Audio July 1958
/
/
J •
II
I
I
I
Even 18-year-old Bogen systems
ADAPT EASILY WITH NEW
SINGLE-KNOB VOLUME CONTROL
-Y:OU CAN
CONVERT
TO STEREO
THE RIGHT WAY
.. . RIGHT NOW!
There's stereo in your future if you own a Bogen
system (or plan to buy one). In fact, stereo conversion can be made right now on any Bogen
high-fidelity system made since 1940! Not just
an added second channel, but completely integrated, balanced-sound stereo. You pre-set tone
and volume controls only once, from then on
regulate volume of both channels simultaneously
from a single volume control. That's the right
way to convert to stereo. Here's how:
JCTtl L
-------'
rST
ER EO TAPE '
r- -
, A:<D / OR DI SC
I
l::"':~,!!_-_"J
r-----'
I
KEW
T U :< E R
II
STA'
r- l\ E W
1)
II
-"
11
,...--<,
,
f.l...--j A"PLlFl F:R
1..- - - - - - .(1
~-- - - ---l :
'- - - - - - - ))
.n
/': :
, I
'.u
_- -----, 1
I S TERE O TAPE
1
OR DI SC
P.--f
'H
\.- - - - - - --t ,
~ . - -- ----~
STI O·A
-f1
rt---<,./ 1',1
l',
~..:.=:::::_-_~
'.u
SPEAKER
' - --- - ---~ S P E: AK E R
A You can convert to single volume control and easily balance your
• system with th e Bogen STAl Stereo Adapter if you own any of
these Bogen or Challenger high-fidelity amplifiers: AClO', DBlO,
DB114, DB125, DB130, PR100, PR100A, PX10, PX15. Simply add the
STA1, your choice of speaker and a DB130, DB125, DB114 or AC10· .
B
If you own either the Bogen RB115' or the Bogen RB140, you
• can convert with the Bogen STAl Stereo Adapter and the neces sa ry second-channel components, includin g a DB130, DB125, DB1l4 ,
or AClO' amplifier.
C
If you own any Bogen or Challenger high-fidelity amplifier manu• factured since 1940 or a Boge n high-fidelity receiver, you can
convert with the Boge n ST10-A Stereo Adapter-Amplifier and a
seco nd speaker system.
EASY AM-FM STEREO CONVERSION: To receive stereo broadcasts from simultaneous AM-FM transmission with your present
tuner , add the f ollowin g Bogen tuners: with any AM tuner, th.e new
Bogen FM51; with any FM tuner, the new Bogen AM91. With a n y
Bogen AM-FII1 tuner or receive r, add either the AM9l or F?lI5].
·Series B or late r
"'Slightly
~lgher
1n the \Yes t
You?' Bogen dealej' is ?'eady now
with complete information on how
to convej·t YOU?' system to
stej·eo. S ee him today!
.. . because it sounds bette?'
David Bogen Co., P.O. Box 500. Pal'amus. New Jersey · A Divi s ion of The Siegler Corporat ion
Manufactu1'e1's of High-Fidelity Components, Public Address Equipment and Intercommunication Systems.
JULY, 1958
VOL. 42 No.7
Successor to RADIO, Est. 1917.
fo r Ultimate Fidelity
*
ENCINEERINC
MUSIC SOUND REPRODUCTION
C. G. McProud, Editor and Publisher
Henry A. Schober, Business Manager
I-Iarrie K. Richardson, Associate Editor
Linda Sueskind, Assistant Editor
* outstand l ng honors bestowed, u nso li cit ed, by most
reco gn ized testi ng
organizati on s.
Janet M. Durgin, Production Manager
Edgar E. Newman, Circulation Director
Sanford L. Cahn, Advcrtising D ircctor
Special RepresentativeH. Thorpe Covington,
814 Lincoln St., Evanston, Ill.,
DAvis 8-8874
Mid West RepresentativeSanford R . Cowan, 300 W. 43rd St.,
New York 36, N. Y.
West Coast RepresentativeJames C. Galloway
6535 Wilshire Boulevard, Los Angeles 48, Calif.
-MEMIEI'
""It"" "
CONTENTS
Audioclinic- J oseph Giovan elli
Letters ........................................................ .
Audio ETC- Edwal'd Tatnall Canby
Editor's Review ..... .
Improving the Tape Amplifier- Hm'man Bt£I'stein and H em'V C. Pollak.
Transistor Beta Tester W ith Linear Scale-8M'gio BM'nst ein ....
An Amplifier Using New 6CZ5's- Nathan Gl'ossman
Hearing, the Determining Factor for High-F idelity Transmission- Part I
- Hal'vey Fletchel' '
Equipment Review-Tandb el'g Model 3 8tel'eo T ape Rec01"de?'-Lekt?'ostat
R ecOI'd Cleaner-Heathkit EA -2-12-watt Amplifie?'
Record Revue-EdwaHl Tatnall Canby
Jazz and All That- Cha?'les A . Robe?·tson .
..
.. ................
New Products
About Music-Harold Lawl'ence
Coming Events
New Literature
Industry Notes & People
Employment.
Advertising Index
2
6
12
14
17
21
23
24
28
36
40
46
50
53
55
55
56
AUDIO (title registered U. S. Pat. OIT.) Is published monthly by Radio Magazines, Inc. , Henry A. Schober, Prealdent ;
C. 0, lIcProud, Secretary. Executlv. and Editorial Omce., 204 Front St., Mineola, N, Y. Subscription rates- U. S.
Possenions, Canada and Mexico, $4.00 for one year, $7 .00 t or two years, an other countries, $5.00 per y.ar. Singl.
eopies 50¢. Printed In U. S,A. at Lancaster, Pa. All rights reserved. Entire contents copyrighted 1958 by Radio Magazines,
I ne. Entered as Second Class Matter February 9, 1950 at Ibe Post Omce, Lancaster, Pa. under the Act of March 3, 1879.
Postmaster: Send Form 3579 to AUDIO, P. O. Box 629, Mineola, N.Y.
AUDIO
•
JULY, 1958
First to achi eve under on e microvol t
sensitivity for 20 db FM quieting in creases station range to over 100 miles.
Other im portant features include the
new " Feath er- Ra y" tuning eye, auto·
matic frequency control , fl ywheel tun·
ing output level control and ca thode·
follower output.
Model S-2000 FM-AM Tuner 1139.5 0 net
Model S-3000 FM (on ly) Tuner S99.5 0 net
Forcomol ete specif icat i ons. write D ept . A-7
54
COVER PHOTO: One of the country's most treasured recording activities is that
performed by Recording for the Blind, Inc., a non-profit organization which
records text books, free of charge, for any blind p erson seeking an education.
H ere is shown a section of the group's recording center. New embossing techniques
and equipment, developed by CBS Laboratories, permit doubling the text content
of each disc by conversion to 16%-rpm operation.
RADIO MAGAZINES, INC., P . O. Box 629, MINEOLA, N. Y.
No matter what your source of music
-FM , your own discs, or tape-you
will enjoy it at its best comi ng fro m
Sherwood's complete homemusiccenter
... most honored of th em all! Sherwood
tun ers for exa mple .. .
ELECTRONIC L A BOR A TORIE S. INC.
4300 Norl h Cal ifornia Avenue, Chicago. Illi nois
T he "comp l ete h i gh fidelity home music ce nter. "
In New Yo rk hear " A cce nt on So un d" with Ski p
Wesh ner, W B A I-FM, week ni ghts, 9 P. M. In
Los Angeles. K RH M-F M , 10 P. M.
AUDIOCLINIC??
JOSEPH GIOVANELLI '"
Crossover Networks
ONLY FULLY
STEREOPHONIC
RECORDING AND
PLAYBACK SYSTEM ...
AT AN AMAZING
LOW PRICE!
Now, you can actually
record-as well as
playback-stereophonic
sound. The new
STERECORDER
captures all the realism
of the. original performance
.. . then reproduces this
exciting " living sound"
with full dimensional
depth and direction.
STERECORDER goes
beyond high fidelity and
"half-way" stereo units
with only monaural
recording. H ear a
demonstration today!
From th e fam ous name in m otion pictures:
Superscope Inc., Audio Electronics Division,
780 Gower St., Hollywood, Calif.
Q. I have seen very little p~tbUshed infol"
I)l.at'ion concel'ning CTossove?" neiwodcs.
Wou ld you s~tpply infonnation so that 1
can tackle constmction of them? What is
the I'eason fa I' the ~tse of such netwo?"7cs?
Ray E. Roehl'ic7c, East Chicago, Indiana.
A. Reseal'ch has not yet disclosed the
perfect speaker. A good speaker should be
capable of r eproducing the entire a ndio
frequ cncy spectrum flat from 20 to 20,000
cps. Distortion other th an frequency dis·
crimination should be under 2 per cent
t hrOJlghout the range. It has been fo und
that if a speaker reproduces the lows well,
it cannot vibrate rapidly enough to repro·
(luce the highs with sufficient magnitude.
If the size of the speaker is reduced iu
order to enable it to vibrate at sufficient
velocity and amplitude to reproduce t he
highs freq uencies, the uuit will lack low·
frequ ency output because the speaker can·
Hot couple to euough air to produce good
low-frequeucy r adiation. An 8- or 10-inch
model is nsually the best compromise.
Most of us dislike compromise and so
we have found it advisable to use more
than one speaker. Each speaker specializes
in rep rod ucing a specific portion of the
spectrum. The obvious procedure is to COll'
nect all the speakers across the amplifier's
output, and each will automatically r epro·
duce its part of the spectrum. Division is
automatic, since the speakers cannot repro·
duce each other's f requencies adequately.
This methocl of connection is a poor one
for at least three r easons, however:
(1) It is difficult to get good high·fre·
quency response from even a small speaker
unless all moving parts are extremely light.
Therefore, many such units (tweeters) ar e
structura lly weak. If frequencies below
those for which the unit was designed are
allowed to enter it, t heir amplitude would
be too great , the elastic limit of the mecha·
nism would be exceeded, and of course, it
would be destroyed. Even if the undesired
frequenci es did not ruin the mechanism, the
output at these frequencies would be dis·
torted because of t he non-linear mode of
vibration which t he cone produces when
confronted with freq uencies which are be·
yond its capabilities.
(2 ) The low-frequency radiator (woofer)
may have reson ances in its upper register
which are unpleasant. Ther efore , it is best
to restrict the Tange of this speaker so
that th e speaker will not be excited by
energy at its r esonant point.
(3) Each speaker placed across the line
lowers th e impedance presented to the am·
plifier. "Vhen each speaker is assigned a
definite portion of the spectrum, this effect
is minimized.
It is obvious now th at we must divide
the spectr um for use with speci alized
speakers. This division is accomplished
through the use of circuits known as cross·
over networks, or frequency dividing net·
works. The discussion and circnits following
illustrate the manner by which t hese net·
works accomplish their purpose. Notice that
there is no sharp cutoff or transition at the
point where one speaker takes over from the
other, High-Q, sharp-cutoff filters would introduce ringing at each transition point, or
* 3420 Ne1v7cil'k Ave., Broo7clyn 3, N .Y.
2
crossover point as it is mostly cOUllllonly
termed. 12 db/ octave is usually the ma.umum gradient of attenuation above or below the crossover point, as the case may be.
Some engineers advocate a more gradual
slope. I personally favor slope bet ween 3 and
6 db/ octave. It must be r emembered, however, that, with this gradual rolloff frequencies outside the range normally intended
will be present in the various speakers comprising the system, and the speakers must
be designed to handle more of these undesired frequencies than if they were used
with a network having a higher degree of
attenua tion.
It sometimes happens that t he woofer
used with a particular speaker system is
quite uniform in response up to, perhaps,
5000 cps, aftel' which the highs roll off
smoothly. There i s, in this case, no need
to limit the range the woofer is to handle.
Obviously a tweeter must be used to r estore
the highs. It must not, however, operate to
any great extent nntil 5000 cps is reached,
after which point its output rises as that
of the woofer falls. Figul'e 1 shows a ' circuit which COUld . serve tllis purpose. C, is
AMPL
TWEETER
- 3 db/oct.
WOOFER
Fig. 1
chosen to have a r eactance equal to that of
the tweeter at 5000 cps. Below this frequency the capacitor has a r eactance which
is greater than that of the tweeter so more
of the voltage is lost across the capacitor
than is developed across the tweeter. As the
£requency decr eases, less and less power i s
available to the tweeter, since the r eactance
of the capacitor becomes larger and larger
in comparison with that of the tweeter. As
the frequency decreases, the tweeter is
gradually isolated from the line. It therefore does not load the circuit wh en not
in use.
Suppose the composition of the tweeter
were such that, with the a ttenu ation of -
AM PL
TWEETER
-6db/oct .
Fig . 2
AUDIO
•
JULY, 1958
THE
PAGE
Serving the owners of Garrardworld's finest record playing ~ui,pment .••
and other discriminating bsteners
interested in high fidelity.
Standard
Ga rrard Tone Arm
with Stereo Cartr idge
(underside view
through a
transl ucent record )
New Comparator Guide-FREE
Garrard Sales Corporation. Dept. GG-18.
Port Washington, ~ew York.
Please send your new comparator
guide which compares all Ganard
players and their advanced features.
301
TPA/IO
Madl' TJII
Super
Chanler
Chlnler
Tranacrlpl!on
Turntable
Tranacr\pl!OD
ManuII
Player
,87.50
ToneArm
S54.50
,11.00
S24.50
$32.50
Deluxe
Name . .. . .............. . .. . ... .
Address .... . ...•.....•...... • •••
City
GARRARD SALES CORPORATION, PORT WASHINGTON, N. Y.
..... . . . .. . .......... . ... ..
Zone . ....... State . .... . .. ...... .
~
_____________
Fig~.~3_____________
AMPL
For over thirty years Bakers have
been making quality speakers for
the discriminating British audiophile. These speakers are so outstandingly superior that they have
long been known as "the best of
the British speakers."
Mister,
you're
lucky.
for the new
Bakers Ultra
12, full-frequency I'Bnge,
12" spealcer is
now available
in America for
the first time.
A loudspeaker cannot be any better than
what is put into it. The Bakers Ultra 12 1s
the bcst, not bccause of claims, but because
design, pa.rts, materials, ond care in construction mali:e it 80. So look at the "specs!' Freq uency range ... 20 to 25,000 cycles, 20 cycle
cone resonance. Flux density . .. 18,000 gauss;
190,000 maxwells. High compliant, plastic
foam, cone suspension. Non-resonant, cast,
open, aluminum frame. Light, sensitive aluminum voice coil and former. Fully tropicalIzed. Hand assembled. Extra powerful Alcomax III encased in red cellulose. Dust, rust,
and damp proofed. Exponential, balteJized
apex, cone. Power ... 20 watts plus. Voice
coil impedance . .. 15 ohms. A full spread of
20 to 25,000 cycles without distortional crossOl'er networks. Ingenious design and the use
of new materials, processes, and techniques
now JDD·k e crossovers unnecessary. Acoustic,
impedance and efficiency mismatch; "disembodied highs;" and other undesirable characteristics of croS80'VCI'S, nre thus eliminated.
fered by this simple network, the low fre quencies were great enough to cause tweeter
damage. Th e circuit shown in Fig. 2 can
be used to cause a more rapid att enuation
of the lows. This circuit is similar to that
of Fig. 1, but has a shunted inductance.
C. functions as before, but its value should
be decreased to 0.707 times the value as
calculated above.
L . is designed to 4ave a l'eactance at
the crossover frequency which is equal to
1.414 times the reactance of the tweeter at
AMPL
TWEETER
WOOFER
Fig . 4
the crossover point. As the frequency decreases, the reactance of L f increases. This
results in the total reactance to the capaci·
tor being less than it would without the
inductance across the tweeter, with the reo
sult that the voltage division b etween ca·
pacitor and tweeter is greater than the
attenuation offer ed by the circuit of Fig. 1.
Suppose now that we have found it neces·
sary to attenuate the high-frequency signals feeding the woofer. We still wish to
attenuate the lows fed to the tweeter a before. The circuit of Fig. 3 could be used .
Notice the similarity between Figs. 1 and
3. (Consider the tweeter hookup in Fig. 1,
and the woofer hookup shown in Fig. 3.)
In Fig. 3, L, is in series with the woofer,
whereas in Fig. 1 C, is in series with the
tweeter. L , is designed to equal the reo
actauce of th e woofer at the crossover fre·
quency. As the frequency rises above this
point, the reactance rises high er than that
of the woofer, a nd again a voltage divider
is formed. Less and less signal is available
to the woofer as the frequency increases_
As the tweeter takes over, the woofer is
gradnally removed from the circuit, "un·
loading" the line except for the tweeter. In
all of the preceding circuits, the impeda nce across the line varies somewhat.
A circuit known as a constant-impedance network is shown in Fig. 4. This circuit attenuates the response of the woofer
still further . Notice that the circuit for th e·
woofer branch of the network is similar
to that of the tweeter branch. Of course,
the roles of the capacitors and inductances
a re r eversed, since they behave oppositely
with r egard to frequency a ttenuation. This.
circuit is th e standard pa rallel configura·
tion of a co nstant·impedance two-way
crossove r network, and the impedance presented to the amplifi er is essentially con·
stant throughout the entire audio r ange_
Va lues a r e as follows: L , = 1.414 x Ro/2!{t
and Cf = .707/2!{t Ro where Ro is the impedance of the speakers (and .the output transformer tap) a nd t is the crossover fre·
quency. Note that both inductances a re of
the same value and both capacitor s a re thesame.
In many instances, it is d esirable to add
a third speal\Cr to the system. 'fhe fr equency range covered by the woofer is reduced to perhaps 250 cps. Th e third spe-akercovers the gap from 250 to 5000 cps, and
is therefore known as the midrange speaker ..
Figuj'e 5 shows the complete circuitry for
a. crossover network which can be used with
a three-way speaker system. L , and C, are
connect ed as in Fig. 4, and supply signal
to the woofer. Also across th e line from
the a mplifier are C, and L ,. Signals for th e
two remaining speal,ers are taken across
L ,. C, is designed to attenuate all signals.
below 250 cps, as is L ,. From L , we use'
another crossover circuit similar to that of
Fig. 4. The l'emainc1el' of Fig. 5 is, there·
fore, a two ·way network. The midrange
speaker can be considered to be the woofer,.
and the tweeter to be itself. Since attenua·
tion below 250 cps ha.s already been accom·
plished by L , and C" it is necessa.ry ouly'
to attenuate frequencies above 5000 cps
from appearing in the midrange speaker,.
(Continued on page 45)
which cannot
be foulld in allY other speaker, makJls the
Bakers IDtra 12, unquestiollably, the finest
This combination of features,
TWEETER
reproducer today. And the price . . . a mere
$85.00 . . . for the best.
It you want a speaker that is fa·r superior to
anything now availablc, insist on a dealer
demonstration. You wi\) be amazed at its
smoothness, definition, cleanness, naturalness
. . . n certain "something" that you have
never heard before. Lucli:y owners say,
"~lister, this is it." The "specs" teU you
why.
MIDRANGE
AMPLIFIER
Write for Iite..atUl·e • • •
anci become sound happy.
WOOFER
BRADFORD AUDIO CORP.
Sole distributors for the United States
27 East 38th Street
New York City 16, N. Y.
OX 7-0523
4
Fig. 5
AUDIO
•
JULY, 1958:
·,
stereo
tape deck kit
M~5~~H,.~~D
stereo equiplDent
cabinet kit
$149 95
95
SPEAKER WING MODEL SC-1L or R $39
ea.
$143 95
CENTER SECTION MODEL SE-l
Enjoy t he wonder of Ste reophonic sound in
you r own home ! Precision eng inee red for fine pe r·
formance , t hi s ta pe deck provides mo nau ral·record /p lay·
back and ste reo playback. Tape mec han ism is supp lied complete. You bu il d on ly t he
preamp lifier. Featu res include two printed circuit board s- low noise EF·86 tubes in
input stages- mic and hi· leve l inputs- pu sh·pu ll bias·erase osci llator for lowest noise
level-two cathode foll ower outputs , one for each ste reo channel-output switc h for
instantaneous monitoring from tape while recordin g. VU meter an d pau se control for
ed iting. Tape speeds 3Y. and 7Y7 IPS. Frequency response ±2 db 40·12,000 CPS at 7Y,
IPS. Wow and f lutter less t han .3%. Signa l·to·noise 55 db at less than 1% tota l harm on i c
distorti on. NA RT B playbac k equa li zation. Make you r own high qua lity recording s f or
many pleasant listen ing hours.
.
Beautifu ll y designed, t his ste reo equipment cabinet has'
amp le room provided for an A M·FM tu ner-tape deck
- prea mpl ifier - amplifiers - record change r - rec·
ord storage and speake rs. Constructed of Y." soli d·
core Phili ppine mahogany or select bi rch plywood,
beautifu ll y grained . Top has shaped edge and sli ding
top pane l. Sli ding doors for front access . Mounting
panels are supp lied cut to fit Heathkit un its with extra
blank pane ls for mou nting· your own equ ipment. Easy·
t o·asse mbl e, all parts are precut an d predrilled. In·
clu des all hardware, g lue, legs, etc. and detail ed in·.
struction manua l. Speaker wings and center un it can
be purc hased separately if desired. Ove rall dimensions
with wings 82" W. x 37" H. x 20" D. Send for free details .
.
,,'.'. /
,
-;
!
I
DELUXE AM-FM
TUNER KIT
HEATHKIT
MODEL PT-1
$89 95
Here is a deluxe combination
AM· FM tuner wit h al l the ad·
va nced design featu res requ ired
by t he cri tica l list ene r. Ideal for
stereo ap pl ications since A M
and FM ci rcuits are sepa rate and
ind ividually tuned. The 16·tube
t uner uses th ree circuit boards
for easy asse mbly. Prewired and
prealigned FM front end. A FC
w ith on /oft sw itch - flyw hee l
tun in g and tun ing mete r.
STEREO PREAMPLIFIER KIT
HEA THKIT
MODEL SP-2
$56 95
T his un ique two·channel con·
trol center provides all controls
necessa ry in stereo app li cations.
Bu il ding block design lets yo u
buy basic sin gle channel now
and add secon d snap· in channe l
late r for ste reo without rewiring.
12 inputs each with leve l con·
t rol - NAR TB tape equa lization
- 6 dual concentric controls in·
c l uding loudness cont rol sbui lt·in powe r su pply.
55 WATT HI-FI
AMPLIFI ER KIT
HEATHKIT
MODEL W -7M
$54 95
Fi rst ti me eve r offered - a 55,
watt basic hi ·fi amp lifier for $1
per watt. Features EL·34 push·
pu ll output tubes. Fre quency reo
sponse 20 CPS to 20 KC w ith
less than 2% harmonic disto r·
tion at fu ll output throug hout t hi s
range. Input leve l control and
" on ·off" switc h provided on
·front panel. Unity or maxim um
dampi ng facto rs fo r all 4, 8 or 16
ohm speakers.
12 WATT HI-FI
AMPLIFIER KIT
HEATHKIT
MODEL UA-1
$21 95
Ideal for stereo applications, this
12·watt power package repre·
sents an outstand i ng do ll a r
va lu e. Uses 6BQ5 / EL84 push·
pu ll out put tubes. Less t han 2%
tota l ha r mon i c distort i o n
th roughout the entire audio
range (20 to 20,000 CPS) at fu ll
12·watt output. Designed for use
with preamp lifier models WA·
P2. or SP·1 . Taps for 4,8 and 16
oh m speake rs.
