st ration recording is
available for $2. This is refundabl e when you order .
Write today and see what a fine instrument you can
get at such a great saving.
Ercona Corporatior.l ...... . ...... . ... . 46
Leonard Radio, Inc. . ..•. " . . . .. .. . .. 40
I
Compact CONSOLE
One of the many exclusive fe atures of this exceptional organ is the hand some console, in a wide
variety of finishes. It is equally at home in a traditional or modern setting, and takes l ittle more space
than a spinet piano.
JansZen Speakers I Neshaminy Electronic
Corp. ) .... ....... , .. , .. ,. .... .. . 27
®
HI-FI FM rUNER KIT
.
41
.. .... . . . 47
Elgin National Watch Company
'
-a UIED'S'
Y.751
Inc .
Electro-Vo ice Sound Systems
Heath Ccmpany
$37 75
. . ,.... . . ... . .. .... .. 39
......... .. ....... Cov. IV
Fukuin Electric
," OWN
SENSATIONAL
.... • ..... , . . 47
Now you can afford a real, full concert organ, 'just
like those made by the foremost organ manufac.
turers. Because over '/2 the cost is saved whe n you
assemble it yourself. And it's REALLY EASY: only
24 separate units , all with printed circuits, and
detailed·to-the-smallest·st ep instructions. In add,·
tion , you purchase each of the 24 ki ts when you are
ready for it - and can afford it.
You'll get a real kick out of putting the Schober
El ectronic Organ' togethe r - and then sitting down
and pulling the stops for Strings, Trumpets, Clar.
inets, Diapasons, Flutes, etc. El ectronic Percussion
optional; chimes available.
:
25
.................... 37
I ndustries Corporation
Sargent-Rayment Co.
Gance?'?
....•.. , .• .. ... 47
46
. ............ ... 36
Schober Organ Corporation .. .. .. ..... 48
Sherwood Electronic Laboratory, Inc. ' "
Shure Brothers, Inc. . .. . .. .. ..... •... 31
Triad Transfo rmers Corp.
2
University · Loudspeakers, Inc. . . . . .. .. . 23
The American Cancer
Society says that too
many people die of it,
NEEDLESSLY! That's why
I have an annual medical
checkup however well I
feel. I know the seven
danger signals. And
when I want sound
information, 1 get it
[1'om rny Unit of the
AMERICAN CANCER SOCIETY
AUDIO
•
AUGUST, 1957
(
NfWI12-WAn Williamson"JYpe HIGH
FIDELITY INTEGRATED AMPLIFiER HF12
l~~"':""""'~';;"-"""
0-.._----:
with Preamplifier,
Equalizer &
Control Sedlon
95
KIT$34'5 WIRED $57
\I
Compact, beautifully packaged 8< styled. Provides
complete "front·end" facilities and true high
fidelity performance. Direct tape head 8< mag.
netic phono inputs with NAR.TB (tape) 8< R.IAA
(p,hono) feedback equalizations. 6·tube tircuit,
dual triode for variable turnover bass 8< treble
feedback· type tone controls. Oalpul Power. 12
w cont., 25 w pk. 1M Dill. (608< 6000 cps @ 4:1):
1.5% @ 12 w; 0.55% @ 6 w; 0.3% @ 4 ·w.
Freq. Reap •• 1 w: ±0.5 db 12 cps - 50 kc; 12 w:
±0.5 db 25 cps - 20 ke. Harmonie Disu 20 .,p..
2% @ 4.2 w; 1-2% @ 2.5 w; 30 ep5l 2% @ II w;
1-2% @ 6.lI w; 40 "PSI 1% @ 12 w; 1-2% @ 9.lI w:
2000 epu 1-2% @ 12 w; 10 kc. 1% @ 10 w; M!%
@ 6 w. Transient Reap. excellent square wave
reproduction (4 usee rise·time); negligible ring.
ing, rapid settling on 10 kc sq uare wave. Inverse
Feedback. 20 db. SlabllllT Matsln. 12 db. Damp_
JnS Factor. above 8, 20 cps - 15 ke. Speaker
Connections. 4, 8, 16 ohms. Tone Control Ranse.
@ 10 ke, ±13 db: @ 50 cps, ±16 db. Tube ..