For cOIl1plete inforIl1ation on above kits-Send for FREE FLYER.
HEATH COMPANY •
AUDIO
•
JULY, 1958
a
SUbSidiary&~ystrom.
Inc . •
Benton Harbor 25, Mich.
7
easy-to-build
high quality
Look ... how simply you can
assemble your very ow n high fidelity
system! Fun-filled hours of shared
pleasure, and an everlasting sense
of personal accomplishment are
just a few of the rewards. Heathkits
cost you only HALF as much as
ordinary equipment and the quality
is unexcelled. Let us show you
how easy it really is! . ..
(,If Install a .001 "rdd18C condenser (rom socket
B7 (NS) to ground lug B11 (NS) . Cut the
leads 80 that they are Just long enough to .
reach anddres8 the condenser close to chas sis, over the wires already present.
Step-by-Step
AsseInbly
Instructions .
Read the step ...
perform the ope ration
.. . and check it offit 's just thaI si mple I
These plainly-worded.
easy-to-follow steps
cover eve ry assemb ly
operation .
Easy-to-follow
Pictorial
DiagraIns . . .
Detai led pictorial
diag rams in you r Heathkit
construction manua l
show where eac h and
every wi re and part is
to be placed.
Learn-by-doing
Experience
For All Ages ..
Kit construction is not
on ly fu n-but it is
educal iona l loa! You
learn about radio,
electron ic parts and
circuits as you build
your own equipment.
Top Quality'
NaIne-Brand
COInponents
Used in All Kits .. .
Elect ronic components
used i n Heathkits come
from we ll -known manufactu rers with estab li shed
repu tations. You r
assu rance of long life
and t rouble -free se rvice.
8
HEATHKIT
bookshelf 12-watt
aInplifier kit .:"'~~~~~'~~:2"':.
NEW
$27 95
...... ......... .
:-
Th ere are many reasons w hy this attractive amp li fier is a tremendous do ll ar va lue. You get many ext ras not expected at thi s
price leve l. Ri ch, fu ll ran ge, high fide lity sound rep rod uction
with low distortion and noise . .. pl us "modern" sty li ng. making it su itab le for use in t he open, on a bookcase , or end table.
Look at the featu res offe red by the model EA·2: full range frequency response (20- 20,000 CPS ± 1 db) wit h less than 1%
distortion over th is range at full 12 watt output- its own built·in
preamp lifier with provision for three separate inputs, mag
phono, crysta l phono. and tuner- RIAA equalization - sepa rate
bass and treble tone cont rol s- special hum cont rol - and it ·s
easy-to· build. Complete i nstructions and pictorial diag rams
show where eve ry part goes. Cabinet shell has smooth leather
texture in black with inla id gold design. Front panel features
brushed gold t ri m and buff knobs with go ld inserts. For a real
sound thrill the EA-2 will more than meet you r expectat ions.
Shpg. Wt. 15 Ibs.
TIME PAYMENTS AVAILABLE
ON ALL HEATHKITS
WRITE FOR FULL DETAILS
AUDIO
•
JULY. 1958
chairside enclosure kit
NEW
Thi s beautiful equipment enclosu re will
make your hi-fi system as attractive as any
factory-built professionally-finished unit. Smartly designed for maximum flexibility and compactness consistent with attractive appeara nce, this enclosure is intended to house th e AM and FM tuners
{BC-1A and FM -3A) and the WA-P2 preamplifier, along with th e
majority of record changers, which will fit in the space provided.
Adequate space is also provided for any of the Heathkit amp lifiers
designed to operate with the WA-P2. During co nstruction th e tilt-out
shelf and lift-top lid can be installed on either right or left side as des ired . Cabinet is constructed of sturdy, veneer-surfaced furnitureg rad e plywood ;/," and %" thick. All parts are precut and predrilled
for easy assembly. Contemporary available in birch or mahogany,
traditional in mahogany only. Beautiful hardware supplied to match
€ac h style . Dimensions are 18" W x 24" H x 35;/," D. Shpg. Wt. 46 Ibs.
CONTEMPORARY
....................
,
CE-1T Mahogany
Be sure to specify
model you prefer
TRADITIONAL
10 . . . . . . . . . . . . . . . . . . .
HEATHKIT
HEATHKIT
high fidelity FM tuner kit
broadband AM tuner kit
For noise and static free sound reception, this FM tune r is your least
expensive source of hi gh f idelity material. Efficient ci rcu it design
features stablized oscillator ci rcuit to elimin ate drift afte r warm-up
an d broadband IF circuits assure full fid elity with high sensit ivity. All
tunable components are prealigned so it is ready fo r ope ration as soon
as const ru ction is com pleted . Th e edge ·illuminated slid e rule dial is
clea rl y numbered for easy tunin g. Covers comp lete FM band from
88 to 108 mc. Shpg . WI. 8 Ibs.
Thi s tun'e r differs from an ordinary A M radi o in that it has been desig ned espec iall y for high fidelity. A special detector is in corporated
an d the IF ci rcuits are "broad banded" for low signal distortion. Sen ·
sit ivity and se lectivity are exce ll ent and qui et performance is assured
by a high signa l-to·n oise ratio. A ll tunable components are prealigned
before shi pment. In corporates automatic volume control, two outputs,
an d two antenna in puts. An edge- li ghted glass sl id e rul e dial all ows
easy tuning. Your "best buy" in an AM tuner. Shpg. Wt. 9 Ibs.
MODEL FM-3A $25.95 (with cabinet)
MODEL BC-1A $25.95 (with cabinet)
HEATHKIT
Dlaster control preaDlplifier kit
Des ign ed as th e " master co ntrol" for use with any of t he Heathkit
Willi amson-type amplifiers, the WA-P2 provides th e necessary compen sation, tone, and vo lume con trols to properly amplify and co ndition a
signal before sending it to the amplifier. Extend ed freq uency response of
± 1;/, db from 15 to 35,000 CPS will do full ju stice to th e finest prog ram
material. Features equali zati on for LP, RIAA, AES, and earl y 78 reco rd s.
Fi ve switc h-selected inputs with separate leve l con trol s. Separat e bass
an d treble co ntrols, and vo lume control on front panel. Very attractive ly
styled , and an exceptional dollar va lu e. Shpg. Wt. 7 Ibs.
pioneer in
"do-if-yourself"
electronics
HEATH
AUDIO
•
JULY, 1958
U~bSidiary of Daysfrom, Inc.
COMPANY
MODEL WA-P2 $19.75 (with cabinet)
. BENTON HARBOR 25, MICHIGAN
9
MODEL W-SM
MODEL W-6M
high fidelity am.plifier kits
To provide you with an ampl ifier of top-flig ht performance,
yet at the lowest possible cost, Heath has combined th e
latest design techniques with the highest quality materials
to bring you the W-5M. As a critical listener you will thrill
to the near-distortion less reproduction from one of th e
most outstanding high fidelity amp lifiers available today.
The high peak· powe r handling capabilities of the W-5M
guarantee you faithful reproduction with any high fidelity
system. The W-5M is a must if you desire quality plus
economy! Note: Heathkit WA·P2 preamplifier recom·
mended. Shpg. Wt. 31 Ibs.
HEATHKIT DUAL-CHASSIS
MODEL W3-AM
For an amplifier of increased power to keep pace with the
growin g capacities of your high fidelity system, Heath
provides you with the Heathkit W-6M. Recognizing that as
loud speaker systems improve and versatility in recordings
approach a dynamic range close to the concert hall itself,
Heath brings to you an amplifier capab le of supplying
plenty of reserve power without distortion . If you are look·
ing for a high powered amplifier of outstanding quality,
yet at a price well within your reach, the W-6M is for you!
Note: Heathkit model WA·P2 preamplifier recommend ed.
Shpg. Wt. 52 Ibs.
HEATHKIT SINGLE-CHASSIS
MODEL W4-AM
high fidelity am.plifier kits
One 01 the greatest developments in modern hi·Ii reproduction was
the advent of the Williamson amplifier circuit. Now Heath offers
you a 20-watt amplifier incorporatin g all of the ad vantages of
Williamson circuit simplicity with a quality of performance con ·
sidered by many to su rpass the original Williamson. Affording you
f lexibil ity in custom i nsta llations, the W3-AM power supp ly and
amplifier stages are on sepa rat e chassis allowing them to be
mounted side by side or one above the other as you desire. Here
is a low cost amplifier of ideal versati lity. Shpg . Wt. 29Ibs ..
HEATHKIT
high fidelity
am.plifier kit
MODEL A-9C
$35 50
For maximum performance and versatility at the lowest
possible cost the Heathkit model A-9C 20· watt audio
amplifier offers you a tremendous hi·fi value. Whether for
your home installation or public address requirements
this power-packed kit answers every need and contains
many features unusual in instruments of this price range .
Th~ preamplifier, main amplifier and power supply are all
on one chassis providing a very compact and economical
package. A very inexpensive way to start you on the road
to true hi·fi enjoyment. Shpg. Wt. 23 Ibs.
10
In hi s sea rch for the "perfect" amp li fier. Will ia mson brought to
the world a now· famous circuit wh ich, after eight years, still ac ·
counts for by far the largest percentage of power amplifiers in use
today. Heath bring~ to you in the W4-AM a 20-watt amplifier in,
corporati ng all the improvements resu lting from this unequalled
background. Th ousands of sat i sf i ed users of the Heath ·
kit Williamson·type amplifiers are amazed by its outstanding per·
forman ce. For many pleasure· filled hours of listening enjoyment
this Heathkit is hard to beat. Shpg. WI. 28 Ibs.
HEATHKIT
electronic
crossover kit
MODEL XO-1
One of the most exc iting improvements you can make in
your hi·fi system is the addition of this Heathkit Crossover
model XO-1 . This unique kit separates high and low frequencies and feeds them through two amplifiers into
separate speakers. Because of its location ahead of the
main amplifiers, 1M distortion and matching problems are
virtually eliminated. Crossover frequencies for each channel are 100, 200, 400, 700, 1200, 2000 and 3500 CPS. Amazing versatility at a moderate cost. Note: Not for use with
Heathkit Legato Speaker System. Shpg. wt. 6 Ibs.
AUDIO
•
JULY, 1958
NEW LOW PRICE!
"LEGATO"
high fidelity speaker systelll kit
Wrap yourself in a blanket of high fidelity music in its true form. Thfill to
sparkling treble tones, rich, resonant bass chords or the spine-tingling
clash of percussion instruments in this masterpiece of sound reproduction. In the creation of the Legato no stone has been left untLJrned to bring
you near-perfection in performance and sheer beauty of style. The secret
of the Legato's phenomenal success is its unique balance of sound. The
careful phasing of high and low frequency drivers takes you on a melodic
toboggan ride from the heights of 20,000 CPS into the low 20's without the
sl ightest bump or fade along the way. The elegant simplicity of style will
complement your furnishings in any part of t he home. No electronic knowhow, no woodworking experience required for construction. Just follow
clearly illustrated step-by-step instructions. We are proud to present the
Legato-we know you will be proud to own it! Shpg. Wt. 195 Ibs.
··...... ....................',
MODEL HH-1-C
(imported white birch)
MODEL HH-1-CM
(African mahogany)
.
·
, . . . . . . . . . . . . . . . . . . . . . . . . ... I . " ..... .
HEATHKIT
HEATHKIT
BASIC RANGE
RANGE EXTENDING
high fidelity speaker syste:m kits
MODEL
SS-2
$3995
A truly outstanding performer for its
size, the Heathkit model SS-2provides
you with an excellent basic high fidelity speaker system. The
use of an 8" mid-range woofer and a high frequency speaker
with flared horn enclosed in an especially designed cabinet
allows you to enjoy a quality instrument at a very low cost.
Can be used with the Heathkit "range extending" (SS-1 B)
speaker system. Easily assembled cabinet is made of veneersurfaced furniture-grade JI," plywood. Impedance 16 ohms.
Shpg. Wt. 25 Ibs.
Froo Catalog!
Don't deprive yourself of
the thrill of high fi delity or
the pleasure of building
your own equipment any
longer. Ou r free catalog
li sts our entire line of kits
with complete schematics
and specifications.
Send for it today!
HEATH
pioneer in
"do-it-yourself"
electronics
Designed to supply very high and
very low frequencies to fill out the
response of the basic (SS-1)
speaker, this speaker system extends the range of your listening
~~~~L
pleasure to practically the entire
range of the audio scrale. Giving the appearance of a single
piece of furniture the two speakers together provide a superbly integrated four speaker system. Impedance 16 ohms.
Shpg. Wt. 80 Ibs.
$99 95
COMPANY. BENTON HARBOR 25, .MICHIGAN
Djbsidiary of Daystrom, Inc.
o Please send the Free HEATHKIT catalog.
o Enclosed is 25c for the New HI-FI book.
name
address
city & state
ALSO SEND THE FOLLOWING KITS '
NEW! "DOWN-TO-EARTH"
HIGH FIDELITY BOOK
THE HOW AND WHY OF HIGH FIDELITY, by Milton Sleeper. ex pl ains what high
fidelity is, and how you can select and plan
your own syste m. This lib erally·illust rated,
48-oage book tells you the HI·FI
stOry without fancy t ec hnical
C
jargon or high-sounding ter-
QUANTITY
ITEM
MODEL NO.
PRICE
25
minology.
AUDIO
•
JULY, 1958
Enclosed find $..... .. .... . ... Please enclose postage for parcel post-express orders are shipped delivery
charges collect. All prices F.O.B. Benton Harbor, Mich. NOTE: Prices subject to change without notice.
.L-------------------------------------------------11
ere.
edward litnall Canby
The Tape Cartridge
OMES THE REVOLUTION! That is the best
way I can express my impressions of
the first demonstration to the audio
press of RCA's triple-threat line of stereo
goods for the coming season.
Disc stereo- of course. That we had expected, these many months. The new stereo
disc wasn't exactly a big secret.
Disc stereo players-to be taken for
granted. But there was a considerable gasp
of astonishment from the assembled press
when it was revealed that RCA's entire
line of new home phonographs (two heldover low-priced models excepted) would
go stereo, complete with stereo ceramic
pickup (RCA's own) and dual amplifier
set-up, and that t h e cost of these machines,
minus the extra speaker, would be only
about $10 mor e than eq uivalent items in
last year's line. (The second speaker, in
most models, is sold as an extra. You don't
have to play ster eo unless you want to.)
But the biggest news by far was the new
tape ster eo cartridge or magazine and its
matching player equipment. Rumors had
been afloat for quite awhile on this score,
too, but the details were kept unusually
well wrapped and few of us had any clear
idea as to what was afoot-though the
virtual cessation of RCA standard tape releases was a straw in the wind. (The system was shown to the tape r ecorder industry people very early in the yearthey managed to hold their tongues.)
And thus only a few of the pros in our
business were prepared for the extent of
the impact area, so to speak, when RCA
let loose its little cartridge bombshell in
the most casual manner.
(
Bombshell in a Cartridge
First-four tracks on a single tape, two
tracl,s each direction for "half-track"
stereo. This we knew about from previous
Ampex announcements, but few of us had
actually heard it.
P lus-so und quality not far from present 7% ips standards, on all four tracks,
at the slow speed of 3 % ips. We heard it;
I found it excellent. This represents a basic
improvement in the functional frequencyr ange-vs.-speed r atio_ (A r eporter asked
RCA point blank whether the sound recorded on th e new cartridges was "as
good" as that on present two-track stereo
tape. The auswer was an unequivocal
"yes." )
Plus-a tape magazine or cartridge with
two hubs, to right and left (no loops, no
tricky angles of tape f eed) that drops into
place in an instant on its own special
player, is operated entirely by pushbutton
contI' 01, yet has most of the ad vantages and
* 780 Gl'eenwich St., New York 14, N. Y .
12
flexibility of present home tape. (Unscrew
two screws, lift off the top half of the
car tridge, and the tape is out in the open
for patching, editing, adding new tape and
so on.) The cartridge is turnover; you flip
it to play back to the beginning. (Automatic players reverse its direction withont
the flipover.)
P lus- and this is the big pay-off- home
recording in cartridge form. T his is not
merely a new stereo tape phonograph. It
records, too, either monaurally or stereo.
You can buy cartridges of blank tape (or
reel your own) ; yon can r ecord on all four
tracks singly, one after the other- two
hours' playing time- or you may record
stereo for a full honr using two tracks
each direction. (I'm not much in favor of
this, however. Home stereo recordings are
apt to be nothing more than freakish
monstrosi tics. )
So, it was revealed, the RCA cartridge
system is actually an invader in every territory, with potentialities in each area that
could turn whole industries inside out. You
can see why a few of us, at least, wer e
slightly overwhelmed by the possibilities,
in what was surely the most offhand demonstration RCA has ever staged.
There's plenty to say about stereo disc
and about RCA's stereo players, but I find
the cartridge tape so much more significant
at the moment that I'll put all the rest
a side. Let me throw out to myself some
simple questions of th e sort that most people will be asking. Some may have been
answered specifically and in detail by the
time this is in print-but I'll take a chance,
on the limitec1 inf ormation we had at our
disposal, to give you a bird's eye picture
as well as I can.
Tape Mechan ism? The new tape playerrecorc1er is a minimnm departure from the
accepted anc1 familiar standarc1, even with
the cartridge in its middle. There are the
conventional controls, including fast motion in eithel' direction, for rewind or for
locating a wanted passage. The tape simply
moves from one sic1e to the other, as usual,
but within the cartridge. You can watch
the hub s turning and you can see the size
of the tape roll inside thl'Ough windows in
the cartridge body. The two hubs, about an
inch an d a quarter wide each, are set in to
two holes in th e body of the cartridge;
they turn on flanges at their edges. This
is a highly sensible "compromise" cartridge
-it sensibly avoids the complications that
arise when enc1less loops or offset r eels
are bronght into the picture. In effect, you
have here simply a removable section of an
ordinary tape transport system-two rolls
of tape already in place and a set of guides
to lead the tape in between to the right
place. The rest of the transport is in the
playing machine- the heads, the capstan,
the driving power. (B ut see below for size
and space.)
The whole thing, of course, is mac1e possible only by the extraordinary saving in
playing time that is the result of the slowspeed four-track system. Without that, the
cartridge would have to be far too big for
any practical use, in this two-reel form.
No wonder we haven't had it before now.
Accident-al erase? Beautifully taken
care of, in the taped cartridge recordings,
via an automatic safety switch actuated
when the cartridge is plugged into the machine. You can't go wrong. For home recording there is a simple "defeat" that allows the record-erase ci rcuit to be nsed,
at will.
Turnover construction? The RCA cartridge is made in two sy=etrical plastic
halves with slots along the lower side arranged so that the cartridge looks the same
on either side. Turn it over, plug it in the
other way up and you play your tape back
to the beginning, j ust as in present standard home tape. Fully automatic reversing is
a sort of afterthought; in this mechanical
configuration it was simple . enough to design a fancier player that would reverse
the play at the end of the reel, with a second head to play the r eversed tracks. The
idea is about the same as that in the
Web cor "no reel t ur nover" mo dels and
originates in the once well-known " Twin
T rax" machine that first promoted the idea
of dual tracks on home tape, many years
ago.
Tha tape cartridge, of course, is interchangeable on either type of machine, manual-turnover or automatic-reverse.
Tape stop? A crucial question in any
semi-automat ic pushbutton system for tape.
Will the tape stop at the end, without pulling loose inside the cartridge ~ Two diagonal slots in the cartridge body (symmetrical, to right and left, as usual) allow feeler
arms to sense tape tension, on each side,
stop the tape. (In automatic models, the
same device reverses the tape as well as
stopping it at the end of play.)
I didn't get a chance at the RCA demonstration to try a nasty little test I had in
mind-push the fast rewind button, then
wait to see what would happen at the end
of the reel. But RCA says the thing does
stop, won't break the tape or pull it loose.
You can take that with a grain of salt
if you want; but remember that RCA is in
for some tall trouble if the automatic stop
isn't what it claims to be! The first thing
any home owner will do will be to put this
to the test- by accident or on purpose. I
think we can assume that the auto-stop
featur e was one of RCA's biggest preoccupations, and that the present system is
pretty much foolproof. If not, RCA. had
better start running for covel'.
Tape spill?
The simplest of built-in
brakes, spring actuated, clamps down on
the t ap e automatically when the cartridge
is taken off the player. Plugging it into the
machine r eleases the brake. If you do manage to spill some tape, shaking the cartridge will often r eel it back inside, due to
the brake structure. I f not, you can remove the two screws in a moment, take off
t he top half of the magazine and re-reel
in conventional fashion. Since there's no
hand threading in this system, tape spillage is not likely to occur very often.
Cross-talk between tracks? A big question! All t hat I can say about it at the
moment, after one good hearing of stereo
cartridge sound, is (a ) iliat I couldn't
heal' any cross-talk and (b) RCA. would
not dare promote this system for singletrack monauml r ecording in the home if
(Continued on page 32)
AUDIO
0
JULY, 1958
the
experts say ___ in
High Fidelity the best buys
are
SZtWl,&;
1na"
KITS and WIRED
BETTER ENGINEERING Since 1945 EICO has pioneered the
concept of test instruments in easy-to-build kit form - has become world-famous
for laboratory-precision instruments at low cost. Now EICO is applying its vast
experience to the creative engineering of high fidelity. Result: high praise from such
authorities as Canby of AUDIO, Marshall of AUDIO CRAFT, Holt of HIGH FIDELITY,
Fantel of POPULAR ELECTRONICS, Stocklin of RADIO TV NEWS, etc. as well as from the critical professional engineers in the field.t
SAVE 500/0
Mass purchasing, and a price policy deliberately aimed to encourage mass sales,
make this possible.
EASY INSTRUCTIONS
You need no previous technical or assembly experience
EICO kit - the instructions are simple, step-by-step, "beginner-tested."
build any
to
DOUBLE 5·WAY GUARANTEE
Both EICO, and your neighborhood distributor,
guarantee the parts, instructions, Performance ... as well as lifetime service and
calibration at nominal cost . .. for any EICO kit or wired unit.
BEFORE YOU BUY, COMPARE
At any of 1200 neighborhood EICO distributors
coast to coast, you may examine and listen to any EICO component. Compare
critically with equipment several times the EICO cost - then you judge.
You'll see why the experts recommend EICO, kit or wired, as best buy.
tThousands of unsolicited testimonials on file.
HF60, HF50 Power Amplifiers
HF61 Preamplifier
HFS2 Speaker System: Uniform loading & natural
bass 30-200 cps achieved via slot-loaded split
conical bass horn
of 12-ft path. Middles & lower
highs from front side of 81/2" cone, edge-damped
& stiffened for smooth uncolored response. Suspen·
sionless, distortion less spike-shaped super-tweeter
radiates omni-directionally. Flat 45-20,000 cps, useful
to 30 cps. 16 ohms. HWD: 36" , 151f4", ll1f2" .
.. . . . rates as excellent ... unusually musical ...
really non-directional" - Canby, AUDIO. "Very
Impressive" - Marshall (AUDIOCRAFT). Walnut or
Mahogany, $139.95. Blonde, $144.95.
H"90 FM Tuner equals or surpasses wired tuners
up to 3X its cost. New, pre·wired, pre-aligned, tem·
perature-compensated "front end" - drift·free.
Sensitivity, 1.5 uv for 20 db quieting, is 6X that of
other kit tuners. DM-70 traveling tuning eye .
Response 20-20,000 cps::'::1 db. Cathode follower &
multiplex outputs. Kit $39.95*. Wired $65.95*. Cover
$3.95.
- _..
*Less cover, excise hx inc I.
lIF61A Preamplifier, providing the most complete '
control & switching facilities, and the finest design,
offered in a kit preamplifier, " ... rivals the most
expensive preamps . . . is an example of high
engineering skill which achieves fine performance
with simple means and low cost." - Joseph Marshall,
AUDIOCRAFT. HF61A Kit $24.95, Wired $37.95, H.F61
(with Power Supply) Kit $29.95. Wired $44.95.
HF60 60-Watt Ultra Linear Power Amplifier, with Acro
TO-330 Output Transformer, provides wide band·
width, virtually absolute stability and flawless tran·
sient response. " ... is one of the best-performing
amplifiers extant; it is obviously an excellent buy."
-AUDIOCRAFT Kit Report. Kit $72.95. Wired $99.95.
Matching Cover E·2 $4.50.
"F52, "F20
·' ntegrated Amplifiers
AUDIO
•
JULY, 1958 -
HF12 12·Watt Integrated Amplifier, absolutely free of
"gimmicks", provides complete "front end" facili·
ties & true fidelity performance of such excellence
that we can recommend it for any medium-power high
fidelity application. Two HF12's are excellent for
stereo, each connecting directly to a tape head with
no other electronic eqUipment required . Kit $34.95.
Wired $57.95 .
HF50 50-Watt Ultra·Linear Power Amplifier with ex·
tremely high quality Chicago Standard Output Trans·
former. Identical in every other respect to HF60 and
same specifications up to 50 watts. Kit $57.95. Wired
$87.95. Matching Cover E-2 $4.50.
HF30 30·Watt Power Amplifier employs 4·EL84
high power sensitivity output tubes in push·pull
parallel, permits Williamson circuit with large feed·
back & high stability. 2-EZ81 full-wave rectifiers for
highly reliable power supply. Unmatched value in
medium-power professional ampJifiers~ Kit $39.95.
Wired $62.95. Matching Cover E-4 $3.95.
HF·32 30·Watt Integrated Amplifier Kit $57.95.
Wired $89.95.
HF52 50·Watt Integrated Amplifier with complete
"front end" facilities and Chicago Standard Output
Transformer. Ultra-Linear power amplifier essentially
identical to f1F50 . The least expensive means to the
highest audio quality resulting from distortion-free
high power, virtually absolute stability, flawless
transient response and "front end" versatility.
Kit $69.95. Wired $109.95. Matching Cover E-l $4.50.
HFSI Two-Way Speaker System, complete with fac·
tory-built cabinet. Jensen 8" woofer, matching jensen
compression-driver exponential horn tweeter. Smooth
clean bass; crisp extended highs. 70-12,000 cps ± 6
db. Capacity 25 w. Impedance 8 ohms. HWD,
11" x 23" x 9". Wiring time 15 min. Price $39.95.
r-------------------I
MAIL COUPON FOR CATALOG
I
EICO® 33-00 Northern Blvd., L.LC. 1, N.Y.
Show me how to SAVE 50% on professional Test Instruments and High Fidelity.
Send me free catalog and name of neighborhood distributor.
HF20 20-Watt Integrated Amplifier, complete with
finest preamp-control facil ities, excellent output
transformer that handles 34 watts peak power, plus
a full Ultra-Linear Williamson power amplifier circuit.
Highly praised by purchasers, it is established as
the outstanding value in amplifiers of this class.
Kit $49.95. Wired $79.95. Matching Cover E·l $4.50.
Name ,.
Address
City ......
....Zone .. .. .. State
A·7
33·00 Northern Boulevard, L. I. C. 1, N. Y.
Over 1 Million fiCO instruments in use the world over.
13
EDITOR'S REVIEW
THE STEREO ISSUE
OT, IF YOU PLEASE, the issu e of whether or not we
will convert to stereo-we've already done thatbut the August issue of AUDIO which will be devoted entirely to stereo in all its aspects, or to as many
of them as space will allow. More about that later. But
first, a word from our own vast experience with stereo
records- all of two weeks by this time.
Forgetting about the stereo effect itself, let us consider what happens when we playa monaural (mor e
about that later, too) record on a stereo system. Believe
us, if you will, when we say that mono . . . (no, we
won't say it ) records invariably sound better on a
stereo system, played by a stereo pickup, than they do
on a ... single-channel rig, even though the same two
speakers may be playing. Try it out for yourselves.
And now, back to the story.
We believe you will find something of interest in next
month's issue, both theory and constructional material.
We have just finished a survey of all FM stations
throughout the country and we have compiled the results of their thinking with regard to ster eo, and more
particularly with regard to their future intentions toward FM/ FM Multiplex as the logical means for broadcasting stereo in a manner which will permit the FM
listener who does not have the multiplex adapter to
receive a well balanced program, rather than just one
half of a two-channel program which is just what
listeners to either AM or FM alone hear when a
conventional stereo tape is played. We also have
some interesting material on the type of device used
for multiplex r eception in conjunction with an FM
receiver, as well as a short discussion of the difficulties
encounter ed in actual practice.
In addition to a full complement of articles on the
subject, we are augmenting the NEW PRODUCTS section
to bring detailed information regarding the equipment
that is now available for home use in ster eo reproduction. And we also plan on a listing of all the stereo
r ecords which will be on the market by that time. Unfortunately we cannot include all stereo tapes, but those
listings are already incorporated in the monthly record
guides, and in at least one quarterly.
We trust you 'll be seeing us next month.
N
is monaural, unless perhaps some few have tried to
shave with a straight razor in a dark room or put an
ear too close to the lawnmower and then left it there.
At an IHFM meeting during the Los Angeles High
Fidelity Show in February, Paul Klipsch dropped one
of his not infrequent bombshells by introducing the
term "monophonic" to describe a single-channel system. Everyone knew just what Mr. K. meant without
needing to have it explained, but it does not seem to
have caught on at all, even though t her e is good r eason
for it.
vYe may be slow, but anyhow we have decided that
"monophonic" has finally caught on with us, and
beginning with the August issue the term monaural
will join our small but select list of taboos, r ating the
third place. ('l'he other two taboos are: " must," when
used as a noun, e.g., "the use of wirewoul1d resistors is
a m u.s t' , ; and the suffix "wise," used in place of more
correct English to imply " from the standpoint of,"
e.g., " businesswise this is not a good policy. " ) We do
not believe that either of these last two taboos has
gotten into print in the editorial material in this
magazine for years; we can't censor the ads, of course,
and not everyone agrees with our idiosyncrasies. Actu, ally, we see no reason why a semi-technical magazine
must perforce shun the niceties of proper English.
This bring's up another question-one about which
we are on the fence, so to speak. This is the use of the
letter " K" to mean thousand. We have long standardized, in drawings made by our own draftsmen, on
written-out values from 0 to 99,000, and on values from
100,000 up we have always preferred to use the decimal
part of a megohm, as 0.27 Meg. W e can't blame the
draftsmen for this (either way ) since for about three
years all our drawings have been letter ed on a typewriter, using a simple process we believe we originated,
and by an editorial assistant. The style is, therefore, of
our own choosing. Actually, the "K" is somewhat
shorter, but we have always felt it was not so precise.
Putting the question to you readers is, perhaps, a
cowardly approach, but you are the people we strive
to please. Some of you may have preferences one way
or the other and we would like to know about them.
Comments, anyone ~
MONOPHONIC REPRODUCTION
SIC TRANSIT GLORIA VIOUNO
vYithout question, the term "monaural " has been
used incorrectly ever since someone needed a term to
describe the opposite of " binaural. ' , Years ago we took
a firm stand against binaural in any application except
when it r eferred to reception of a two-channel signal
directly to the individual ears by means of headphones.
W e were almost stumped when someone brought out a
wing chair with a small speaker in each wing, because
this is practically the same as binaural. Anyhow, we
have stuck to the strict usage of "stereophonic" when
it r eferred to rep~'oduction through loudspeakers both
of which could be heard by both ears, and this 'seems
to be almost solic1ly established throughout the industry
by now. Only rarely do we encounter binaural when
stM'eophonic is meant.
"Monaural " is an entirely different matter. No one
Almost never does a new-product publicity release
get mentioned on this page, but this one we can't pass
up.
The first paragraphs of a release from the agency
r epresenting John J. Calborn Company, 1551 Thames
Drive, Columbus 19, Ohio, read:
"Faced with the loss of a big percentage of their
market, due to heavy competition from foreign imports,
America's only violin factory (italics ours. ED. ) is now
producing a line of instruments designed to be seen
and not heard.
"The firm's new " Flowering F iddle" planters are
genuine violins made to be hung on walls. They contain
a cleverly concealed waterproof cannister to hold trailing vines, ivy, or small flowering plants."
Could someone be stringing us ~
14
AUDIO
•
JULY, 1958
NEW
DIODE
SPEEDS
VOICESAT 6,000,000,000
c. P. S.
How the radio art can be improved through solid state science is illustrated by a recent development at Bell Telephone Laboratories. To make
voice signals travel by microwaves they must first be "converted" -caused to
vibrate at billions of cycles per second. To date, it has been possible to
accomplish this conversion only at the cost of appreciable loss of signal energy.
Could a more efficient converter be provided?
In the field of solid state science it was known-as a laboratory curiositythat semiconductor diodes can be made not only to convert the frequency of'
signals, but also to amplify them. At Bell Laboratories Dr. Arthur Uhlir, Jr.,
and his associates calculated that this amplifying action could be put to practical use. They proved the point by developing a junction diode converter
which can deliver up to 40 times as much signal energy as previous converters.
This efficient new converter will be applied in a new Bell System microwave highway able to transmit thousands of telephone conversations and a
dozen television programs simultaneously at six billion cycles per second. In
other forms it is being developed, under Signal Corps contract, for radar and
military communications where more efficient frequency conversion can also·
be used to advantage.
This development is an example of the many different ways in which
Bell Laboratories works to improve your telephone service and communications
at large.
@
~.n"r#
BELL TELEPHONE LABORATORIES
WORLD CENTER OF COMMUNICATIONS RESEARCH AND DEVELOPMEN,
Improving the Tape Amplifier
HERMAN BURSTEIN';' and HENRY C. POLLAK
Changes in components often necessitate changes in circuit values in order to ensure
optimum operation and to take advantage of the potentially improved performance. The
authors' earlier tape amplifier is here brought up to date to permit the use of improved heads
A
tape r ecorder amplifier was described in the January
and February, 1957, issues of this
magazine by the writer s; the circuit is
reprinted here as Fig. 1. Since then, th«;!
writers from time to time have made
changes in the amplifier to improve its
performance or operating convenience .
The number and nature of changes that
have accumulated now seem to warrant
another article indicating ho w satisfac-
HIGH- QUALITY
* 280 Twin Lane E., Wantagh, N. Y.
tory p erformance may be won from the
electronics of a tape recorder.
The changes concern installation of
professional heads, a more stable oscillator, more accurate equalization, reduced noise and hum, and greater con-
Fig . 1. The original circuit of the tape recorder amplifi e r as described by the author in the January and February, 1957, issues.
8 +
2
Use tube shield
VI
6AU6
;;;
o
V3
In 12AX7
C4
CI
;;;
C6
(Selected)
<:10
.01
CB
Shiel d gridpin
.
C5
." ,
E
g-
M
g
M
E
;;;
'"
§~
o·
'"
0 .25
.
...
S
RI2
120~
g0()
;;;
Ceramic
E
§
'"
'"
d
PLAY-RECORD HEAD
aM
;;
E
'"
CII
0.5
.01
R13
0.47 meg
0.1 meg
rI
PLA Y
•
Sib
~
.~
S
~
(FRONT)
IVC"'"
~~
~
o
t----- I
~:
2
JI MIC.
J2 RADIO-I
I
I
RECORD
Sic
.52
Record
Sid
I
I
I
:
R27
27,000
ERASE HEAD
I
I
(
50,000 BIAS POT
Low-capacitance cob le
R28
~&--+--------------~-------------"I
r---------- - -----------------------~
L2 Nate 4
I
CI7
120~~f
------~
B3+
.
ceramic
f~
R33
MOTOR
8 2+
2
~--C:""'I..J 0 .----:-:-:-_ _ _ _ _ _..J
0
.§.
I
R32
I
51,000
.... 1
J3 RADIO-21
(REAR)
3.75 ips.
_ ________________ J
L_
I
I
I
r
Equal'n ':'
I
0 7.5 ips.
C24
4700
C23
15/ 350J
15/ 350
~
-'
c
JS OUTPUT
..'?
(6\---'
~OO2
~
ceram ic
1 'omp slo w-blow fuse
Heaters and Pilot light
117 VAC
Note 1: If ban response is e xceni ... " due to the playback head characteristic, boss
may be reduced by ,,!sing R6 with a val ue in the range from 0 . 1 to 0.5 meg .
If basds insufficient, connect the .035-J.lf capacitor C2 to the plate of VI
instead or to the for side of the O.I-J.lf coupling capac itor CI. See text.
Note 2: TV width coil variable from approximately 5 to 35 mh o Ram 201 R3A or eq .
Note 3: Approximate value is 5 meg . Should be varie d to produce correct indication on record-level metor or VU meter .
Not. ,, : Oscillator tran,rorme r used is a shiel ded unit furnished in Pentron HFP-l
omp\i fi~ r and other Pentron models . TU'1ed to approximotely 65 kc; see
text. A suitable coil (port No . 0501) may be obtained from Dynomu Mognetronics Corp., 21 N. Third St., Minneopolis, Minn . , in which cose the
recommended Oynomu oscillotor o.ircuit should be employed.
AUDIO
•
JULY, 1958
Note 5:
11
is a shielded power Iramfarmer. 240-0-240 v otSOma, 6.3 v at 2. 5 a.
Merit PJO.(7 or e quivalent .
Changes os discussed in the te xt:
C6 becomes 50
wf
Nate 6: Adjusted for 0 .68 mao See text.
Cl1 Is omitted
Note 7: Oynamu heads . See Note ~ for compony oddrets.
C 13 becomes 100 iJiJf
Misc. :
Resistors RJ ond R", are low-noise types. Others are Ih-watt, 10% tolerom:;:e unles.s otherwise specified. Capacilors if'! ... r, at le051 <400 v. roting ,
popet or ceramic, unless otherwise specified. Switch 51 : "'-circuit, d.t .,
lever or rotary type. 52: toggle Of slide. 53 : on V.C. S", : toggle. Jocks :
J, and J2, shorting-type phone jocks; J3 arid J4, lIondord phone jad(s.
J5, pin- plug receptacle ("phono" iack) .
C15, C16, and CIS become
silver mica instead of
ceramic
RI8 becomes 20,000 ohms
R2 1 becomes 0.22 meg
R27 is omitted
17
directly from R 28 • Bias iYHS H~l .inste:i tor
0.7 ma., as measmed on an audio VTVM,
by r eading voltage across a 100-ohm
r esistor inserted between ground and the
ground lead of the head. This r epresented an optimum compromise affording satisfactorily low distortion and extended high-freq uency r esponse. More
bias current would have further r educed
distortion at high recording levels, but
would have caused treble r esponse to
cleteriorate significantly. At the bias used
by the writer, recordings sound clean,
and if at 7.5 ips one A-B's tape recording of a hig h-quality phono disc with the
disc itself, the two are virtually indistinguishable.
'fhe Brush BK-1UO half -track erase
head was used. For the voltage and
CUlTent produced by the bias oscillator
in Fig. 1, the head appeared to work
most efficiently with its windings connected in parallel. Current was supplied,
as before, through the l20 - ~/-lf capacitor
C17 and measlU'ed 12 rna., which is
enough for effective erasure with this
head. Erase current was measured by
r eading voltage across a 100-ohm resistor between the head and ground.
The 100-ohm resistors employed to
measure bias current through the record
head and erase current through the
erase head were left permanently in
p lace. This facilitates quick checking of
bias CUlTent and erase-head operation.
It is on ly a matter of seconds to connect the audio VTVM across these re-
venience in switching fr0111 r ecord Lo
playback.
Installat ion of New He a d s
The design of the original amplifier
was partly based upon use of Dyuamu
heads. When the Dyuamu record-playback head had worn to the point where
replacement was necessar y-the gap
having widened and high-frequency r esponse deteriorated-it was decided to
replace this and the er ase head with
Brush heads, which ru:e in extensive
professional and semi-professional use.
The Brush BK-1090 r ecord-playback
half -track head was used. It is of laminated-cor e construction , which minimizes
eddy cUlTent losses ; has a nominal
.00025 in. gap , permitting good r esponse
tc 15,000 cps at 7.5 ips; and has two
coil windings, which are hum cancelling
when properly connected in series or
p arallel for the a udio signal. It was
found that the Brush BK-1090, with its
windings in series for maximum p layback signal, had gr eater drive r equirements than th e Dynamu head, so that
more voltage gain was requir ed in recording. Therefore V 9 was converted
from a cathode follower into a voltage
amplifier stage, as shown in Fig. 2; at
the same time, equaliza tion was changed
f rom losser to feedback type, as will be
discussed later in more detail.
To obtain enough bias CUlTent through
the new head, the 27,000-ohm resistor
R 27 w as omitted and bias was taken
sis tors and take current readings . Occasionally, as the oscillator tube ages or
when it is replaced, it may be necessar y
to adjust bias current by means of R u .
The r ecordist desiring top-quality r esults will want to maintain watch over
bias cmrent as l'eligiously as he cleans
the heads and guides, demagnetizes the
heads, lubricates the tape mechanism,
and so on.
Upon installation of the Brush r ecordp layback head, the treble boost requirement for recording purposes appear ed
to change somewhat. The 10,000-ohm
resistor R18 was replaced by a 20,000ohm one, which p ermitted the series
resonant circuit comprising Ll and C 9
to produce a gr eater amount of treble
emphasis. At the same time, the 2 00-~~~f
capacitor C 6 was replaced by a 50 -/-l/-lf
capacitor, shifting upward the frequency
at which treble boost begins. Th e net
r esult was in a steeper treble boost.
Oscillator Circuit Changes
Bias current is fairly critical at sp eeds
of 7.5 ips and less. Relatively small
changes, less tban 1 db, ca n appr eciably
affect high-frequency response an d distortion, which both vary inversely with
bias. Thus a stable oscillator is much
to be desired. Toward this end, cer amic
ca pacitors C15) C16) and C18) all .002 ~Lf,
were r ep laced by silver mica units, which
are more stable over time and with temperature changes.
VI
. . . - - -......--83+
~----------------------~~------~p-8~
ECC83/12AX7
RECORDING CIRCUIT
(JUNCTION OF «" R13)
RECORDING-LEV EL METER
DR IVER (R20)
M O N ITOR JAC K (J .. )
R103
I
I
I
I
I
I
C102
,r~
r-------- _!J
J2
~
. I
RI07
8200
R PeR
Sic
.
81+
REC. HD. DR. PLATE RES. (R 15)
BIAS OSC. (C. T. OF L2)
METER DRIVER (V5 PLATE)
Sid
.
__
RADIO
J5
RECORD-HEAD CONSTANT-CURRENT RESISTOR (RI9)
BIAS CURRENT (R28)
RI09
o~p~(~r-----------~VVVV----------------------~
RECORD-PLAYBACK HEAD
• DEPOSITED-METAL-FILM RESISTOR
OR EQUIVALENT LOW-NO ISE TYPE
Fig . 2. When the amplifier is converted as desc ribed, it results in this arrangement.
18
AUDIO
•
JULY, 1958
Recording-Level Meter Circuit Changes
By providing mOre gain in th e early
stages to satisf y the greater drive r eq.uirements of the new r ecord head, more
signal was also presented to the grid of
V 5) which drives the r ecording-level
meter. Therefore it became necessar y to
red uce the signal reach ing the gTid of
V s so that the meter would give the same
indication as before for a g iven amount
of signal ?·eco1"Clecl on the tape. Accordingly, the 5-meg resistor R zl ) pad of a
voltage divider, was decreased to 0.22
meg, which caused the r ecording -level
meter to be correctly driven. Thus the
meter continued to indicate full scale
for a signal about 6 db lower than that
req uired to p roduce 2 per cent harmonic
distortion on the tape at 400 cps. As
explained in the original article, the
meter is set " 6 db ahead," so t o speak,
to make allowance for the fact that thE'
meter indication falls behind the actual
level of rapid transients.
R edu cing R 21 to 0.22 meg made it
necessar y to increase the bypass cap acitor C /S) which prevents bias current
from affectin g the record-level indicator.
Originally 12 ~L~Lf, it was increased to
100 ~L~f. On the other hand, t he 1 2 0-~~l'
capacitor C w al so used to shunt bias
current to gr ound, was found no longcr
necessar y a nd therefore r emoved.
Originally the p late of V 5 was permanently con nected to B I + so that the
meter would op erate in record as well
as p layback. This permitted comparison
of playback levels among various tapes
and enabled one to corr elate audible distortion with r ecorded signal level. Unfortunately, if a signal were fe d into
the amplifier for r ecording purposes but
switch 8 1 was left in the p layback mode,
the meter gave an indication as though
ever y thing were set for r ecording. For
this r eason the writer accidentally failed
on a number of occasions to obtain a
desired off-the-a ir recording . Th erefore
it was decided to obtain B+ for V,; from
the same point as the B+ supply for th e
record-head drivel' VI, and th e oscillator
V 6 ) which are connected to B + only in
the r ecord mode. This point is the arm
of 8,,() as shown in Fig . 2.
Revised Vz-V s Electronics
Th e circuii revision s in Fig. 2 meet
the fo llowing objectives : (1) V s is converted from a cathode follower to a
voltage amplifier to provide the gr eater
gain needed in recording. (2) Output
impedance is kept low through n egative
fee dback, thus maintaining higb-frequency response and permitting a reasonably long run of cable between the
tape r ecorder and the next component
in the audio chain for p layback (usually
a control amplifier) . (3) 1'he volu mecontr ol setting do es not affect pl ayback
eq ualization; in the or iginal circuit,
which employed a losser type of bass-
AUDIO
•
JULY, 1958
Fig . 3 . Rev isi on to
incre a se pla yb ac k
gain by re storing
VI to the circ u it.
REC- PLAY
HEA D
boost Jl etll·ork, boost at the very low end
dropped a few db wh en the gain control
was not at maximum setting . (4) Hum
and noise generated in V z and V s are
r educed by negative fee dback.
The feedback equalization network,
comprising R l o Q) R l o S) R l o r ) R l 08 ) and
C102) produces a playback characteristic
conforming very accurately to the
NARTB curve. C102 a nd R l o2 plus R l or
in ser ies produce the higb-frequency
turnover of 3180 cps, while C102 and
B l 08 produce th e low-frequency turnover
of 50 cps.