2·ECC831l2AX7, I·ECC82/12AU7, 2·EL84.
l·EZSI. Size: HWD: 3%" x 12" x S\4". 13 Ibs.
#HF61A KIT
NEWI 50-WATT
Ultra-Linear
Ultra-Linear
HIGHFIDELITY
INTEGRATED POWER AMPLIFIER HF52
HIGH
FIDELITY
POWER
AMPLIFIER
HF50
KIT $5795
with Prllamplifier, Equalizer & Control
Section
KIT $6995 WIRED $10995
Like the HF60 shown below, the HF50 features
virtually absolute stabiHty, flawless transient
response under either resistive or reactive (speaker)
load, Be no bounee or flutter under pulsed condi.
tions. Extremely high quaUI)' outpu t transformer
with extensively interleaved win:lings, 4, S, & 16
ohm speaker connections, grain-oriented steel, &
fully potted in seamless steel case. Otherwise identical to HF60. Output Po~er: 50 w cont., 100 w pk.
1M Diolortion (60 Be 6000 cps @ ,4: I): below 1%
at 50 w; 0.5% @ 45 w. Harmonie Dlst •• below
0.5 % between 20 cps Be 20 kc within I db of rated
powe r. Freq. Resl" at 1 w: ± O.S db 6 cps -60
kc ; ± O.I db 15 cps : - 30 kc at any level from , !
mw to ra ted powe r; no peaking or raggedness
outside a udio ra nge. All other s pees identical to
HF60 below. M a tching cover ~Iodel E.2, 54.50.
Ultra-linear
HIGH FII.lElITY POWER AMPLI FIER #HF60
with ACRO TO-330 OUTPUT TRANSFORMER
52495 • WIRED 537 95
With PDwer Supply: #HF61 KIT
NEW;
50-WATT
$2995 , WIRED '4495 KIT $7295
WIRED $9995
Superlative performance, obtained through finest
components Be circuitry. EFS6 low-noise .voltage
amplifier direct-coupled to 6SN7GTB cathode
coupled phase inverter driving a pair of UltraLinear connected push-pull EL34 output tubes
operated with fixed bias. Rated power output:
60 w (130 w peak). I~I Dls.ortlon (GO 8< 6000
cps at 4: I): less than I % at 60 w ; le ss tban
0.5% at 50 w. Harmonic J)istortlon: less than
0.5 % at any freq. between 20 cps & 20 kc within
I db of 60 W. Sinusoidal FrC<l. Resp. : at I w:
35 kc at any level from ) mw to rated power; no
peaking or raggedness outside audio range. Square
Wave Resp.: exce llent from 20 cps to 25 kc, 3 usee
rlse·time. Sensitivity: 0.55 v for 60 w. Damping
eentrle level control. 4 hi-level 8witclted inputs l~ Faetor: 17. Inverse Feedback: 21 db. Stability
(tuner, tv, tape, aux.) &: 3 row.level Inputs ~sepa. ; Margin: 16 db. Hum: 90 db< below rated output.
rate fronl panel low.l,,~el Input selector permits i · ACRO TO.S30 Output T.ansformer (fully potted).
concurrent use of changer 8< turntable). Proper i Speaker Taps: 4, 8, 16 ohms. CZ34 extra .. ruggcd
plek-up loadJ"f! & etenaatlon provided for all ,! rectifier (indirectly-heated cathode eliminates high
quality cartridges. Ham bal. control. DC super· ' starting voltage on electrolytics & delays B + until
amplifier .tubes warm' up) . Inpu. level eontrol.
imposed on filament supply. 4 convenience out·
lets. Extremely flat wldeband freq. resp.• ±I db
Panel mount fuse holder. Both bi.s and DC balance adjustments. Std octa l socket p rovided for
8·100,000 cps; ±0.3 db 12-50,000 cps. Extremely
pre-amplifier power .take-off. Size: 7" x 14" x 8" .
• oensilive. NegllslJ>le hum, noise. harmonic or 1M
30 Ibs. Matching cover Model E.2 54.50.
distortion. Size: 4·7/S" x 12·5/16" x 4-7/8". 8 Ibs.