On e of the problems in using fee dback
to obtain a n equalization curve with a
large amount of bass boost, such as the
NARTB cur ve r equires, is that at low
frequencies the curve tends to lose its
accuracy. That is, gain at the low end
no longer varies exactly in inverse proportion to the amount of feedback. The
fee dback factor (ratio between gain
'w ithout feedback and gain with feedback) is 1 + AB) where A is gain beforc
fee dback and B is percentage of ou tput
voltage fed back. At high frequen cies,
the quantity AB is much greater than 1,
so that the f eedback factor consists
lar gely of AB j since A is a constant,
it can be said that the gain ratio varies
essentially with changes in B. At low
f r equencies, however, B is very small ,
and the quantity A B begins to approach
1. Th erefore the value 1 can no longer
be ignored in the expression 1 + A B.
And the r esponse curve no longer varies
exactly with changes in B . In order to
keep the qu antity A B significantly higher
than 1 (at least fo ur times as great) and
thus produce accura te equalization, it
would be necessary to incr ease A) that
is, gain before feedback. This can be
done by positive feedback. The O.l1-meg
r esistor RiO s in Fig. 2 produces several
db of positive fee dback for this purpose.
It should be noted that R l 09 ) a O.l-meg
r esistor, has been added in series between
the ou tput stage and the output jack J 5 •
A r esistor of this sort (about 10,000
ohms) al so should have appear ed in the
original cir cuit (Fig . 1). If the output
of the tape r ecorder is left connected to
a con trol amplifier, usually this output
will be shorted to ground by the contr ol
amplifier's f unction switch when this
switch is turned to another input source,
say the FM tuner. The purpose of R l os
is to prevent the sig nal at the p late of V s
from being shorted out durin g recording.
Revised Switching
As pointed out in the original article,
the hardware employed was that found
in a P entron HFP-1 tape amplifier. This
included the f unction switch, a fo ur-pole
double-throw type. B ecause of the
limited number of poles, when switching
from r ecord to pl ayback it was necessary
to remove the phone p lug that had been
ilJserted into the input j ack J z for recOl·ding from a high-level source, such
as the tape output j ack of a control
amplifier. If the p hone p lug wer e left in
during playback, it would p rovide a
fee dback path from the tape outpu t
jack of the control amplifier to the taper ecorder input and from t he t ape-recorder output back into the input of the
control unit.
Having to iDsert and remove the phone
plug con tinually proved to be a nuisance.
Therefore the revised switching arrangement of Fig. 2 was used, -which enabled
the phone p lug to be left in J 2 during
p layback. V l is now p ermanently connected to the microphone input jack J j •
Only V 2 and V s are used for playback;
more will be said about this shortly. In
p layback, the volume control R 8 and the
iuput j ack J z ar e disconnected from the
circuit by 8la" Prior t o this change, the
gain control had always been left in
maximum position during p layback.
Sin ce the change, the lack of command
over p layback gai n at th e ?·eco?·cle?· (gain
is governed by tbe control am p lifier) has
ca used no in convenience.
The function of S j b l·emains that of
introducing playback equalization, but
19
in a different manner from the original
circuit. Now SIb p laces C, o. across R IOB }
resulting in the NARTB characteristic.
When C10 2 is out of the circuit in the
record mode of the switch, there is an
equal amount of feedback at all frequencies.
There is no change in the purpose 01'
action of S W ' Some alteration was made
in S 1(Z' Now the record terminal instead
of the arm is connected to B,+, 'rhe arm
goes to the plate load resistor of V.} the
plate of V 5} and the plate of V 6 via the
center-tap of L •. The play terminal of
SId} previously not used, is now connected to ground as a means of bypassing stray bias current.
Using only V.- V 9 as a playback amplifier results in an output signal of
only about 0.1 volt or slightly less on
peaks. For many or most audio systems
this should be enough. A number of control amplifiers have high sensitivity, enabling them to produce an output of 1
volt or more for input signals of 0.1
volt. And the typical power amplifier
can be driven to full output or to within
a few db of full output by an input
signal of 1 volt.
However, if more playback gain is
needed, VI can be restored to the circuit
as in Fig. 3. Switch S Ia is used to transfer the grid of VI between the playback
head in p layback and the microphone
input jack J I in r ecording. The grid of
V . goes directly to the gain control RD
instead of being switched to this control
in recording and to the playback head
in playback. But if VI is used for playback, it is again necessary to remove the
phone plug from J. in this mode.
If VIis used in the playback cn:cuit,
the tape recorder preferably should be
operated in p layback with the gain control at maximum. Level should be reduced subsequently by the input levelset and/or gain control of the control
amplifier to which the tape machine is
connected. Thus when the playback
signal is reduced to the desired level,
noise and hum in V . and V s are simultaneously attenuated. The chances of
overloading V . are small when the gain
control of the amplifier is at maximum.
The signal from the p layback head is a
few millivolts at the most. Since VI has
less than 40 db gain, the signal presented
to the grid of V . with the gain control
full on is less than 1 volt. V 2 can easily
handle this with low distortion, especially because of the large amonnt of
negative feedback applied to its cathode.
Feedback is greatest at high frequencies,
where the output of the tape head, a
velocity device, is also greatest.
Reduction of Noise and Hum
To reduce noise, deposited-carbon resistors were used at the plate and cathode of VI and an oversize resistor (2
watts) at the plate of V . in the original
20
CHASSIS WALLS
SHIELD MADE
OF TINPLATE
Fig. 4. Physical arrangement of shield
and circuit components to minimize hum .
cn·cuit. In the circuit of Fig. 2, however,
deposited-metal-film resistors are used
for noise reduction. These can be virtually as noise-free as wirewound resistors
and about one-third as expensive, costing about one dollar each. Moreover,
wirewound resistors have some residual
inductance, although wound in a manner
designed to cancel inductance. This may
lead to pickup of hum 01' possibly to
pickup of the audio signal and consequent positive feedback and oscillation
in a high-gain circuit.
In view of the fact that depositedmetal-film resistors are not too readily
available to the individual hobbyist, it is
appropriate to mention here that the
Davohm Series 850 resistors, covering
the range of 2 to 850,000 ohms, are
carried by Harvey Radio, 103 W. 43rd
St., New York City. The writer has also
obtained excellent results with the Nobleloy deposited-metal-film resistors made
by Continental Carbon, Inc., and with
the S20 r esistors recently introduced by
Corning Glass Works.
In Fig. 2, deposited-metal-film l'esistors are used as the plate and cathode
resistances for V" V.} and V s' Prior to
use of metal-film types, deposited-carbons had been tried for V 2 and V s as
well as VI ' But each tilne a metal-film
resistor was substituted for a depositedcarbon one, there was a striking improvement, even in late stages. This is
not to say that all deposited-carbon resistors are inferior to metal-film ones.
In fact, the writer has been given to
understand that there are some depositedcarbon resistors of foreign make which
have excellent noise characteristics,
closely approaching those of wirewounds.
However, his personal experience with
American-made resistors has been that
deposited-metal-film ones have given far
bettel' results than the deposited-carbon
type.
It may be wondered why the cathode
resistors, whose values are quite small
compared with the plate resistors, should
also be low-noise types. However, when
the cathode resistor is unbypassed, as in
Figs . 1 and 2, its effective value is increased by the amplification factor, ~t,
of the tube. Thus if the ~ of V. is 36,
then the 2200-ohm cathode resistor is
effectively increased by 36 x 2200, or by
79,200 times. The total effective value is
the actual 2200 ohms plus the 79,200
iDcl'ease, or 81,400 ohm.
This can be explained as follows.
Assume that the noise voltage produced
by the cathode resistor is 1 per cent of
the voltage across the resistor due to
tube current flow. The grid-cathode voltage changes accordingly, since the cathode resistor is unbypassed, and the
voltage change is amplified ~ times by
the tube. So far as the output of the
tube is concerned, this is equivalent to a
1 per cent noise voltage in a resistor ~
times greater than the actual cathode
resistance. In effect, the cathode resistance is increased by ~ times its physical
resistance. Adding the increase to the
actual cathode resistance, the total effective value is ~ + 1 times the physical
resistance.
To reduce hum, V . -V s was enclosed in
a tube shield. Underneath the socket, a
shield, fashioned from a piece of tin can,
was mounted as shown in Fig. 4 to isolate
the grid of V. from heater leads and
other possible sources of hum. The shield
was soldered to the center pin of the
socket and grounded to the main ground
point A at VI (Fig. 1). All components
in the circuit of V2 -plate resistor, cathode resistor, positive-feedback resistor,
and coupling capacitor-were mounted
between the shield and the side wall of
the chassis. The cathode l'esistor RIO !
was grounded to the shield, while insulated leads were used to run the other
components to the appropriate points.
Another hum reduction measure was
to shield the power transformer with
silicon steel I-strips from a junked
power transformer. Cellophane tape was
used to bind the strips together. The
transformer is located in a corner of
the tape recorder, as far away as possible from the electronics and heads.
By this tilne, hum was virtually nonexistent so far as the antplifie1' p1'oper
was concerned, being virtually inaudible
at correct setting of the hum balance pot
R. 9 • However, the playback head picked
up a slight but noticeable amount of
hum from the power transformer, mostly
third harmonic (180 cps). In the original
amplifier a "gilnmick," consisting of a
silicon steel I-strip doubled in hairpin
fashion and clamped to the head bracket,
was fairly effective in warping the hum
field at the head. But this did not con(Continued on page 47) ·
A.UDIO
•
JULY, 1958
Transistor Beta Tester
With Linear Scale
SERGIO BERNSTEIN ':'
Tube testers are accepted as necessary units of test equipment. Increased
use of transistors makes some means for testing them almost imperative,
and this design gives a direct reading with a minimum of manipulation.
T
instrument
has a linear, direct-r eading dial and
two "beta" ranges. The accuracy can
be made as high as one per cent depending on t he components used, while the
cost of the instrument is relatively low.
Basically, the circuit! is that of an
oscillator. The point at which oscillation
starts is determined by the ~ of the transistor and by a potentiometer R} in Fig.
1. The frequency of oscilla tion which lies
in the audio range, depends mostly on
the transformer characteristics.
Let us call om' llUl1lmUm value of ~
by the term ~Illill' Then our maximum
va lue, ~maX! will be ~min + 100.0 sin ce,
after 10 tUl'llS, the dial will read 100.0
divisions mO?'e tha n at its initial position .
Let us call R rnin the total circuit resista nce, including the transformer primary r esistance, when RI equals zero.
Let us call R p the total r esistance of the
potentiometer.
Th en using Eq. (1) we can write the
following:
HIS SIMPLE AND LOW-COS'l'
N,I
!"
To understand the operation of the
circuit, let us examine th e conditions
which prevail when the cir cuit just begins to oscillate : (see F 'ig . 1)
let N::: Transformer turns ratio
I e= a.c. collector current
Ib = a.c. base current
~ = the base-to-collector current gain
'0l e have :
I
IJ + I g=Ic; and Ib =]j( I})
Also:
Then:
(1 +
L = I}
"
=--.!~
RI
RJ) . I
R'
I
1+Ro
0,
I
Therefor e:
b =-
I~(_l
1I 1 RI
+-
)
Ro
sin ce
we see that
., 205 S01tth B1'oadway, T arrytown, N.Y .
G. F. Montgomery, "Transistor beta
tester." Elect1'onics, May, 1957, pg. 198.
1
AUDIO
•
JULY, 1958
I"
RI
...
Theory
"j
(2)
Ib
~"'''.v =100.0 + ~.",;n =N ( 1 + R mi;: Rp} 3)
Fig . 1. Simpli e d schematic of basic arrangem e nt for testing transistors.
Combining (2 ) and (3) :
100.0 + (N)
(1)
Th erefore, fo r a given transformer
ratio and a given transistor ~, the circuit will start oscillating only when R 1
is above a certain critical value, given by
the relationship of Eq. (1) . Thus the
potentiometer R} can be calibrated to
read ~ directly.
Let us investigate the circuit further
to see what other useful relationships we
ean determine, and how we can make a
linea?', direct-reading, dial scale. Suppose
we make the r esistor RI a 10-turn potentiometer , and we use a 15-tmn dial such
as a Beckman typ e " RB" (or other similar device) to r ead out our ~ values directly . This dial has 100 major divisions
pel' turn , a nd a total of 15 turns or 1500
divisions. If we determine the m 'i nimwn
~ value we wish to read, we automatically
set the mCt.'c imum value of ~ we can read
on one range. This is true since our r esistor RI in F 'ig. 1 goes from a minimum
value of zero ohms to its maximum value
when rotated the f ull 10-turns, and ~
varies with RI according to Eq. (1).
(1 +
R m .;,, )
Ro
=
Therefore:
and
(4)
This equation gives the relationship
necessary to get the correct dial r eading
for ~ mi'" and ~ma", for a given N, RO}
and B7l' Note that this rela tionship is independent of R""ill'
If we substitute Eq. (4) back into Eq.
(2) we get:
~mi,,=N
+
Rmil>
x 100
R
(5)
p
'f his equation tells us what the minimum value of ~ is we can r ead, with a
given tm'ns r atio N, R m i l " and RIJ'
From Eqs. (2) and (3) we note an important property of this circuit, namely :
we can cbange the range of ~ readings
21
z '"
O~
-:.:
!;(o
;oz'"r::
~w
0",
U
•
o
ujl-
Rl
20.000 -10 turn " R2 500
::l
~
~
C
EXTERNAL
DETECTOR
".oR SINGLE-TURN POTENTIOMETER. SEE TEXT
_
Fig. 2. Complete schematic of transistor tester. R, may be a sp e cial 10-turn potentiometer, used with a 15-turn dial, although a singl e-t urn four-watt type af pot may
be used instead .
directly by changing only the transformer ratio N. Thus, if we use a multitap winding in the base circuit, h aving
tr ansformation r atios of Nand K N , we
can have two r anges of ~ namely : f rom
~mi" to (100 + ~mi" ) and from K X (~'ni" )
and f rom K x ( ~mi" ) to K x (1 00.0 +
~mi" ) ' All we have to do is multiply 0UI"
dial r eading by the factor Ie
Having established the r elationships
which govern the operation of this circuit, a practical form of it can be designed as in F ig. 2.
To keep the cost at a minimum, the
surplus market was scanned, and it was
f ound that 10-turn, 20,000-ohm, potentiometers were available. Rp then is 20,000 ohms.
Next T 1 was chosen so as to get two
~ r anges. A U Te typ e 0- 10 was selected.
For this transformer , N = 3.875 using Y2
primary to f ull secondary, or N =7.75,
using f ull primar y to full secondary.
Using N = 3.875 we find R o f r om Eq.
(4) : R o =N
X
20000
1'00
_
='(75 ohms.
R o should be measured accurately on
a bridge. This will eliminate the necessity of using a variable adjustment for
R o·
~m'n can now be chosen . A value of
~mi" = 5.0 seemed r easonable after look-
ing over t he characteristics of transistors
pr esently available. Then :
5 .0 = ~m" " =N
o :.:
(1 + RRm"")
(3.875 ) x
(1+ Rm"")
775
Thus, R m ,,, =225 ohms.
A 500-ohm p otentiometer (R 2 in F'ig.
2) , is used to adjust R min to its exact
value.
The r est of the circuit is designed so
that any transistor inserted in the test
instrument will oper a te at approxima tely
6 volts collector voltage and approxima tely 1 ma emitter cun en t. Switch 8 ~
is included so that either P NP or NP N
units can be tested, and switch 8 3 changes
the dial reading f r om " times I " to "times
2." One word of caution: check to see
that the transfor mer is wired with the
same phasing shown in Fig. 2- otherwise
the circuit will not oscillate. To keep t he
instrument as simple and inexp ensive as
p ossible, no detector or meter was in cor p ora ted in the circuit. Any detector ,
such as ear phones, V TVM, or oscilloscope can be used t o detect when oscillation just starts.
W hen taking a r eading, start from a
high dial setting towards the low one.
A r eading should be taken when the oscillations j ust start, n ot when they stop, as
indicated when going f rom a low r eading
to a high one.
Calibration
To calibr ate the ~ tester , an oscillator,
a V TVM (such as a B allatin e Model
300) and two precision r esistors ar e r equired, one of 0.1 megohms and one of
1000 ohms, as in Fig . 3. The audio oscillator is set for 1000 cp s, and its output
at about 10 volts. The ba ttery leads are
shorted and ar e the "gr ound p oint." The
O.l-meg. r esistor is wired between the
collector terminal and the oscillator. Th e
1000-ohm resistor is wired between the
base and emitter terminals. 8 3 should be
in the "Xl" position.
By comparing F ig. 3 to Fig, 1 it will
be noted that:
~ = I" = ~ 7 V OIII =
I b 100,000
A"
0.1 Meg .
1000 cps
10 v. rms
Fig . 3, Circuit used
for calib ration of
th e t ran sis tor
te ster.
1000
ViII
V o"tx100
The dial should n ow be set so that
when the 10-t urn potentiometer is at zer o
resistance, it reads ~miDl i.e. 5.0. Rotate
the dial ten f ull turns to check if it r eads
105.0 i.e. : ~ m i n + 100.0, ( To avoid turning the potentiometer ten t urns every
time, leave it at its maximum r esistance
setti ng and use a short clip lead to short
it out when zero r esistance is r equired
during calibration measurements ). With
R j a t zero ohms (using clip lead) adj ust
R 2 to get :
V;n
100
X
V Ollt
~
= ""'IV
W ith R, a t maximum r esistance see if:
V iII
_
rt
100 x V 011 1 = 100 + IJ""n
" GROUND POINT "A"
DURING CALIBRATION
22
If Ro is the prop er value then the measurements should check. If n ot , R o has t o
be trimmed slightly, leaving R z set, until
(Gontintted on page 53 )
AUDIO
•
JULY, 1958
An Amplifier Using New 6CZS's
NATHAN GROSSMAN ':'
Most experimenters have sufficient equipment in the " surplus" department to
construct this simple amplifier which gives good performance in a small package
T
HE 6C Z5, a new R CA miniature
_ power tube, holds much p romise for
the art of audio power amplification.
This tube is not t o be conf usecl with the
6A Q5, 0 1' the English 6BQ5, both of
which it r esembles in construction and
purpose. It is not interchangeable with
them .
It has the same filament, plate and
streen, and load characteristics as the
6V6, of which the 6A Q5 is the minature
typ e, and costs about the same. However , the other character istics are differ ent and provide a considerable impr ovemen t over the lattel: typ es. Th e
negative bias on th e signal grid and th e
transconductance ar e about 15 p el' cent
gr eater and the power output about 20
p el' cent greater f or a plate voltage of
250. In p ush-pull oper ation the 6CZ5
resembles the 6L6 in that it gener ates a
low p er centage of odd hm'm onics and
can be oper ated as a p en tocle with a
p late voltage of 350. Under this latter
circumstance and with 280 volts on the
screen, a bias of - 23.5 volts on the
signal grid, and a plate-to-plate load
of 7500 ohms, two 6CZ5's are rated by
the manufacturer to deliver 21.5 watts
of audi o power and with only 1 p el' cent
of harmoni c distortion.
This adds up to lower supply r equil'ements, lower distortion, lower all around
cost, and higher power output.
To try out a pail' of 6CZ5's the writer
built an amplifier from p arts in the junk
box including a husky output transf ormer which was manufactured about
20 years ago. To avoid exp ense in obtaining good voltage regulation, the writer
used a large bleeder and worked the
amplifie r half way between the recommended p entode and the lower-platevoltage tetr ode operation. With 325 volts
from plate to cathode, the r esults proved
better than exp ected. The plate voltage
did not vary from minimum to maximum
power output, and the total variation of
the screen voltage was only 3.5 p el' cen t.
F igu Te 1 is a schematic of the amplifier as constructed. If it is desired t o
op er ate the amplifier in accordance with
the manufacturer's sp ecifications-th at
is, at 350 volts fr om plate t o cathodethe 100-ohm r esistor, R 1 1,) in the first filter section of the plate supp ly should be
shorted. It would also be necessary t o
* 2017 E. 21th St., B?'oo7clyn 29, N . Y.
AUDIO
0
JULY, 1958
r ep lace the 5Y3 r ectifier with a 5U4 and
to incr ease the size of the step-down
r esistor R 11 to 1500 ohms. Plate and
scr een voltages under these conditions
will v3.{y somewhat with p ower output .
The amplifier shown in F ig . 1. has
about 22 db of negative feedback. Just
before clipping the amplifier deliver ed
to a r esistive load 13.7 watts at 30 cps,
16 watts at 60 cps, and 17 watts at 400
cp s. A t 400 cps the t otal barmonic di stortion at various outputs measured, in
pel' cent : 1 watt, .08; 4 watts, 0.18; 8
watts, 0. 2; 14 watts 0.23. Listening tests
showed tb at this amplifier can deliver
D. gr eat deal of very clean bass.
To obtain similar results it is necessar y that the output transformer have
a large iron cor e and that the windings
have low d.c. resistance. 'I.'he one used
weighed about 4 Ibs. and had a tota l
primary r esistan ce of 225 ohms. Both
'I.'l'iad S-60A and StancoI' 11.-3801 should
be suitable. F or the ultim ate in hig'h
fidelity either 'I.'l'iad S-146A 01' Stancol'
A-8056 should be employed. The reflected
impedan ce of these transform er s is 6600
ohms, which is close enough to the r equired 7500 ohms to cause only a slight
loss of power output.
'fhe characteristics of the 6CZ5 lend
themselves to Ultra-Lineal' operation,
and f or this either the Triad S-146A 0 1'
the Acrosound TO-310 would be appr op riate. For such oper ation 350 volts
should be applied to the plates. This can
be obtained by omitting the bleeder
circuit (resistors R 10 and R llJ and capacitor G5) .
lE
R12
R7
0.68 Meg.
18,000
T1
• EXACT VA LUE S DEPEND
O N OUTPUT TRANSFORMER
T1 -
PLATE-TO-PLATE IMPEDANC E
6600 to 7500 O HMS. (SEE TEXT)
fig. 1. Schematic of the 6CZ5 amplifier
23
Hearing, the Determining Factor
for High-Fidelity Transmission *
In two parts-Part 1
FROM THE ARCHIVES OF BELL TELEPHONE LABORATORIES
This is perhaps the first authoritative study of the requirements for ideal systems for the
transmission of speech and music. Much of our present-day knowledge and practice
stems from this article , which presents conclusions derived from measurements of
hearing on more than 500,000 people during the World 's Fairs in 1939 and 1940.
HENEVER a sound is made by a
sudden impact of one solid body
upon another, a wave train is set
up in the air which contains components
ranging in frequency from zerO to infinity . As the impact becomes mor e sudden, the higher-freq uency components
carry a greater portion of the total
acoustic energy . An ideal tmnsmission
system f r om a physicist's standpoint
might be defined as one which would
transmit such sounds to a distant point
a nd ther e reproduce a distUl"bance in the
air which is a facsimile of that produced
by the original SOUl"ce. The r equirements
for such a system are very severe and
it i. difficult, if not impossible, to attain
them.
The pUl"pose of transmitting sounds to
a distant place is usually so that persons may hear them. Certainly this is
true of broadcast systems, telephone systems, and sound-picture systems. Under
such conditions the properties of the
hearing mechanism and the characteristics of the listening location, rather
than the properties of the sounds transmi.tted, will very largely determine the
fundamental r equirements of the transllI ission system. This will certainly be
true if we wish to transmit all kinds of
sounds which can be heard. However, if
we are interested in only a limited number of sounds, then the characteristics
of these sounds p lay a greater part in
determining the r equirements for the
transmission system.
During the years 1938-1940 a survey
of the hearing capabilities of p ersons in
a typical population was made by the
Bell Telephone Laboratories. This ' was
W
* Reprinted by permi ssion from B ell System l'elephone l'echnical Monogmph B-
done in connection with the exhibits at
the W orld's Fairs at San Francisco and
New York City, sponsored by the Bell
Telephone companies. At these exhibits
records of the hearing of mor e than one
half million persons wer e analyzed. The
r ecord expr essed the hearin g acuity as
a relative hearing loss 01' gain with respect to an arbitrary refel·en ce. Measmements at the Labomtories on this refel"ence have made it possible to express
these data on an absolute scale and the
r esults have been published by Steinberg, Montgomery, and Gardner.1 F igm'e 1 has been constructed from data
taken f r om this paper. The lower curve
labeled 95 indicates tha t 95 out of 100
persons in a typical gToup cannot hear
pure tones whose frequency and intensity levels lie below this curve. The top
CUl"ve indica te ' tbat 5 out of 100 cannot
hear these tones until they exceed the
1 J. C. Steinberg, H. C. Montgomery, and
M . B. Ga rdner, "Results of the Worlcl's
Fair hearing tests," B ell Sys. l'ech. Jo u?".,
vol. 19, pp. 533-562; October, 1940.
130
120
100
80
Fig. 1. Contours
of hearing loss
and room noise.
60
24
2 D. F . Seacord, "Room noise at subscriber's telephone locations," J. .dcous. Soc.
41Jt., \' 0 1. 12, pp. 183-187; July, 1940.
LfEE , It~ G~ANl> jURTlN'G lEVEL
\.
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1\ \:
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20
iu
2
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>-
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i
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1351. Originally presented at the Broadcast
Engineering Conference, Columbus, Ohio,
in F ebruary, 1941.
** Bell l'elephone Labomtories.
intensity levels indicated by this CUl"ve.
The middle CUl"ve indica tes the levels
wher e one half the group can hear and
the other half cannot heal'. The dashed
portions of the CUl"ves indicate r egions
where no measurements have been made.
Peeling and hUl"ting levels lie somewhere above 120 decibels as indicated by
the field of dots a t the top of the chart.
Oul" exp erience with r eproduced music
has taught us that it is undesira ble and
probably unsafe to r epr oduce for a general audience sounds that have greater
intensity levels than 120 decibels.
If the listener is in a quiet place, these
eUl'Ves set the limits for the ideal transmission system. This ideal of no noise is
seldom if ever realized by listeners.
Measurements of r oom noise have been
made by the Bell Telephone Laboratories
:md from these measurements the averuge noise spectrum can be deduced. In a
p aper by Seacord 2 it was found that 43
OM?
. ..
. ..
IN
CYC LES
PER
..
10000
•
JULY, 1958
1.0000?
'0000
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OF
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AUDIO
•
JULY, 1958
25
decibels was the average sound level in
r esidences not having radios p laying .
The standard deviation of levels in differ ent r esidences from this figm'e was
5.5 decibels. The distribution about this
average value indicated that about one
half the residences have noise levels between 39 and 47 decibels, and 90 p er
cent ar e in the r ange between 33 and 52
decibels.
Roth 3 found that the form of the noise
spectrum was about the same f or all
types of rooms. Using his r elation, the
spectrum for the average room noise
having a total level of 43 decibels is
that shown in F ig. 2, lower curve. The
ordinates give the spectrum level. This
is obtained as follows. The intensity I in
a band of f r equency width W is measured. Then the ordinates yar e given by
y = 10 log 1/W1o
where 10 is the r ef er en ce level of 10- 1G
watt p er square centimeter. It has been
shown'1 that the masking level could be
obtained dll.'ectly f rom the sp ectrum
level. Using this relation, the curve
shown in F ig. 2, labeled }\r[aSK ING L EVEL,
was obtained, This curve then gives the
level of pure tones which can just be perceived in the presence of average room
noise. This masking cur ve is the one
which is shown in Fig . 1 as a crosshatched band, It shows the range of the
masking levels for about 90 p er cent of
the r esidences in a typical group , The
dashed curve gives the aver age. If we
wish to include only the middle 50 p er
cent of the residences, the top part of
this masking-level band would be lowered about 5 decibels.
Transmission Limits
F igw 'e 1 then enables us to set several limits for an ideal transmission system. If the noise emitted by the radio
set in a typical r esidence is not to be
heard, its level should be below the
average threshold of hearing in the
room. For a n aver age room this is seen
to be determined by the hearing mecha3 D. F . Hoth, "Room noise spectra at subscribers' telephone lo<:utions," J. Aoo~ts.
S oo. A m ., vol. 12, pp. 499-504; April, 1941.
4 H. Fletcher and W. A. Munson, "Relation between loudness and masking," J .
Ao01ts. S oo. A m ., vol. 9, pp. 1- 10 ; July,
1937.
.............
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1\
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0
2.
'00
,
..
--
I
II
~ ~ ~ ~~
'0000
'000
20<
FREQUENC Y IN CYCLES PER SECOND
lI ism f r om low fr equen cies to 200 cps,
and by the 1'00111 noise f rom 200 to 6000
cps, and again by the hearlllg mechanism above 6000 cps. For example, the
fundamental of a 60-cp s hum should be
kept below a 57-decibel level, whereas
any components of this hum around
1000 cps should be kept below 25-decibel
intensity level for the aver age room. It
is seen that for the 5 p er cent of the
rooms which are quietest the limit is set
entirely by the hearing-acuity curve.
From F igu?'e lone can also set the frequency limits for an average listener if
all sounds that can be heard are to be
used ill the broadcast. This r ange is from
20 to 15,000 cps for the highest possible
levels, and for any lower levels this frequency range is smaller, as indicated.
F igw'e 1 also gives the.maximum levels
such an ideal system might be called
upon to transmit. This maximum level
is taken as 120 decibels and the same for
all f r equencies. There is an uncertainty
of about 10 decibels concernlllg the level
tha t can be toler ated by the aver age
ear. Our exp erience with reproduced
sounds near this level indicates that it
is ver y unlikely that higher levels will
be used even though levels somewhat
higher than 120 decibels may be tolerated by an average listener without producing p ermanent injury to the ear. It is
probable that there will seldom if ever
he a demand for such high intensity
LEVEL
--I-
~ ~ ~I%
'/,o~
~~
~ ~ ~ ~t/
Fig . 2. Ave rage
room noise spectrum .
t-.
'000
FREQUENCY IN CYCLES PER SECON D
26
1\
Fig. 3 . Hearing
limits
for
pure
tones-ty pical lis ten e r
in
typical
residential
room
noi se.
L:C!JJ-
SPECTRVi:i ILEVEL
- 202.
1\
.. .
0000
levels in a home, but if we are thinking
in terms of an ideal which is set by
human-hearing capabilities the upper
limit must be taken a t least as high as
120 decibels. The power P for producing
the maximum level of 120 decibels varies
f rom 3 wa tts f or a typical r esidential
room to 400 wa tts for a concert hall such
as the A cademy of Music in Philadelphia. It may be obtained from the f orlnula
P =0.00012 V / T watts
wher e V is the volume of the room in
cubic f eet and T is the rever beration
time in seconds.
If we utilize the entir e intensity level
range f rom the average threshold in a
r oom having average noise to 120 decibels level, it will be seen that from 2000
to 6000 cp s this r ange is a pproxilnately
100 decibels. From 500 to 2000 cp s it is
about 5 decibels less than this figure,
while for 100 cp s the r ange is only 75
decibels. It should be emphasized that
these figm es r efer to the level r ange of
single-f r equen cy tones. When talking
about progr am mater ial wher e complex
sounds ar e used which ar e rapidly var ylllg ill intensity and frequ ency, the ma tter of measuring illtensity level range
is not simple as will be evident f rom
la ter discussions.
A summary of these conclusions is
g-iven by the cm ves in F ig. 3, which give
the limits ilnposed by the hearing of an
aver age p erson in a room having average room noise. I n using this cmve it
l1Just be r emember ed tha t the lower limiting curve may be anywher e ill the
shaded ar ea, depending upon the room
noise condition. This shaded area covers
90 p er cent of noise conditions in r esiden ces. For an aver age business office
t.b e lower curve will be r aised about 15
decibels, and f or a factory location the
lower curve will be raised nearly 35 decibels, leaving a range of only 60 decibels
even if the highest levels that can be tolerated by the ear ar e used.
(Continued on lJage 49)
AUDIO
•
JULY, 1958
uutr
Now - at last - a high quality tuner, and from McIntosh! Two long, arduous
years of development and experimentation has resulted in several outstanding
and new features to bring you unprecedented performance. Drift free without
A. F . C. yet incorporates, the strongest, and only distortion free, A. F. C. (automatic tuning) - no alignment problems, mechanically captive transformers prevent mis-alignment from vibration, transportation, etc.; (for the first time, tube
changes do not require re-alignment - Ultra-Sonic muting (absolute quiet
between stations) - flat, distortion free, frequency response (lowest distortion
for equivalent Signal input) and many more.
Mcintosh Laboratories, Inc.
2 Chambers Street, Dept. AE-7-58
Binghamton, New York
Please send me a full color photograph of the
Mcintosh MR-55 A.M.·F.M. tuner . .. The tuner that
"keeps the promise of F.M."
NAME _______ ___ __ ________ ______________ _
ADDRESS . ______ ____ __ ___ _____ ___________ _
CITY ______ ____ __ ___ __ __ ______ ZONE - -- - STATE . ____ __ ______ ___ ~ ---- - ------ ---- ---
AUDIO
•
JULY, 1958
27
Equipment Review
Tandberg Model 3 Stereo Tape Recorder-Lektrostat
Record Cleaner-Heathkit EA-2 12-watt Amplifier
TANDBERG STEREO
TAPE MACHINE
T
and thereby f eeding the outputs from both
tracks to the siugle speaker.
The T a ndberg' s power amplifier s have
single-ended outputs, each using one EL-84,
but a re able to put out enough power at
r eason a bly low distortion to drive an efficient speaker to a very substantial leveL
he T andberg Model 3 stereo tape recorder (Fig s_ 1, 2, 3) , a product of
Norway, is desigued to play in-line
stereo tapes and to r ecord monaurally_ It
is a small, versatile, high-quality 32-pound On a T andberg that he used for sever a l
(with case ) package crammed with fea. . weeks, th e writer found that 1M distortion
tures r eflecting t he designers' efforts to ·_· of each ampliflei: measured b elow 2 per
anticipate the stereofan's public needs,
Cf:nt at 1 watt output (equivalent sine wave
whether for a limited cost or money-no- power ) , which was enough to drive his
object inst allation .
speakers well above the desired leveL If t he
With this machine, a reel of stereo tape, machine is used to supply signal voltages
and just one speaker , stereo can immedito external a mplifiers, with the g ain con trol
ately be brought into the hom e, at least on
set betwee n positions 2 and 3 it can supply
a modest b asis, for t he T a ndberg already
0.5 ,' olt on each chann el-ample fo r any
contains two power amplifieTs and a
control a mplifier- a t about 0.5 per cent 1M,
speaker, a 51/2 " x 8" nnit. Thus the wonld-be which is consistent with high fidelity perster eofan can get off the ground withont formance; t his data is also based on the
writer's measurements.
having to wait nntil he acqnires a second
If it is desired to playa monaura l tape,
chain of high fid elity compon ents-control
amplifi eT, power amplifier, and speaker.
one ca n f eed the monaural signal into both
Eventu a lly, depending np on his sights, he
amplifi er s by tnrning th e mon a ural-ster eo
may wi sh to use a better a mplifi er a nd
switch to t he monaural position. This conbette r· spea l<er in place of those in the
nects both amplifiers to the npper track
Taudberg. In the interim , however, the
signal a nd prevents playing both tracks at
latter enable him t.o enjoy ster eo.
once, which would resnlt in garbled sound ,
The Tandberg's intern al speake r can be particula rly since one of the track s would
connected either to Hs cha nnel l a mplifi er
be played backwa rds.
(upper track; left speaker ) or to its cha nAll or most stereo tapes a re now renel2 amplifier (lower t r ack; right speaker )
corded with N ARTB equa lization , whereby flicking t he monitor spea l( er switch re- fO J·e it is important that the play back maspectively to left or r ight. In mid-position
chine in corpor a te NARTB playback equali{If th e switch, th e speake r is disconnected
zation . T his th e Tan dberg does, and qnite
a ltogether .
accUl'ately. On th e machi ne used by the
F ig1t1"e 3 shows the output jack a rrange- writer, equ alization r emained within 1.5 db
men t, intended for banana plu gs, wh ich of th e NARTB standard over vir t ually t he
may be nsed to feed a signal eith er directly entire audio range. There is a strong tempto extern al speaker s or to th e inputs of cont~ tion not to maintain f ull bass boost at
trol Or power a mplifiers. Should th e liste ner 1he ,' ery low end inasm uch as this accentu ates th e problem of hum. However, the
wish to combin e both ster eo chann els into a
single speaker, he can do so by taking the Tandberg does not succumb to th is tempontput from jacks 2 an d 4, thus p utting the tation and maintains NARTB bass boost,
two outpnt transformel· secondaries in series within 1.5 db, down to at least 30 cps. The
Fig . 3 . Rear pan el of recorder indicates
line voltage to which set, and provid e s
for the outputs and the high-level input_
Small compa rtment at right holds po wer
card.
r ecord-play back response (monaural ) of
the Tandbel·g is a lso excellent, bei ng fla t
within 1 db between 50 and 10,000 cps,
and only 2 elb clown a t 15 kc and 3 db at
20 cps.
There a re ma ny feat ures of inte rest f rom
the viewpoint of designing a quality tape
machine and f rom th e opm·ating viewpoint.
The mot or has a one·pound, la rg e diameter,
dynamica lly ba la nced flywh eel, which helps
acco unt for the exceptionall y good wow a nd
flutter chamcteristics of the T andbe rg, less
than 0.1 p e r cent a t 7.5 ips. For minimum
hnm , the heate rs of the first tube of each
a mplifi er a r e d.c. operated, a nd t he tnbe is
shielded by mu-m etal; the entire amplifier
is scr eened by metal foi l. Th e ma gic-eye
J·eco rd level indicator is damped so that the
eye may follow its peak indications. The inlill e head achi eves a cross-talk ratio of better t.han 60 db by means of a nlll-met al
shield between it s tw'o sections; this is important when a dual-track mon a ural tape is
played, so tha t th e signal picked up by t he
lowe r section of the head is not co upled to
the upper sectio n and t hereby heard in
pl aybac k. 'l'he ga ps of each section a re sufficiently co-linear t hat the hea d may be used
to play fu ll-track r ecordings without an ap parent time difference between the signals
from each section.
Wh en t he tap e is rewonn d or wound ill
th e fo rwa rd direction, th e tape is lifted
away f rom the heads to p revent head wear
due to abr as ive action of the t ap e coating .
No p ress ure pad is requil·ed to maintain
finn contact between the tape and in-line
head-good cont act is very important in
Fig . 1 {left). Panel view of Tandberg Model 3 Stereo Tape Recorder. Fig . 2 (right). Underside view of Tandberg recorder . Section at right is " S" channel in which the output tub e serves as the erase-bias oscillator when used as a monaural recorder.
28
AUDIO
•
JULY, 1958
This
is where
the l11usic
begins
*New Transcription-Type Tone Arm Makes Collaro
World's First True High Fidelity Changer
When you ~ e1ect your high fid elity ~y~tem-an amplifier with
low distortion and low noise level , a speaker capable of reproducing the entire audible range-you want to make certain you
pick the ri ght record player. Because that's where the music
begins_ That's why today's fine high fidelity systems require the
all new Collaro- the turntable t hat changes records-featuring
the revolutionary transcription-type tone arm_
The new arm is one-pIece, counter-balanced and will take any
standard cartridge_ Resonances are below the audible level.
Between the top and bottom of a stack of records there's a
difference of less than 1 gram in the tracking weight as compared with 4 to 8 grams on conventional changers. This insures
better performance for your precious records and longer life
for your expensive styli.
It's worth noting that Collaro quality is so well recognized that
leading American manufacturers of fine console units incorpora te Collaro into their instruments in order to achieve the best
possible performance in a record player.
In additioll to the transcription-type arm, the Collaro COlltinental features :
Four speeds, manual switch that permits playing single record
or portion of a record ; jam proof mechanism, hold the arm in
mid-cvcle and it won't jam ; automatic intermix, plays 7", 10"
or 12" records in any order; automatic shut-off after last record
has been played; wow and flutter specifications, ~ (0.25%)
RMS at 33% RPM, superior to any changer in the world;
muting switch and pop filter to eliminate extraneous noises;
extra heavy duty 4-pole induction motor; heavy rim-weighted,
balanced turntable for fly wheel action; removable heavy rubber
turntable mat; pre-wiring for easy installation; attractive two
tone color scheme to fit any decor; factory custom-testing for
wow, flutter, stylus pressure and correct set-down position.
Reflecting their custom English craftsmanship Collaro changers
are tropicalized to operate under adverse weather and humidity
conditions. The base, in blond or mahogany, is optional at
slightly extra cost and the Collaro mounts easily and quickly
on a pre-cut mounting board or base.
When you buy your Collaro, you're buying professional quality
equipment at a record changer price. Collaro prices start at
$37.50. The Continental, featured above, is $46.50. (Prices are
slightly higher west of the Mississippi.)
FREE : Colorful new catalog. containing guide 00
building record library plus complete ColIsro line ..
WRITE TO DEPT. A-7C.
ROCKBAR CORPORATION
'.
MAMARONECK, N. Y.
Rockbar is the American sales representative for Collaro Ltd. and other fine companies.
AUDIO
•
JULY, 1958
29
preserying high-hequency r espon se-and
the absence of a p a d r educes flutter and
prolongs head life. Tape tension when the
machine i s mnning is kept to a low 10
g rams which ser ves to minimize wear of
heads,' tape guides, and capstan. Starting
and stopping tensions a re respecti vely
about 40 and 120 grams, which means that
the very thin "half-mil" tape, which aff ords
twice t he playing t ime of standard tape on
a given size reel, can be handled without
da nger of breakage or stretching.
For t he purpose of easily spotting a desired passage, the T andberg incorporates
:t program counter with clock-type dial and
two hands. The machine can be used for
public address purposes by putting th e
mode selector switch in the lowest position;
the monitor sp eaker or an ext ernal speaker
or both can then be utilized. A microphone
mted as h aving r esponse to 13,000 cps
within 3 db is suppliecl.
LEKTROSTAT RECORD CLEANER
Fig. 5 . He athkit EA-2 amplifier "sounds as good as it measures" and looks as goo d
as it sounds.
Since the appearance of vinylite microgroove records, their user s have had to cont end with a serious problem of dust (and
other forms of dirt) . As du st gathers on
t he record, noise and distortion and abr asion increase. With t he low tracking pressn r es now prevalent, and becoming ever
l ower, the stylus can accumulate enough
(lust to lift it virtually from the groove.
Those who like to use changers find it fut ile to load on a la rge stack of micr ogroove
r ecords unless some dust-combatting device
is employed, for otherwise t he stylus be·
comes illsuffera bly clogged after only a
r ecord or two.
Hence there h as been a r eady m arket
for recor d cleaning agents, some having
anti·static properties, some det ergent pl"Operties, and some both. A newcomer to this
field, the L ektrostat Record Cleaning kit
(Fig. 4), contains a fluid with both characteristics and claimed to b e non-gumming.
Much of its effectiveness, however, owes to
the special groove-cleaning applicator that
is part of the kit. The writer has u sed
Lektrosta t on his r ecords and found it ver y
effective.
The applica tor is fla t and round a nd has
a spouge rubber core snrrounded by a vel·
vet syn thetic material with a pile of soft
bristles. The fluid is squirted onto the
record a nd distributed by a rotary motion
of t he applicator , following the g rooves.
In fact, it i s difficult not to follow the
grooves, as the nser soon finds out, for he
can feel the bristles slide into them. Th e
applicator not only spreads th e fluid, but,
equally important, lifts the dust and grinJ e
right out of the g roo ·es, leaving no gumming residue. If one wishes to clean an old
r ecord containing a good deal of dirt, it is
advisable first to dislodge most of it by
several wipes with the dry applicator .
The core of t he applicator i s of sponge
rubber so that it will not mat down or become lumpy. Since t he bristles are synthetic, they do not crush dowu, which i s
the t endency for natural fib ers, especially
when wet. The synthetic sheds water, oil,
dirt, a nd so on. It is merely necessary from
time to tim e to wipe or blow off the dirt it
has picked up.
Dexter Chemical Corporation, which
makes L ektrost at, is well known as a m anufacturer of anti-st atic agents and deter gents for the textile and paper indnstries.
Starting with one of the a nti-static fluids
made for these fields, they have tailored it
to have detergent properties as well and,
vel·y inlportant, to be non-gumming. The
solvent employed for the agent is wate r,
which is capable of dissolving the salts and
sugars deposited on the r ecord by h uman
hands. Lektrostat will not evaporate except
a t tempera tures which would harm or destroy the record.
A little bit of t he Lektrostat fl uid goes
a long way-about 5 drops per side. However, an excess dostage does no harm since
the excess i s carried away by the applicator. If th e record is stored in a plastic
bag, the anti-static agent deposited in the
Fig . 4 . le ktrosta t
re cord clean ing kit
incl ude s, an ti -sta ti c
d ete rg e nt, appli ca tor, an d plas ti c
. co n ta.i ner .
30
grooves is claimed to be effectiYe for
months. But paper and cardboar d covers
absorb the fluid, limiting its effectiveness
to weeks or days.
A not unimportant member of the Lektrostat kit is the b ag itself. It is made of
polyethylene fo r streng th and life, so that
the applicator may r eceiYe m a.xim um prot ection against dirt, dust, a nd humidity .
THE HEATHKIT EA-2
AMPLIFIER
At $27.95, the Heathkit EA-2 composite
amplifier-phono preamp, tone controls, and
12-watt power amplifier, on one chassis, as
shown in Fig. 5-is a surprise package. Its
low price might lead the casual obser ver to
dismiss it as something of a toy, perh aps
worthy only of a junior audio system for
the children or the den or the workshop, or
the like. Actually, it is a grown·up perform er , within its 12-watt rating. And it
must be r emembered that the difference between a 12-watt amplifier a nd a 30·watter,
which few sneeze at, is only 4 db, a relatively slight volume difference to t he ear.
The circuit of thc EA-2 is essentially
orthodox an d at the same time up to date.
The magnetic phono preamp consists of a
single stage, followed by losser type equalization. Subsequently there is a stage of
gain for all the inputs, a volume control,
another stage of gain, a nd the tone controls, which are the conventional Sterling
type. The power amplifier section follows
the trend toward use of a pentode input
stage direct-coupled to a triode employed
both as a phase inverter a nd driver for the
output tubes. Pentode and triode a re ill a
single envelope, the now widely used 6ANS.
The phase inver ter is t,.he familiar spli tload type, which some experts hold to be
as good as any. Th e output stage is ultralinear, using the highly-regarded ELS4's.