Will not add distortion or detract from the wide·
band or transient response of the finest power
amplifiers at any control settings. Hil\'h. quality
feedback circuitry throughout plus the most com·
plete conrrol & switching facilities. Heavy-gauge
solid brushed brass panel, concentric controls,
one-piece · brown enamel steel cabinet for lastingattractive appearance. Feedback.type, sharp cutoff (12 db/octave) scratch & rumble filters. Lowdistortion feedback equalization: 5 lllost common
recording cunes for LPs & 78s including RIAA.
Low-dlstortioD feedback tone controls: provide
large boost or cut in bass or treble with mid-freqs
&: volume unaffecled. Cenlralab printcd-eircuit l.'
Seniol! "Compentrol" Joudneee control with con-
See the "BEST BUYS" NOW IN
SrOCK at your nearest distributor.
Write for free Catalog A-8
Prices 5% higher on We.. roa.t.
Genuine 2· way book·shelf size speaker system. J en sen
heavy duty 8" woofer (6.8 oz. magnet) &: malchil)g:.l1ellsen
compres$ion ~ drivcr expone ntial horn tweeter wirh level
control. Smooth clean bass &: crisp extended highs free of
colora tion or artificial brilliance. Factory.built tuned ba~s
reflex birch ha rdwood m binct (not a kit ) constru cted to
high quality standards. Neutral' acoustical g rille cloth
fram ed by a smooth-sanded solid birch molding. Freq.
Res p. measured 2 ft. awa y on princi p iil ax is in a nechoic
chamber with I walt input - Woofer: ± 4 db SQ-I SOO cp s;
T".eter: ±2 db 2800-)0.000 cps; Crossover Region: 18002S00 cps, shift in level over this region depends on tweeter
level control setting. Power· handling capa" i.ty: 25 wa tts.
Sj~e: 23"xl1"x9". 25 lbs. Wiring Time: 1S min.
Combines a power amplifier section cssentially
Identical to the HF50 I'ower ampll!ler witb a
preamp-equalizer control se ction similar to HF20
below. Provision for use with electronic crossover
network &: additional amplifier(s). See HF50 for
response & distortion specs; HF60 for square wave
response, risc·time. inverse feedback, stability
margin, damping factor, speaker connections;
HF20 for preamplifier, equalizer & control section
description. Hum ' &: noise 60 db below rated out·
put on magnetic phono input (S . mv input for
rated output), 8< 75 db below rated 'output on
high level inputs (0.6 v input for rated output).
Matching cover ~Jo(lcl E·l, 54.50.
COMPlETE with Preamplifier, Equalizer
& Control Section
20-WATT Ultra-Linear Williamson-Type
HIGH FIDELITY AMPLIFIER #HF-20
WIRED '7995
KIT $4995
A low-cost, complete-facility amplifier of tbe
highest quality that sets a new standard of performance at the price, kit or wired. Rated Power
Outpu': 20 w (34 w peak) . 1M Distortion (60 &
6000 cps/4:1) at rated power: ] .3% . Max. Har ..
monic Distortion between 20 & 20,000 cps at 1
db under rate d power: ap,prox. 10/0. l\fid.hand
Harmonie Distortion at rated power: 0.3 % . Power
Response (20 w) : ±0.5 db 20-20,000 cps; ± 1.5 db
10-40.000 cps. Freq. Resp. ( !/.i w ) : ±0.5 db 1335 ,000 cps; ±1.5 db 7- 50.000 cps. 5 fe edbaek
c(lualizations for LPs &: 78s. Low·distortion feedback lone controls: large boosts or cuts in bass or
treble with mid-freqs . & volume unaffected . Loudness control & separate .Ievel set control on front
panel. Low Z output to tape recorder. 4 hi-l evel.
switched inputs: tuner, tv, tape, au x ;· 2 tow-level
inputs for proper loading with all cartridges. Hum
bal. con.rol. DC superimposed on filament supply.
Extremely fine output transformer: interleaved
windings, tight coupling. care ful b ahmcing, grain.
oriented steel. SY1!" x 15" x 10". 24 Ibs.
Matc hin g co ve r Mod e l £·1 , 84.50
, _:~:::_:l~~~~_::-: ;. ; . :-' ,
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1l1itjg
·'JBL" meaft8 ..JAMES
B . LANSING SOUND ~ INC. ,
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