The EA-2 is easy to assemble a nd took
this reviewer t he equivalent of fo UT eye·
llingS. (The reviewer probably takes a good
deal more t ime than the average, becau e
he checks all r esistors for value, checks
capacitors for value and leakage, checks
continuity of connections by means of an
ohmm eter, donbles back after eyery doze n
steps or so to check his work, and so 011.
On t he other ha nd, the careful appr oach
has paid off in that every one of th e dozen
or more Idts he has built in this mann er
has worked correctly right from the star t.)
Although the chassis is only S-3/ 16" deep
by 12V2 " wide, the layout is uncramped a nel
at no t ime l·equires a surgeon's dexterity.
AUDIO
•
JULY, 1958
· .. yet how
sweet
the sound!
Generate the full excitement of High-Fidelity!
Specify the new RCA- 7027 for your amplifier designs
Stronger and stronger grow the chords, the fervent expression of the artist-yet the
sound is sweet, most pleasing to the listener's ear. The Concert Grand makes stringent
demands upon high-fidelity amplifiers for high power and low distortion. Can your
designs meet these demands? They can if you "design around" the RCA-7027!
RCA-7027 is a glass-octal type beam power tube. Two 7027's in Class AB 1 , push-pull
service with 450 volts on the plate can handle up to 50 watts of audio power with
only 1.5 percent distortion. Structural features contributing to the exceptionally high
plate dissipation (25 watts) of this compact tube are : button-stem construction,
heavy stem leads having high heat conductivity, heavy plate material, radiating fins
on control grid, and double base-pin connections for both control grid and screen grid.
Achieve for your hi-fi designs the advantages of high diSSipation, exceptionally
low distortion, and high power amplification offered by the new RCA-7027. Ask your
RCA Field Representative for further details. For technical data, Wl'ite RCA
Commercial Engineering, Section G-91-DE, Harrison, N. J.
RCA Field Offices
EAST: 744 Broad Street
Newark 2, N. J.
HUmboldt 5-3900
MIDWEST: Suite 1154,
Merchandise Mort Plaza
Chicago 54, Illinois
WHitehall 4-2900
WEST: 6355 E. Washington Blvd.
Los Angeles 22, CalifRAymond 3-8361
. . RADIO CORPORATION OF AMERICA
U
® Electron Tube DiviSion
Harrison, N. J.
z
3.0
~ 2~ f-I 2.0 I-Z
0
;::
g
I
I
HEATHKIT
EA-2
AMPLIFIER
I
/
1.5
Ci 1.0
::;:
0.5
O·
0
-
5
POWER OUTPUT -
'0
WATTS
V
/
15
Fig. 6 . 1M distortion curves for the Heathkit EA-2.
Parts of high quality, as f or example the
use of molded paper capacitors, an ECCS3
as the input tube, ELS4's as the output
tubes, an EZS1 as the rectifier, and power
and output transformers about as husky as
can be accommodated within the amplifier's
dimensions.
Size of the output transformer is reflected in the ability of the EA-2 to turn
out at lea st 12 solid, clean watts at 20 cps,
as viewed on an oscilloscope. At the rated
power of 12 watts, the frequency response
measured was ± 0.5 db between 30 and 10,000 cps, and 1.5 db down at 20 and 15,000
cps, and 3 db down at 20,000 cps. Below 12
watts, frequency response remained essentially the same within tlus range.
High-frequency response was also checked
with the g ain control set at 6 db below
maximum; the resistance of the gain pot
acts as a low-pass filter in conjunction with
the iuput capacitance of the 6C4 (largely
due to Miller effect) , and the low-pass action is greatest when the pot is at mid-resistance. At this setting, response was down
only 0.5 db more at 10,000 cps, 1.2 db more
at 15,000 cps, and 2 db more at 20,000. This
slight a deterioration in treble response is
hardly apt to be noticed. Moreover, it is
quite unlikely that one will be operating
the amplifier with gain as far advanced as
6 db below maximum. With gain 10 db below maximum, there was no a dditional loss
at 10,000 cps, about 0.5 db at 15,000, and
1 db at 20,000. At 20 db down, no additional losses were observed.
To obtain maximum fl atness of response,
with bass and treble control knobs pointing
straight up (12 o'clock ), it was n ecessar y
to rotate the treble control pot about 15°
counter-clockwise (center lug pointing to
a bout 11: 30) . Parts tolerances would account for this. It was not necessary to adjust the mounting of the bass control pot.
Probably the most fascinating thing
about the EA-2 is its low distortion. As
shown in F i g. 6, it does not exceed 1 per
cent 1M until equivalent sine wave power
(the wattmet er reading of two signals
mi."wd in 4: 1 ratio is multiplied by 1.47 to
obtain th e power of a sine wave having the
same p eak ) is above 12 watts. At 10 watts
equivalent sine wave power, 1M was only
0.33 per cent. From 3 watts down, it measured 0.1 per cent or less. The 1M meter
employed for these measurements uses frequencies of 60 and 5000 cps and has a
residual r eading of about .06 per cent. At
10 watts and below, th e p erform ance of
the E A-2 leaves little 'if ' anything to be
desired with respect to distortion. And i t
bears repeating that most audiofans will
not be using more than five wa tts.
An amplifier that measures well with respect to distortion may not sound clean.
Often it will be found tha t such an amplifier displays excessive ringing wb.en square
waves upward of 1000 cps are p assed
through it. The EA-2 exhibited no ring i ng
whatsoevej' on square waves of 1000, 5000,
32
10,000 and 20,000 cps, and even with treble
boost applied.
Still on the subj ect of distol·tion, it was
found that at 1000 cps the EA-2 clipped at
j ust about 15 watts. So one can t hink of
the EA-2 as a 15-watt amplifier since 1M
is just a little over 2 per cent at this point.
Sensitivity of this H eathkit is quite sufficient. It was measured at approxim ately
0.3 volts on high-level inputs and 8.6 mv
on the magnetic phono input for 12 watts
output. Since one can count on approximately 15 to 20 mv on peaks f rom even th e
weakest magnetic cartridges, no problem of
inadequate gain is anticipated on magnetic
phono input. High-level sources generally
turn out f rom 0.5 to 3 volts on peaks, so
there is no problem in this respect either.
In fact , the problem may be too much signal input. For example, some piezoelectric
cartridges deliver a volt or two on peaks,
and some magnetic cartridges put out much
as 100 mv or more. In the case of highlevel sources, the input signal could easily
be cnt by reducing the lower leg of the
voltage divider at the inpnt. The signal of
a high output magnetic cartridge can b e
reduced by replacing the 47,000-ohm load
resistor with an appropriate voltage divider consisting of two resistors having a
total value recommended by the cartridge
manufacturer.
Only RIAA phono equalization is provided; however, this suits virtually all
records presently made· and, with slight adjustment of the tone controls, is adequat e
for records made prior to 1954. B etween 30
and 15,000 cps, eqnalization did not deviate
more th an 1.5 db from the RIAA curve.
The tone controls of the EA·2 provide a
substantial range of boost and cut. Ample
bass boost is pa rticularly welcome since no
loudness compensation is provided for the
Fletcher·Munson effect. At 30 cps, a maximum of 16.5 db boost and 17.5 db cut were
measured. Maximum treble boost measUl'ed
16 db at 15,000 cps, and cut 21.5 db .
Since the EA -2 aims so high, it is not
unfair to talk abont its drawbacks, even
though its price is so low. One drawback
is the provision of only three inputs- tuner,
crystal-phono (suitable for ceramic car tridges as well ) , and magnetic phono. However, a tuner, TV, tape machine, or other
lLigh level source can also be f ed into the
crystal-phono input. The audiofan desiring
mOl'e inputs probably would not find it difficult to replace the existing selector switch
and to mount an additional input jack or
two.
A salient onUssion is an output for f eeding a tape recol·der. But this could be rectifi ed quite easily, if desired. In fact, in constructing his EA· 2, the reviewer p aved the
way for such an addition in the futur e.
Instead of mounting a seven·pin wafer
socket f or V2, a 6C4, he mounted a nine·
pin ceramic socket in the same hole and
employe d half of a 12AU7, which is the
same as a 6C4. The other half of the 12AU7
can eventually be employed as a cathode
follower, requiring only a coupling capa ci·
tor and three resistors to be added to th e
circuit. The cathode follower would be inserted between V2 and V3, and a jack in·
tended f or f eeding a tape I'ecorder would
be connect ed to the output of the new
stage.
In term s of perf ormance, the only criti·
cism t hat can be directed at the EA-2 is
its modest signal-to· noise r atio. On high
level inputs the reviewer measured 60 db
noise and hum below 12 watts output at
1000 cps. On magnetic phono input he measured a 47 db signal to noise ratio. Ratios
a.t least 10 db higheI' would be more in line
with professional performance.
With gain control full dOlVn, slight hum
call be heard witlun a f ew f eet of a speaker
of average efficiency. This originates in the
poweI' amplifier section (V 3, V4, V5 ) and
is likely due to in adequa te filtering of the
B + supply for the output tubes. In a quiet
listening room and when the program
source contains little noise, the hum might
be bothersome to a listener sitting close to
the speaker. W e tried adding a 3D-ohm r e·
sistoI' betwee n t he rectifier catho de and the
B + lead of t he outpnt transformer, bypassing this point to gronnd with a 40 I-lf
electrolyti c capacitor f or the additiona.l
filtering and increased the signal-to-noise
ratio by about 11 db.
But over all, as it stands, th e EA-2 pro·
vides exceptional perform ance at its price,
and in a number of respects excellent perform ance at any price. To t he handy audiophile, it furth ermore offers a ttractive opportunities f or increasing flexibility of performance ; and possibly he may find a way
to rednce hum, if it does turn out to be a
problem in his case.
lE
AUDIO ETC
(f!'Om page 12 )
there were sufficient cro ss-talk between
tracks to b e noticeable. The tracks are interleaved, two each direction, so that each
track has at least one other adj acent to it
that runs in the opposite direction. (I
might be wrong but at this point I gather
this is the case.)
Cross-talk simply m~tst have been reduced to acceptable limits-or RCA is
sticking its neck out. So is Ampex. The
b asic four· track system used by RCA is the
same as that recently announced by Ampex. Maybe you distrust one or the other
of these concerns; I doubt if you will feel
like distrusting both of them on this matter. However-we shall see. If cross-talk is
apparent in the four -track recording and
is obnoxious, then a huge commercial development has been falsely and nUstakenly
launched! As I say, in the demonstrations
I heard no cross t alk at all when the stereo
t ape was played from two of the four
tracks. I must assume that no tricks were
played on us. I doubt if it would be worth
RCA's time to do so, even if it were so inclined.
Cartridge size? The thing is amazingly
compact, considering the full hour of stereo
sound (two hours of monaural home recording ) that it can cont ain. I forgot to
measure the box, but the cartridge itself
is as thin as a cigarette lighter and just
seven inches long, five inches wide. Not unlike one of t hose "fl at 50" metal cigarette
cases in general shape. Its packing box is
like those for present tap es but smaller,
oblong instead of square.
The long side of the cartridge is horizontal in the playing position; the tape
runs along the lower edge, past a series of
five inset slots in the cartridge body. It is
here that the playing and drive mechanisms operate, f rom the machine itself. T o
put the cartridge in place you simply slip
the top edge under a fl ange on the machine and drop the rest down in place.
The slight cr ack b etween the cartridge and
the business part of the machinery that
lies against i t r epresents t he usual "slot"
on the a ver age hom e tape machine-but
here the t ape, reels, and holder all come
out in a piece. Simple.
The cartridge itself is of the utmost
simplicity-the two halves are almost
identical plastic sections that fit together.
The simple spring-loaded brake mech anism
is about all there is ill addi tion, plus the
two hubs, loose in their cut-out holes and
two sheet s of cellophane-like material.
AUDIO
•
JULY, 1958
... and ideal for stereo, some of
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Provides unusu a ll y well balanced reproduction of a ll frequencies. Int egrat ion of direct
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a clean 5-10 watt amplifier is more Lhan adequate.
Use in corner, against wall , even upside down
near th e ceiling. Available as enclosure, fini shed
or unfini shed, for use with an y University 8" or
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COMPANIONETTE 2-WAY SYSTEM
Ideal {or booksh elf u sc or a s an extensio n speaker.
Employs "c1islribulcd pOrl" p h ase inve r sion prin-
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For complete descriptions and specifications Oll
these and other fine Ulliversity speaker systems
alld enclosw'es-and for the complete P·S·E story,
write Desk R-5, University Loudspeakers, Inc.,
80 So, Ke1lSico Ave., White Pia illS, N . Y.
AUDIO
•
JULY, 1958
33
Reel size ? Ah- what a neat trick! Ther e
n ren't any r eel flanges (the cartridge holds
t he roll of t ap e in place) and so the two
tape rolls can b e placed close together. As
one grows larger , the other diminishes,
getting out of the way. This allows a r ela·
t ively large roll of tape in a surprisingly
small space.
It's a brilliant, utterly simple idea, real
Colu mbus·and·the·egg stuff, and it excites
my deepest admiration. I enjoy seeing
things used f or the first time that ar e so
obvious that you can't believe t hey are
tru ly innovations. This is one of them, for
me anyhow. Ther e hasn't been a ny appli·
cation of the idea before now, at least in
the hi·fi field . (I suppose this sort of tape
reeling has been used in plenty of other
a pplications- probably in a Sputnik 0 1'
Explorer or two. )
Ca rtridge drive? Alas, I was so f asci·
nated by the whole gadget that I forgot
to notice how the tape transport actually
worked- except that it starts almost in·
t antly when the cartl'idge is slipped un·
del' the r ear flange and dropped in place.
No fumbling for prongs or levers to fit into
holes-the thing just drops right in; then
the little hnbs begin to turn.
Head contact? The tape, as yo u m ay
have already figured out, is wound in the
uB" fashion, with the coated magnetic
side out instead of in. The heads, obviously, face away from you as you look
at t he machine, towards the back; in stand·
ard machines they face towards you. The
m'ase head i s dead center (operating with
the cartridge in either position, tUl"llover ) .
'1'he r ecord head is at an adjacent slottwo heads f or the automatic reversing models' one on each side of the er ase. The
capstan comes up behind the tape through
another space, as you drop the cartridge
in place. '1'he heads, of course, are do ubl e
stacked, of the new type that operates on
two of th e four tracks, staggered hori·
zontally.
So it goes, as to detail. There's plenty
more- but soon after this appears, you'll
be able to get one for yourself, if yon
ha ven't already. (The cartridges were supposedly i ssued in June, but th e machines
on which they play wer en't due until th e
end of this month, as of publication time.)
Playe'rs a vailable? A slight financial
snag here; RCA's semi-automatic ( hand
turnover) stereo tape r ecorder-player will
sell for just under $300, which ain't hay.
The autom atic (self-reversing ) model will
be aroun d $450 . You can buy the cartridges
cheap but you can't play 'em so cheaply
-now.
However , RCA has given the specs for
the whole system to the industry, in today's usual fashion. There is some r eason
to think that a wide variet y of tape playin g and r ecording equipment for th e new
cart ridge will soon b e on the way. RCA
says it has no plans for a tape deck. But
other companies are suppo sed to be working on that. I exp ect that by f all there will
be a good beginning in thi s direction, assuming that the cartridge looks good to
all of us. It looks good to me, right now.
As of a first inspection, I see no r eason
why the new tape player should be any
more e:-.-pensive than a ronghly compar able
standard machine. The basic mechanism s
fo r the drive are pretty much th e samefast speed each way via pushbuttons, t he
usual start button, plus a track selector
(fo r monaural r ecording on all four tracks
one at a time) that should be no mor~
t han a simple switch. '1'he whole t hing is
~'ea lly extraordinarily simple ; that's why
It appeals to me. It seems to be extraordinarily fo olproof too, in simple and i ngenious ways ; that also appeals to me and
will to yo u.
34
Com pati bility ? RCA has stru ck firm ly
towards a constructive and health y incompatibility. The new cartridge plays on its
ow n special machine, and th at is that.
Ther e really wasn't much nse trying for a
compromise. The heads are differ ent, the
tracks ar e differ ent, the entire geometry
was necessarily different if the system was
to t ake f ull advantage of cartridge oper ation and of f our-track recording. This,
it seems to me, was both inevitable and
r easonable. We have here what is usually
called a clean break, for a new approach.
Ampex, to be snre, i s offering conversions fo r its present home t ape player s
t hat will allow them to play four-track
tape. But these are for st andard r eelingnot cartridge tape. (You can buy an RCA
cartridge and reel the tape out of it onto
a n ordinary reel, then play it on the
Ampex, if I get it straight.) This is my
present information, anyhow, as of our
usual ahead-of-time publication date.
I snppose some ingenious soul will soon
devise a market able two·way machine, to
play both the cartrici!ged tape and t he conventional reels- two-tracked at 71/2 ips and
four -t r acked, inter-leaved, at 3%, ips- but
tJ:ti~ will hardly mak
for true compatibIlIty . It'll be a necessary makeshift, like
t he turnover cartridge and the 45 rpmremovable center spindle.
The editor suggests th at the constru ction
won't be too tough a problem even so. The
cartridge tape is wound coated side ou t,
t he heads play from th e near or lower side
as yon look down 011 the machine, wh er eas
present r ecorders work just oppositely. To
get all the heads on one side, the lower
side, you could (be snggests ) mount yonr
standar d 7" r eels to play with t he feed and
take-up from th e side near est th e center
the reel s turning the opposite directiol:
from at present; this would bring the
coated side down . Look s fUllny but it is
entirely feasible. All the tape heads, newtype and old, would then operate from th e
lower side, to leave the necessary space for
the cartridge. I can imagine the tricky
a rrangement wher eby the cartridged tape
would hit only the heads it requires, while
th e ma nu al t ape would be threaded to CO li'
tact one or more different heads. N ot too
complicated .
'1'her e would have to be a donble drive.
The two spindles for the cartridge would
be close together in the center and r etractable below deck·level for manu al play. The
larger 7" r eels would mount more or less
as now except for the reverse turn. Their
flanges wo uld overlap th e cartridge space
in the middle in order to get t hem as close
together as possible (natch, only one syst Em would be used at a time).
Possible-but with this dual drive and
with extra heads t he home machin es of
tl~is sor t. aren't .going to be too cheap . It
WIll b e mterestmg to see what is forthcoming when the t ape machine makers have
finally had a chance to cat ch th eir breath.
Incompatibility, yo u see, is an essential
part of th is r adically new system and it
might just as well be faced up to for the
time being. A disadvantage-an agony for
many who have standard tapes they want
to play. RCA has had to close its corporate
eyes to t he woes of the good people who
have been buying all those RCA two-track
ste reo tapes, at th e fabu lous high prices,
these last few years. The olu tapes will
be supplied, incidentally, "as long as there's
a demand," says RCA. That probably
~lC::u S not fo r long. Demand, at the price,
IS lIkely to fall off pretty f ast now.
Specifi cati ons ? Th e big missing factor
as o~ the .time I am writing, is the body of
speCIfi catIOns that would give us a concr ete
clue to th e claimed performance of t hi s
ca rtridge tape system. Th e Ampex a n-
noun cement of fo ur-track tap e, somewhat
earlier, also avoided direct specifications.
B ut th e clear implication, from both Ampex and RCA, is that this new fonr-track
slow t ape is fully satisfactory fo r hom
use- at a cost higher than standard r ecords a nd higher than stereo disc. That indicates pretty clearly what we have to
deal with . Nobody is going to b uy a
noticeably inferior sound on tape for mOl'e
than the cost of high quality disc.
The fo ur-track tape has to be good, then.
It must be, or it would not have been
launched in the present form. It sounded
good, as I say, on my first hearing-very
good .
The necessary improvements, moreove r,
were in th e cards, in line with the constant
bettering of tape equipment over t he year
and especially in connection with th e f abulously rapid development of t ap e in the
science fields, in comp uter work, telemeter ing, missiles and a million and one other
industrial uses. Though I'm not exactly
up on the details of all of this, I am very
much of the inlpression that a fou r -track
home tape of hi-fi qu ality, equivalent to
the sound of t he best two-track 7% ips
tape in the past, is just the sort of t hing
we should be getting, about now. I fully
e:-.-pect to find, on closer listening, that the
RCA tape is j ust that. Again- it has to
be. So h as the Ampex t ap e, th e same four track system.
Are the re bug s? Not yet in public-but
you can bet your life tb ere will be. Why
noH Will some people gro an and shake
th eir heads, as each bug appears~ Defi·
nitely-ther e's always a plethora of doom·
prophets around wh en a n ew system tries
its sonic wings. I do hope you can r emember back ten years to the LP and its first
days. If all the prophets of doom that
condemned the LP had been right, we
wonldn't have 20,000 LP records in th e
current LP catalogue.
It looks to me as though there were indeed room for a few bugs in this cartridge
system-but I snspect the major ones have
been pretty much by-passed already. The
early 45 r ecord warped and wouldn't change
on its fancy little changer-but th e car tridge tap e probably won't pull loose from
its hubs at the end of a ruu, nor is the
tape likely to snarl easily. It's well prot ected and the machinery ought to work.
Maybe the tracks, or some of them will
overlap a bit now and then, at first.
Could be. Bnt it'll be corrected. I ' ll bet
you a ha t, too, there h as been a lot of
trouble over eq ualiza tion already, behind
the scenes, and there'll probably be 1110re
with maybe some distortion to set ou;.
hi-fi enthusiasts grumbling. Quite likely.
We had a bit of equalization trouble with
LP, didn't we, not to mention a raft of
m aj or tracking and compliance troubles
now la rgely ironed out. I doubt if it witi
be that bad, this time, with cartridge tape.
Yes, ther e'll probably be a mechanical
crack-up or two, her e and there. A.unt Minnie, my favorite character, will doubtless
manage to manhandle her n ew cart ridge
so that the t ape gets caught in the cr ack
between the two halves of the container
and tears itself to pieces-or something of
equivalent n ature. At least one of those
nice hubs is going to let go its tape at the
end of t he playing, just as the 35-mm
camer.a film cartridge lets go at the end,
once ill a blue mooll. I will r ef use to be
stamp e~led into acute disapproval by these
happelUngs unless t hey point to a definite
and deep-seated difficulty, which isn't likely
to be the case, I'd guess. You'd be wise to
feel the same way.
Competition? That's th e big point. T he
tape cartridge isn't even going to bot her to
(Continued on page 38)
A UDIO
•
JULY, 1958
The 4th AUDIO
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EDWARD TATNALL
Around and About
Prokofiev: Piano Concerto # 3 ; 17 Piano
Pieces. Prokofieff; London Symphony,
Coppola (re cord e d 1932 , 1935 ).
Angel COLH 34
T h is is ODe o E the new An gel series, IIG r eat
Record ings of t h e Cen t u ry ," and i t's a most
interestin g record, faithfu lly resto r ed w i t h ·
out sou nd·tampering of a ny k in d . It revcals
Pro kofieff (my customary spellin g) in hi s
ea rly m id dle age as still
it
w bil"lwi nd, big h -
charge, ball-of-fi r e p ia ni st of tremen dou s
power and steely ruggedness. It's odd that
this side of his character-whi ch appears
m usically in man y earl y works a n d some later
ones-is so contr asted to t h e mo r e fa milia r
aspect, b is sweet, bum a n, wa rm nature, expressed in t h e fa mous ly ricism t h at has en deared him to a w o rld popul ar a u d ie n ce.
He re, after a ll, h e was bar el y ou t of t h e
n oisy Twen t ies, as h e played t h e con ce r to;
his later a n d more Romanticall y in clin ed
m usic was largely a h ead of him, a lways exceptin g t h e ext r aordinary li ttle '''Class ical ''
Symph on y. T he solo p iano works, too , on t h e
r everse, a r e f r om h is early a n d prolific
F r en Ch -infl u en ced pian o period, by turns fie rce
and coy, n ea tl y d isson a n t a nd d ia bolically
cleve r . It is cat-like m u s ic a n d fasc i natin g in
bis 1luen t playi ng.
T h e Concer to offers some poi n ts of technical interest in the recording, too. It is,
fi r st, n fine exam ple of t h e ea rl y pre-close-u p
style of solo mic r oph oning w it h orchestra .
You 'll be su r pri sed to hear Prokofieff so far
away, at a d istance down on the sta~e a lon g
with the orchestra-wh ich sometim es drowns
him out. Th is was, of course, no mor e than
a Ii teral represen tation of the conce r t h a ll
sou nd-bu t we do n 't do ou r reco r d ing that
way any morc nnd we fire r ight, I th i n k.
OU I' close-up so lo tech nique, blowing up t h e
soloist to relati vely huge vol u me, is better
for t h e mus ic itself in terms of t h e unique
recorded m ed ium.
The reco r d is a lso in te resti ng for its typically d ry, dead ish acou stics-stnn dard sound
for the time. T h is was merely the no r mal
effect i n these enrly days of the electrical 78 ;
our h uge reverbe r ations, w h eth er r eal or
artificia l, would h ave seemed mo nstr o usly
exaggerated to the ph onogrnph ears of 1932 .
T h e pu re art of r ecorded sound h as moved
a long way s ince then towards its own in depen dence, f r ee of the concert h a ll , and
th is in spite of t h e fact t h at we still obstin ately in voke t h e con cert h a ll as t h ough
ou r r ecor d ings r eall y sou n ded li ke it! They
don' t , a n d tbey shouldn't.
Gounod: Symphony # 2 .
Bizet: Jeux d'Enfants. Lamoure ux arch .,
Decca DL 9982
Marke vitch .
This is a char mer. I f you've ever r u n in to
the now fa mili ar li ttle Symphon y in C of
* 780
36
G're enwich St., N ew YOl'k; 14, N . Y.
C A N B Y'~
Bizet, written when he was abo u t 18, yo u'll
j u mp for t his hi t h er to u nkn ow n compani on p iece by Gou nod , composed in t h e very same
year, 1855, thou gh Gou nod was older, in h is late
t h irt ies. It's interesting that both Bizet (Carmen) and Gou n od (Fa us t) are famous F r ench
opem composers-th ese sympho nies we r e in
both cases tem po r a r y side-excu rs ions in to a
field of lllu s ic that was highly u n popu lar in
Fm nce at t h e time.
This symphony is Ye ry mu ch in the style
of t h e B izet, an effer vescent F r en ch mixture
of well-chosen German i n fl uen ces-Hndyn-like
iu texture, w ith a li ttle Schnbe r t, a Men delssohnian z ing a n d a strong w hiff of Sch uma nn.
T he first m O" ement, part icula r ly, is clearl y
reminiscent (in a lighth earted way) of t h e
Schum an n "R heni sh " Symphon y of a few
yea rs earli e r- it's in t h e sam e key and hus
t h e sam e t ri ple-ti me syn copations.
Th is is n better developed symph on y t h a n
t h e B izet, t h ou gh j u st as t u neful , nnel it i s n
more importnn t work. The aforemen t ion ed
fi r st m ovem en t is a big piece, first ran k; t h e
rest is of som ewh at lesser calibr e tho ugh fin e
fO I' easy li stenin g. Th e L a moureu x-Ma rkevitch
pe rformance is a marvel of ligh t n ess an d
disc iplin e.
Bizet's l ittle ch ildren 's su ite, w r itten i n
late r yea rs, makes a pleasant L P compan ion
work .
Milhaud : Globetrotter Suite; The J oys of
Li fe (1957). Chambe r O rch. , Milhaud.
Decca DL 9965
It was Saint-Saen s who clai med that he
co m posed m u s ic as easily as a f r uit tree bears
fr ui t; Darius Milhau d, French composer
turned CnIifornian, is snrely the modern edition of old Sai n t-Saens . He is famous f or
t urn in g on t m us ic at t he drop of a hat, fo r
any old pmctical pu r pose. L ike ViIl u-Lo bos,
h e is especia lly interested in popu lar and
student music, to be per formed by "the people"-by them and for them.
These two li ttle chambe r or ch estra s uites
",e l'e com m issioned, for u se by trai ned m u sic
stu dents as workin g mater ial but a lso for
pop ular listening. T h ey fill t h e b ill neatly.
T he style is typicall y good humored, acid
M il ha ud, fu ll of tunefu l li ttle ditties, harmo ni zed with v iolen t dissonan ce yet as
str a igh tfo r wa rd as Yankee Doodle.
Yo u 'll find plen ty of local in fluen ce h e r e,
s u pel'jmposed on th e French M ilh aud- t h e
movies are in ever y page of the m u s ic (th e
sort of mu ic used for filmed sho r ts, t r avelogues, hum or ou s bi ts, a nimations). And t her e
are neat toucbes of Ame ricana, int l' :guing bi ts
of pseu do-Bern stein, snggestions of Coplandno do ubt abo u t i t, M ilh aud is an omuh'orous
l istener and everything he hears comes right
bacl\: ou t again in h i s ow n m usi cal mixtu re.
T he Globetrotter Suite, each mo vemen t a
cou n t ry (but ob-so-d iffe ren t from t h e moodmusic trave lognes in vogue of late) is somewhn t on t h e brassy, twangy side, a sort of
modern yersion of the m usical equ ivalent of
tbe sack and th e trapeze. (Milh a u d neve r
ca n qui te get away fro m the lu r e of t h e
Twenties, when be first became famous.) The
Joys of L ife , hom age to a set of Watteau p ictu r es, is very casually of an 18th cen tu r y
mood, w ith tweaky, twangy little minuets,
pnstora les, Musettes; less b r ass and percussion i n t h is one, a smooth er blend.
I s uspect that t h is r ecord will g r ow on you
su btly, if yo u acquire it. T here's n ot a t hing
s pectacula r in it, bn t t h e intim ate, a l most
con versational tone of t h e in struments, the
modest cIa r i ty of tile son n d and the skill
w it b which it is so good humor edly pu t togeth er are likel y to i n trigue you r ea r. Use it
as backgro und mu sic-yo u'll be b rin ging it
ou t iu the foreground befo r e you know it.
Album de Musique. Su zann e Da nco, sop.,
Epic LC 3442
F. Molina ri-Prade ll i, pf.
A ni ce idea, this, a complete reco r ding of
n private nl bum of l ittle a ri as a n d son gs
copied ou t in 1835 fo r a F r ench lady f rien d
by no ne oth er than the great R ossi ni h i mself .
T he only t r ou ble is t h at, at least as s ung
h ere, t h e li ttle t id bits are pretty dull, in th ~
main. I got bor ed after a bou t t hree of them.
You can't expect a li st of popular tu n es of
1835 to m ake any over whelming a p peal to us
today a n yway; bu t Su zan ne Danco's r el ativel y
hea \Ty and over1lorid singing doesn't help a
bit. Sh e seems to be on e of t h ose w h o do
splend idly i n big pieces, are lost in the little
on es. S h e works h ard, bu t these sound mostly
very tired. Maybe t h at's the way she fel t
nbo u t them.
Fra nck: Violin Sonata. Debussy: Violin
Sonata. Ravel: Piece en Forme de Hab a ne ra ; Fa u re : Be rceuse. Da vi d Nad ien,
v I. , Da vi d Han coc k, pf.
Monitor MC 2017
If you' ll loOk closel y, you may be surp ri sed . T he p ian ist in this recording is a
good ill us tration of the model r ecord ing engin eer of t h e 'f u ture--fol' h e's the David HanCoCk w h o is a lso well known a s o ne of the
best engineers in t he recording bus in ess . T hi s
is hi s t ri ple-threat deal- he a lso w ri tes th e
printed notes on tbe back of th e album. He
started as a p ianist (Juill ard) und now is
back at hi s old t ri cks, officia lly.
T he performa nce of t h e F rench m usic isn't
perfect, but it h as w hat plenty of recordin gs
do not have- exci temen t, e:nnestness, and
inten Sity of expr ess ion. I found i t thoro ughly
enjoyable, tho ug h both F ranck and Deb ussy
can take mO r e po li sh, a mo r e s uave exter ior
over t h e i nner t Ul'moil. T h e r ecord in g itself,
n eedl ess to say, is excellen t . The engineer:
Da\' id Ha ncock. He a lso cut t h e LP master.
St rauss: Die Frau ohne Schotten (191 9 ).
So lois ts, Chor us, arch. t he Vie nna State
Ope ra , Bo hm .
London XLLA 46 (5)
I keep postponing these eno r mous a n d
compelli ng opera a l bums for a s uitabl y leisurely even ing; they aren't made for sampling
n or for any sort of qu ickie review, but that's
AUDI O
•
JULY, 1958
what is ill o rd er at t h e mo me n t, perforce.
I've wa ited too long a lready.
This is a str a nge, wild oper a, co min g soo n
afte r t he f amiliar earl y S t rau ss ope rasSa lome, E lektra, Rosenka va lier- btl t onl y t he
fir st of a long st ring that con tinu ed in to tb e
late 'l'birties . 'l'h e thenlc is n so r t of pagan
legenu , f ull of magic, symbolism , and n ot a
li ttle b orror, d eadly ser ions; it mainly concern s a spirit woman who beco m es mor ta l ,
wedded to a wild hunter-l<in g; s he is with ou t
,1 s ba dow a nd mu st at all costs regain on e.
The re is an ela borate plot to acquire tb e
sb adow of a lowly p easa n t womu n . . . th e
tale and i ts sy mboli s m is too complex to go
in to, but the m u sic is powe r full y sweeping,
a nd beautifully perfo rm ed h e r e, e ven if it is
dreadfully long.
H you'll gear yo urself to Wagn er ian proportions, settle d own wi t h the li bretto and
fo ll ow the opera closely , yo u ' ll be h eavil y
r ewa rded for yo ur pain s. It's a big, pote n t
late-Ge rm an oper a. Chief solos : Goltz, Ryanel< ,
Hongen , Schoeller, H opf-a top cast, throughout.
Elisabeth Schumann-Lieder by Hugo
Wolf, Richard Strauss. (Re co rded 19271946).
Angel COLH 102
Another of the "G reat Recordings of the
Century" Angels, and th is qualifies in a number of ways. If YOU have any yen at a ll for
lovely s in g ing of Ge rman so ng, ~you ' ll be
thrilled by this g reat la dy, s ing ing mos tly back
in be r prim e--t·b ough s h e did n ot fade nor
g r ow coarse and in accu ra te in b e l.' la ter years.
Th e voj ce is exquisitely hi g h a nd brilliant,
the expression is of a so rt that i n ow just
plain outdated; nobody can do it todaynobody cou ld get away with it, with t h e
slides a nd s woops, the ch est to n es. But h ere,
in the perspective of r eco rd ed hi sto r y, i t is
bea utiful.
'1' wo things a r e r emarkabl e in t h e r eco nl ings tbemselves. Tb e re is re lat ively s lig bt
improvem en t in tone quali ty over t b e lon g
stretch of 78-rpm recording, ri gh t up througb
tbe end of World War II (th e last discs
made, n o doub t, on leftover pre -war equipment, react ivated). But one recording, mad e
in the s umm er of 1935, is about as fine a
job of vo ice r ecording as I b ope to b ear, quite
disto rtion less and with a s urpris ingly wide
tonal range, plenty to brin g out a ll th e sibi lants of tbe speec h. 'l'h e late r r eco rd s- II
years late r-really aren't quite a s good.
Irmgard Seefried-Goethe Songs. Erik
Decca DL 9974
We rba, pf.
Irmgard Seefried sings Schumann : Frauenliebe und Leben; Mozart: Nine Songs.
Erik Werba, pf.
Decca DL 9971
Irmga rd Seefried's exqui s itely bigh sol)ran o voice is becoming one of t h e most r espected and express ive fo r Ge rman li ede r
s inging today. She h as a fa bul ou s sen se of
musical pi tc h a nd for shades or h a rmon.\'s be Sings "true" to an a s toni shing d eg ree
a nd i t is a pleasure to l isten to b el' fo r t ha t
r easo n a lon e. She is also a m a rvelou s s ing in g
actoI', expressing tbrough s peech t he long
tradition of emotional exc item e nt t b at runs
t h rough a ll German son g.
Seefri ed 's voice h as the same high range
as t hat of E li zabeth Schum a nn , who se prim e
was a r ound 1920, a nd it is in te rest ing to
compare them directly. Schumann is the la rge r
dramatist, t he bigger power. But Seef ri ed ha s
developed h e r own modem way of prescn tation , minu s tile now uns u i tnbl e s lides a nd
swoo ps of tone, making u se of t h e close-up,
intim ate quali ty that has com e to u s with t h e
mi crophone- j us t as today's orators tend to
speak in lighter ton es in s tead o f orating a t
t h e top of their voices, a s of old.
'l'h ese are bo th s up e rb r eco rd s. Seefri ed 's
Mozart is ou ts tandingly beau tif ul- h er light,
accurate, tr ue voi ce is ideal for h im. Bli t ,
su r pisi ngl y, s he a lso sin gs Sch umann 's so n gs
about a woman's love and life wi t h a poig na nt truthfulness of exp reSS ion ra re today.
And a s fo r W olf , witb hi s ext r e me ly tr icky
and difficult barm onic chan ges in almost
eve ry meaSllre of his songs, t here is no one
today who unders tands t h em a nd s in gs them
bette r. Child' s play, for tbis intelligen t voice,
though many a Singe r flound e r s high and dry
AUDIO
•
JULY, 1958
Ro bert Bel l, assembly fore man at A R
A
stethoscope is used in the production te sting of every Acoustic Research
speaker system, to detect possible air leaks in the cabinet. The speaker
is driven by a twenty-cycle signal , and if th ere are any leaks a characteristic
rushing sound can be picke d up at the trouble spot.
Thi s test procedure is necessa ry because th e sealed-in air of an
acoustic suspension encl osure is a basic working element of the speaker
system. In conventional speakers the cone works agai nst th e springy
stiffness of its mec hanica l suspensions; in AR speakers thi s stiffness is
missi ng, and the cone works instead aga inst th e springi ness of the enclosed
air-cu shi on. Like th e new air-suspension cars, the speaker literally rides on air.
The patented AR system req uires a small cabinet, so th at the enclosed air
will be springy enough. An d s,ince th e ai r-c shion does not bind...of. r ae its
elasti c li mit as ·do mechanica l springs, the AR-.1 has crea ted e I inaustry
standards in the lOW-distorti on reprod . ction of music . The fbook~he.lf"
size of AR enclosures is associated witli a 'Kbs olute ~adva nce ra ttler tuanl •
a compwmise in speaRer bas? performanc: . "
AR speakers have been adopted as reference stantlards, as test instruments
for acoustica l laboratori es, and as monitors in recording and broadcast studios.
T .e'ir most import~ t appli cation, _however, has lieen in the natural
reprodliction of music for-the home.
The AR-1 and AR-2, two-way speaker systems complete with enclosures,
are $185 and $96 respectively in either mahogany or birch. Walnut or cherry
is slightly higher and unfinished fir is slightly lower in price.
Literature is availabl e on request.
ACOUSTI C RESEARCH, INC.
24 Thorndike St., Cambridge 41,
Mass,
37
when Wolf pulls his ligh tn in g-fast jumps of
key!
The Goethe so ngs, to texts by the Germ a n
poet and novelist, a re by illu strious com posers all- Mozart, Beethoven, Schubert,
\,\roIf, Schum an n. A far cr y from the dreary
collections of songs to Shakespeare that we
occas ionally hear ; Sh a kespea re has had notably bad lu ck w ith his musical coll aborators.
Schumann : Man f red (complete). Acto rs,
B. B.C.
Cho rus,
Royal
Philha rmonic,
Beecham .
Columb ia M2L 245 (2)
A strange dramatic piece, this, an d hi g h l y
in teresting too. The text is taken from th e
long poem by Byron, of the sa me nam e
(Schumanu, I suppose, set it in German; it
is here used in its orig inal E n glish form) .
Th e work is cast fo r :t g rou p of speaki ng
actors a nd a background chor us w ith grou ps
of solos. The actors speak aga in st alm ost
continu ous m usic for orcbestra- an earl y exa mple of the now-comm on device of baCkgr ound mu s ic for dramatic spoken texts,
though here, of course, with no microphone
to lend its powerful aid. (The re was a good
deal of such drama in th e earl y 19th cent u ry, including, for exam ple, Beethoven 's
"Egmont" an d a number of spoken passages
against m u sic in bis opera "Fidelio, ")
The ever-present a nd indefinable 1na.l(,is e o f
Manfred, w ho is to r t ured by consu min g guilt
and yet can n ot di e, t h ough h e in vo k es all
sorts of dreadful magic spirits to absol ve
him in vain , is one of those typical early
Romantic exp ressions t ha t a re so familiar to
\13 i n variou s musi ca l dramas. In Berlioz, t h e
doleful poet who dreams lurid dreams in the
"Fantastic Symphony" ; the invocation of
dreadful spiri ts a nd t he casting of t h e magic
bullets in Vireber's " Der Freischii tz": the
etern a lly dismal fee lings of Sc hube r t's re's tless
lo ve rs an d wand erer s in his beau tiful songs
- these vaporous a nd ill-defi ned ou tpo urings
of disembodied gri ef are the essence of ea rl y
Romanticism. The fogginess of th em, th e
u tterly in su bs t a n tial "motivatioll ," grief for
g rief's sake, is the g reat preoccupa tion , a lon g
with t h e magic and t he occult invok in gs.
So i t is in "Manfred." In coIcl Engli sh
print, the Byron poetry i s all but unreada ble
for most of us. But when it is set to a mu sical drama like t hi s, it suddenly comes to life
- though the "plot" is as meaningless as ever
in litera l te nn s. Oddly, we are able to sense,
through music, what is hopelessly unin telligible to us i n n on-m usical for m. It's th e sa me
with many an opera with its preposterous
story!
The speakin g voices are excellent here, with
just t h e right amou n t of old fas hi oned oratory, not a bit overdone nor a n t iclim atic.
The Schum a nn overture is fam iliar a lready;
the rest, t he constant background mu sic, is
tantalizingly fragmentary, ve ry lovely but a ll
but inaudible. Too much mike technique, makin g t h e speaking voices louder than Schumann had envi sioned, I wouIcl say.
Americlan Anthology, Vol. 1. K. Brock,
tenor, Jam e s Pe a se , bar., Conco rd Philharmon iam Ko rn.
Conco rd 3007
Just caugh t up with t h is one, issued las t
fall. It's a new hi story of American music
in the actual sound, and qui te faSC inat ing.
There h asn 't been anything lik e it since the
famons old 78-rpm album by the EastmanRocheste r Symphony with H a n son , pre-war,
t ha t pa rad ed out some of th ese same doughty
Ameri can musical warr iors.
The album star ts rathe r uninterestingly
with Fra nc is Hopkinson and a typically
yankee 18th century toast to Washington
So r t of co rn. Then it pl unges in to American
mu si cn l
Romanticism and we!r e off with
a
roar and a sob. A Death Son g fo r an Indian
ch ief by Gra m p recedes a rea ll y remarkably
effective large-scale symphonic overture by
our pion ee r symph oni C co m poser, W illiam
Henry F r y, whose na me has been hea rd mo re
tha n his music. It pull s ou t a ll the stops on
t he subj ect of Macbeth .
Th e n comes a rare or chestral wo rk by th e
excellent Loui s Gottschalk, an overture by
Pain e, whose nam e is still painfully attached
to Harvard's mu s ic departm en t buildin gPa ill e Hall. MacDowell, Ch adwick, and Yale's
Horat io Parke r troo p on to th e scene and
Romanticism turns towards a lu st il y American impress ion ism, with GrilIes a nd Hadley
- th e latte r a dead beat fo r Dukas and t h e
Sor cerer's Apprentice.
No doubt the Concord Philharmon ia is a
trade name fo r a E uropean orch estra, proba bl y t h e Hamburg P hilh ar monia; a las, ~'-\.. m e r ­
ican orchestras cost too mu ch for til is kind
of r ecord in g. But Richa r d Korn is a good
conductor a nd the Germ a ns (?) so und quite
American, especially sin ce most of th e mu s ic
is wholeh earted ly Germanic in style, as was
everything in Nin e teen th Cen t tl r y Ameri ca!
A fine album , and there's evidently more to
come.
Fi rst International Congress of Organists,
London 1957. Six volume s. (Vo ls. 1 & 2
Mirroson ic (12 LPs)
no w a va ilabl e>.
On l y a bri ef note to signalize th is rath e r
hu ge project, n ow being issued volu me by
volume. The Congress is of British, A_m er ica n ,
a n d Ca na di a n organ ists of trad it ional persuasion-there isn't a Baroq ue tweet to be
he:u-d an.l'whe re on t hese yery proper a nd
discr eet Brit ish organs. You 'll call some of it
downright stuffy, but I found that, within t h e
somewbat co nservative cast of t h e whole,
t here a re in teresting differen ces in a pproach .
I enj oyed Vol. 2, a ll I've played so fa r (four
long s ides, at that) for t he co n trast betwee n
a sol id British organi st a nd a very accompli shed Ameri can player, organ ist at both a
Presbyterian church and a Synagogue in
New York .
An odd fe a ture (fo r the moment) or significance to engineer s is t hat thi s se ries h as
been cut laterlll ly-non·stereo-with the Westrex 3A 45 / 45 cutter. It's the first example
t hat I've seen of t il is usage a nd sho uld go
a w ay to prove th at a stereo cutter ca n, in deed, be used to make stan d a rd lateral masters. In terestin g. If yo u want to test quality,
get you r self one of t hese. (Each volum e has
two r eco rds . )
J ohn Sebastian Plays Sach (harmon ica).
Pa ul Ulanowsky, pf. Colu m bia ML 5264
This isn ' t as far-fetc hed as it may sou n d
- Bach on t he ha rm on ica is quite somethin g.
It's only a pleasant coin cidence t h at the harmonica player'S Ilam e fits in to the pict ure.
T he re are two sonatas on t his record , origin ally f or flute and h a rps icho rd. I'm so rry
th at a pia no is used; od dly en ough, its sound
is fu r ther from Bach t han t hat of the harmoni ca, whi ch is tr uly a mouth "organ ,"
equivalen t more or less to on e of the brigh t
reed sto ps Oil t he sor t of o rga n t h at was
Bach's ow n s pecial instrument. Aside f rom a
few bumpy places , t he harm on ica so und her e
is good for Bach a nd Mr. Sebastian's playing
is sen s ibl e lind musically in telligent.
This hal'monica i s a large chro matic instrument (it plays all t h e half-ton es) a nd
some of i ts low notes are of a most unu su al
timb'·e. Pocket h armo ni cas can't to uch them.
IE
AUDIO ETC
(f1'om pa.g e 34)
compete w i th i ts stereo tape predecessor,
t he standard stereo reel. It will outpri ce i t
so completely (on ce you have t he playing
m achine) t h at thCl'e won't be a ny competition.
Even a t t h e beginning, t h e most exp ensive stereo cartridge costs onl y a bit more
than the ch eap est standanl ster eo tap e.
38
Th e price w ill var y by length , as with present tape, but the full h our of R CA stereo
will cost only $9 to begin with a nd could
easily com e down l ater and el sewh e r e, w i th
su ccess and mass productiou. The shortest
tapes w ill run a round $5, t h e blauk cartridges, if I'm right, somewher e n ear $3.50.
You ca n ch eck t h ese prices for y ourself .
AUDIO
•
JULY, 1958
Two hours of home r ecording f or $3 .50,
hi-fi ! Pretty good.
Car tridge tap e, on th e other hand, will
compete closely with stereo disc. The discs
are tixed in price, th e tapes variable, so
comparisons ar en't exact ; but the t ape
equivalent of a $6 disc ster eo r ecord might
average around $7, for th e same music.
Pret ty close, and the added f eature of
home r ecording with the t a pe system can
easily make up the differ ence. For t he fir st
t ime, then, t ape and disc will compet e on
compar able, if not equal t erms.
Disc will surely win, in volume. E ven in
autom atic fo rm, t ape isn't a s simple nor as
convenient and quick. (You still must r ewind your cartridge, nnless yon play it all
th e way throngh, once in each direction.
You still must hnnt f or wanted item s in
til e middle. And the t ap e mechanism i s
still inher ently more expensive than the
disc- though this m ay change in time with
mass production. )
But the biggest competition, as I see it,
will be between the t ape cartridge m achine
and the present home t ape r ecorder-in all
its abounding millions. This is the r eal area
of bombshell impact , sp eaking commercially, 01' so it would seem to me.
For her e is a n ew home r ecorder tha t can
give better economy and (possibly) bett er
quality of so und at the 3%. ips speed than
virtually any present machine. For thi s big
reason, and because of its new and r adical
versatility, I susp ect that the t ap e car tridge player-recorder m ay dl'ive evel'y pl'es ent hOlne tap e l'ec01'del' stmi ght off the
lnar7cet and into li1nbo- the types u sed by
t he ordinary layman, that is.
That will be a sizeable r evolution, you'll
g rant. B ut if the cartridge is what it claim s
t o be, this is what i s bound to happen.
To be sure, it'll tak e awhile. Present r ecorders must be sold off, dl'astic r e-designing and re-tooling will b e r equired, even
with plenty of enthusiasm. The doubter s,
rightly 01' wrongly, will go slow if they can.
I'd guess that it might t ake as long as it
did to convert the disc r ecord player solidly
t o three speeds. (The f ourth speed didn't
take any time at all, but the other t hree
were a long time a' coming. )
The best thing a bout the cartridge, aside
from its simplicity, is the fact t hat it
doesn't go too f ar, that the n ew system
preser ves so much of the p r esently familiar
ways of t ape recording. You will find it
somehow heartening to see that the two
reels still go 'round and 'round, t hat t he
pushbuttons still make the tap e go forward and back, f ast 01' slow, th at you can
even get at the tape itself in quick order.
These things were cleverly envisioned. They
may have seemed like obstru ction s to the
more radical-minded; to the conservative
home user they will be assets, r emoving
t hat sen se of strangeness that get s in t he
way of all r adical innovations f or a mass
public. Excellent r eason f or wide successprovided the cartridge works.
Now maybe I'm wrong on all of this.
Maybe the RCA cartridge will pop onto the
AUDIO
•
JULY, 1958
market-in t he middle of a sea of st ereo
discs-fizzle awhile and die wit h a wet
plop. Maybe it'll be a dud. Maybe its comin g i s timed unfort unately. Ther e'll surely
be something of a howl on t his seore, any
way you look at it.
Bnt my hnn ch is that , fir st, sound qnality
find gener al oper ational flexibility ar e going
t o b e jnst right f or the intend ed uses in
t he home (even if the sound isn't perhap s
quite up t o super-hi-fi specialist standard s).
Aud, second, this cart ridge offers exactly
what is now needed f or a larger home tape
market : p ushbutton ease with a minimum
of complications and of strangeness, a
maximum of economy, adaptability, depe nd ability . A big order, but t his cartridge
conld fill it. It conld have been so much
wor se ! It could hardly be better and b e
pu shbutton too.
As to sound qu ality, I r emind yon t hat
this colnmn a good many years ago ( AUDIO
E T C, Mar ch, 1955) devoted two enthusiastic months' worth of comment to the appearance of the first Ampex narrow-gap
head for wide-range sound at the then slow
speed of 7lh ips. That step, applied t o the
r elatively expensive Ampex 400 models
( now discontinued ) and th en later t o t he
simpler 600 series, now 'h as reached down
to t he present hom e Ampex equipment at
a still lower price. But in the same 1)eriod
t he wider r a nge r esponse has b een applied
to virtually every home t ape machine to
SODle degree. Back in t he old days, t he
standard top limit f or 7ljz ips was ab out
80 00 cp s. N ow, almost any r ecorder call
t ake down a 12- or 15-t housand cps tone at
this speed, and the st andard 3%, ips r ecordin g gets the 8000 cps tones, f or Teasonably ullllluffled sound.
F urther progress was inevitable, as I
think I Temember obser ving. Now we have
the next step-up in efficiency : 3%, ips t akes
over wher e 7% ips formerly led th e way.
N ow we'll have adequat ely wide-r ange
sound at t he ultra-slow 3 %, ips speed, and
we double its eff ectiveness by using f our
tracks in place of two.
I know it sounds fishy. I find it hard to
b elieve that t he thing works. I can underst and why plenty of engineers ar e going
to be very, ver y doubtf ul, until convinced.
I h ave a se nse of lingerIng doubt myself ;
how is it possible to avoid serious troubles ~
Bnt this feeling, you see, is too much lilte
t hose which so many of us had when microgroove LP came in. I suspect that ill the
end, th e same clarifications, the same slow
perfection, will lead t o the same r es ults.
Good sound, excellent sound, within t he
f ramework of r equiremen ts.
You can still buy old-fashioned t wotrack, f ast-play st er eo t a pes if you want .
You can even get 'em at fifteen inches, her e
and ther e, if y ou try hal·d. If you're a
puris t of th e fir st water, with cash, you can
go right ahead and make your own 30inch tap es. But it looks t o me as if a good
segment of the home music world, a t least ,
will b e swinging over t o pushbut ton play
}£
at 3%, . We shall soon see.
Electro-Voice Ste reo Demonstration
Record ABC-Paramount EVD
Stereo Demonstration Record
Hallmark HLP310
MALLET MAGIC .-------=---'::-=-..:...:,
AFSD 1
BULLRING Vol. 4
AFSD 1835
GIANT WURLITZER
Vol. 5 AFSD 1844
BAG PIPES AND DRUMS
AFSD 1857
AUDIO FIDELITY RECORDS
770 11th AVE., N. Y. 19, N. Y.
40
With the ent ry of sever al new companies
into the fi eld in May, and the issuance by
Audio Fidelity of its second set of foul' r eleases, the trickle of stereo discs swelled
into a thriving spring freshet. Contemp orary announced a total of six, including
one classical item and its perennial bestselling jazz version of "My Fail' Lady."
Urania sched uled five, headed with two
ballets by t he London P hilharmonic Orchest r a, and Cook L aboratories was r eady
to make its debut.
In addition was the I'evelation of Rudy
Van Gelder of material mastered for E lektra, Savoy, Vox, and Boston by use of a
newly designed stereo cutting head. Said
to be a refinement of the 45/45 principle,
it was enginee red and constructed by Rein
Narma of Fairchi ld at Van Gelder's motivation, Among its features is an improved
and more direct link age between stylus and
coils, and test pressings show a high level
of r ecovery from the tapes. It will be manuf actured by F airchild. To prepare fo r the
fall market, th e majors will begin building
ca talogs this summer, making that season
one of unu sual activity for sound f anciers
and adding to the burdens of reviewers.
Two companies have simplified this problem by issuing demon stration discs. In a
joint promotion in connection with the
Electro-Voi ce line of loudspeakers, f urnitur e enclosures and new ster eo cartridges,
ABC-Paramount has placed excerpts from
its six initial r eleases on a 10-inch disc. To
introduce a new label a nd a grand total of
eleven popular and SL,,( classical albums,
Hallmark has assembled a sampler of th e
normal 12-in ch size. Though they cannot
fill all the r eqnirements of a reviewer, they
serve to lighten his load by allowi11g him
to pass some of his task on to the prospective buyer.
I am able to give an account of a critical step in t heir manufacture, however, due
to the coincidence that the same firm handled both at t his point. All th e ster eo masters were cut at Olmsted Sound Studios,
Inc., under t he direction of L ewi s G_ Whittier, chief of engin eering, who said in a
~.J]'ief outline of some of the Ilew techniques
1l1volved 111 the process, "Our primary effort
was directed at i ncr easing t he level on each
channel. I feel thi s is mo st important when
the stereo disc r eaches a mass mal'ket where
it will be played on all grades of equipment. The first releases needed the high
ga in of good high fid eli ty com ponents.
* 732 'Tll e P m'7ctvay, Mama1·oner.lc, N. Y.
" Two matching cutting amplifiers of 300
watts wer e r edesigned to allow a monaural
recovery f rom both tracks comparable to
the level of most LPs. This much gain may
not be necessary in stereo playback, but it
should not be underestimated as a f actor
in the reaction of the public to t he new
discs, Tests show them to meas ure 6 db
a bove the first r eleases."
As to another ar ea occupyiug mu ch of his
attention, Whittier would commit himself
only so far . On the delicate subj ect of compatibility, he said, "If the choice wer e mine,
I must admit I would r ath er concentrate
on the best stereo possible, but I am not
a r ecord salesman. Their reports on public
acceptance are going to carry great weight.
H is not a matter to be settled in a few
month s. Until it is, we are working toward
greater compatibility.
"In t his respect, we hfLve developed a
unique system of variable depth control. It
is designed to control th e two channels
effectively and to contribute to compatibility, It is not to be confnsed with th e
system demon st r ated by Columbia as the
principle is not the same. We are 'now doing stereo dates for several comp anies in
our studio s. There may be some surprises
when they ar e released, but I'm afra id you
must wait until t hen to see what they are.
"Our investment in a Westrex cutter has
also brought us mastering assignm ents
from Urania, Cook, Atlantic, an d Rondo,
a new label. N one of th e present r ecordings was ma de in our studios, and we did
not ma st er them in the monaural versions.
Creed Taylor of ABC-Paramount along
with J ack Hodin of H allmark, gave us
every cooperation . By now ther e is no news
in th e fact th at the problems of stereo on
discs are different, in matters of separation of instruments and fading, from those
?f ster~o on t,ap e. Everyone i s leal:ning UUl:mg t IllS penod and some companies are
finding a number of their tapes are not
suitable for stereo discs. In cuttin g a m ash 'r, we must consider each type individually to determine how best to handle it.
Ou r work will be a lot easier when procedures ar e more standardized."
The studios occupy two floor s of the
Eliza beth Arden building at 1 E. 54th
Street. Founded in 1955 by H enry C. Olm~ ted and his sou Richard to service advertising agencies, the firm cloes only about a
tent h of its business with r ecord comp~nies . Acco rding to Richard, who superVIses m any of the sessions, "Father was
always a sound JJObbyist a nd owned th e
Van der bilt Theater before the space r equirements of Broadway shows made it obsolete. I became interested while making
pllot 'films for televisi.on 011 the West Coast,
after a period in the Marine Co rps. We
AUDIO
•
JULY, 1958
CIRCUS TIME With Ih,_
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41
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Descriptive literature available
AUDIOSPEAKER
LABORATORIES
1114 East Emporia Street
Ontario, California
42
ha ve one motto-Qu ality and D elivery. A
year a fter we op ened, it was necessa ry to
a dd t he second fl oor and Whittier wa s engagecl t hen. H e helped plan the n ew layout,
~ up e r vise d its construction a n cl now makes
himself invaluable a s head of our engin eering st a ff.
One r esult of th e expan sion is r esplendently evident in the cont rol room a djoining
the lar ges t studio. It is a console built b y
R ein Nanna t o accommodat e fomteen microphones, each equipped with its own
equ alizer s. These in turn feed either A or
B channels of the ster eo console with excellent distortion charact eristics and a sig na l-to-noise ratio of better than 80 db. "It
was ahead of it s time then ," said Whittier ,
" and still is. As y on know, he m ade similar
ones f or Rudy Van Gelder and for the
hom e studio of L es Paul a nd Ma ry Ford,
a nd I believe that's all. Yon might say th at
equipment like t his brought the r ecord comp anies t o ns.
"W e have two Scully cutting la thes and
a modified F airchild. A t th at time, th e
Cinem a Engineering console was r ebuilt
and used to equip a slightly smaller stndio.
And a still smaller studio with a modified
Altec console is u se d f or r ecoi'ding, copy ing, and dubbing voice. W e h ave numerous
ta p e m achines a nd many of the copying
techniques develop ed for a dvertising ar e
a daptable to st er eo."
B efore the war, Whittier studied two
years a t the R CA Institutes, a nd while
serving in the Mal'ine Corps attended a
N avy r a dio m at eriel school. 'fhree yea rs
were sp ent with Finch T elecommunication
in engineering work ,on U HF tran smitter s
and r eceiver s a nd on r a dar equipment f o),
the Na vy. Another three years of exp eri8nce wer e ga ined with L angevin as a fi eld
engineer in broadcast and public a ddress
work. Then came four year s with the Voice
of A merica in studio f a cility engineering.
B efor e his present position, h e was r ecording equipment service manager at F a il'Child
fo r three year s. N umbered in his sta ff of
se ven a r e I an Thomson, Bruno Vineis,
D a vid D e N oon, Joe Ryan, Ama truto and
Don Young, and Fred Roberts is righthand t echnical engineer.
"Quite a bit of my inter est centers on
th e new cartridges," concluded Whittier.
"W e try each oue a s it b ecomes available
but now h ave only one m agnetic, an Audio ger sh-S tereotwin, in addition to the cer a mics. When h er e on a visit, t he man a ging
director of V eg a, a Fren ch recording company, conviv ced u s he needed our F airchild
and we ar e awaiting a r epla cement. "
Aimed at the h eart of the m ass market ,
both r eleases r ely heavily on popular and
semi-popular m at erial. A short n arration
by Bill Lipton 011 the Elect ro-Voice disc
introduces the new dimen sion in sound and
provides t est t ones for set t ing the volume
of each sp eaker. His only claim of comp atibility i s f or the car t ridge. The excerpts
a re from E ydie Gorm e V amps the Ro aring
'20s (AB CS-218) , More College Drinking
Songs (A B CS-2 19 ), Hi-Fi in an Oriental
Garden ( AB CS-224 ), World W ar II Songs
( AB CS- 222), F elTante a nd T eicher ( AB CS221 ), a nd a Stra uss waltz album (AB CS143) . It was pressed by Raleigh Records
Inc.
The H allma rk disc seems designed for
use in r etail store demonstr a tions of its
p ack aged phonographs as each side duplica t es t he oth er . Introduced iu glowing
t erms by D el Sharbutt, t he m a t eria l illcludes a train ar rival and a p a ssing D C-7,
in pla ce of th e t est tones, b efore descending into an echoed Di ck H aymes vocal and
r ock and roll . N one of the classical items
is r epresented and only a small numb er of
t he pop ul a r. A b etter idea of t he lab el's
\\'ork is given by Th e Empire City ~;: x , nil
ea g er youug dixielancl group, on HLP 312.
Ju st how quickly st er eo intends to r each
a ll levels of distribution can b e seen in t he
fa ct that H allma rk is owned by P a r a moun t
Enterpri ses Inc., which h as previously
manufacturecl in its pressing plant only
Hollywood, a low-priced lab el sold in 'Wo olworth's. D espite the similarity in n am e,
ther e is no connection b etween the two co mp anies. N ei ther is t rying to sell st er eo to
be played mona urally, indicating their b elief that the new m edium i s g oing to catch
on with th e public. Due t o th e val'iety of
r ecording t echniques u sed in st ereo at this
st ag e, i t seems th a t the samp ler , a b sent
f rom the LP picture unt il fairly late, can
render a r eal service.
Th e cunent Audio Fidelity r eleases also
h ave an apprecia bly higher level. The first
discs wer e master ed b efore W estrex modi fied its 45/ 45 cutting h ead by t he addition
of a damping device. Th ey a r e L eon Berry
a t t he Giaut Wurlitzer , V ol. 3, (AFSD
1844 ) , Lionel Hampton (AFSD 1849 ),
N inth R egiment Pipe B and (AF SD 1857 ) ,
a nd Dukes of Dixi eland on Bourbon Street
( AFSD 1860 ) .
Brunies Brothers Dixieland Jazz Band
American Music ALP651
~'hi s is on e of t he most welcome releases
of recent month s, not on ly on its own term s,
but beca use it sigual s the res ump tion of u
label which has f ollowed its fo under sin ce
1942 to its va rious r esidences throughout t he
midwes t. Duriug th e '40s, it boasted a comprehensive ca talog by New Orlea ns mu sician s, ma ny of t hem previously unrecorded,
as pl ayed in their local haun ts. Now settleu
ill th e ci ty as propri etor of a reco rd sho p at
600 Cha rt res Street, its owner weut to B ilox i,
1I1iss., to ta pe this Sat urday night dance session, his fir st s ince 1949, by a ba nd led by
two of the s ix Brunj es broth er s .
On e of the contributors to "J azzmen, " t he
fi rst book to examine th e s ubj ect with a ny
au thenticity, Bill Ru ssell has combin ed hi s
reco ruing acti vities with a long and in tensive study of ja zz backgrounds. Soo n a fte r
thi s reco rd was released, bis pers istence was
reward ed by a grant of $75, 000 from the Fo rd
Foun dation to develop, throu gh t a ped in te rview s with survivin g mu siCian s, a systema tic
oral history of the 1S85 to 1917 period of
ja zz in New Orleans. The f und s will be ad ministered by the hi story and mu sic depa r tments of Tulane University.
Aiding him in th e five-year proj ect will be
Ri cba rd Al1eu , who en co uraged Sa mu el
B a L'~
clay Cha rters I V, in a preliminary st udy
"J azz : New Orleans 1S85-1957." Published
as on e of a se ries of monograph s by Walter
C. Allen of Belleville, N.J., a precedin g volum e on King Joe Oliver i s no longe r in prin t
in t hi s co untry. It is s till availabl e to members of th e .Jazz Book Clnb, 38 Willi am I V
Stree t, L ondou, En gl a nd. .A. yea r's s ubscrip-
tion brin gs six reprints of wor thy jazz books
at a cost of less than one dollar each.
B efore makin g t he ir b eadquarters iu B il oxi ,
Men itt and Abbie Brunies led some of the
most famous Chicago a nd New Orleans Dixieland groups, but have not recorded in more
t han t hirty years. Unlike hi s wander illg brot hers, Abbie never lef t t he south and is bes t
known fo r his ra re collecto r's items by hi s
H alfway Hou se orchestra of 1919 to 1926.
with clarinetists Leon Rappolo 0 " Sidn ey
Al'odin. His trum pet s tyle is always melod ious and makes up in s uren ess wba t i t ma y
la ck in fi re. Merritt mad e f our teen sid es wh en
hi s band, with brothel' H enry, foll owed the
New Orlean s Rh ythm Kings, fea tu rin g broth er
George o n t rombone, in to Chi cago's F ria rs
Inll. He return ed south in t he late '20s, and
now plays vah' e trombone in the t ypica l
Brunies mann er.
'l' he present group has worked together fi ve
:r ears and js uJJ compromis ing in i ts view of
ea rly D ix ieland , play ing with th e rel axed beat
a nd smoothly-wove n ensem bles of long acqu a in tan ce. "W e're f ake rs ," lVl e rritt notes,
",]?h el'e's only o ne ma n in th e band t ha t reads.
AUDIO
•
JULY, 1958
Ii"
When we play, we play from the heart, andUul/illiJ,
unmasked in Jordan 's solos , a ll .l
we get that good o ld socle rhythm, and that's
the sev~ n -bar phrases of Melancholy Mooel .
what counts."
Inclu ded are SalMi, an early effort, and III
Jules Galle, a clarinetist with a heautiful
Wind. Throughout, Silver draws nuances fro m
low register and agile upper tones, plays best,
the band as nImbl y as h e does fro m the leeyhavin g bought his Al bert system instrument
boa rd in hi s own pungently worded solos.
after hear ing Rappolo one n ight. Eddie James,
the on ly member under fifty, i s a strongly
Mike Sarkissian: Grecian Holiday
rhythmic p ian ist. On bass is Tony Fountain ,
Audio Fidelity AFLP1866
a co us in of Pete Fo un ta in of Lawreuce Welk
notoriety. And the tom-toms of drummer Joe
For a likely b it successor to bis "Armen ian
Wentz g ive t b e deligbtfu ll y m u ffled sound of
,~r edd i ng " set, 1\Iichael Sarld sian leaves t h e
the bru ss-stud ded Chinese r elic of another
lllountainous regions borderin g t h e B l ack Sea
day.
to visit the sce ne of s imilar festivities a l ong
~' b e progra m lists the Dixiel and class ic
the fabled s bore of the Aegean . The shift in
Ze1'o, T ';n Roof Blu.es, a nd Jazz Jlfe Blues, plu s
locale finds his Cafe Bagdad en sembl e in a
such Brun ies specialties as Till We Meet
land where East meets Wes t. Its oriental inAga.·;n, L et Me Call You Sweetheart, and It' s
strume ntatio n is fully at home in th e musi cal
l angu age of t h e country s ide, H e r e the cerea. S;n to Tell aLAe. Botb brothers sing on
Angry, t h e fam ily anthem. Because it was
monies atten dant on a weddin g may l ast sevtaped on l ocation, the record in g has a nateral w ee les anu [he eve nts of th e da.y are fu ll
of holi day spirit. Each Greek province or isural dance hall sound and is quite a bit l ess
plagued by disto r tion than earlier efforts.
l and has its characte ri st ic dan ce and t h e
Prospects of a n oral history give r ise to the
hope t h at f un ds may beco me availabl e to preserve other aspects of t hi s native Amer ican
m usic. If sent out into t h e byways, a station
wagon fi lled with good equipmen t, sim ilar to
t he one ou tfitted by Mercury, cou ld accomplis h wonders.
tempos can be mild or stre nu ous. As before, :J.
choral gro u p outl in es the s im pl e pattern s of
sultry t hemes to prepa r e the w ay fo r the endeavors of t h e dancers. Strange in strum ents
a nel sound s in an excellent r eco rding make
th is a n unusual li stening ex perience.
Wilbur Ware: The Chicago Sound
Riverside RLP12-252
Max Roach: On The Chicago Scene
EmA rcy MG36132
Chi cago still trains its s hare of young mus ic ian s, but often tbey must seek recognition
in g r eener pastures, due to the concen tra t ion
of record co mpanies on eit her coast. ~'o spotlig h t some recent g raduates wll0 b ave g ra vi·
tated to the East, Riverside presents bassist
Wilbur War e in t h e company of John J enkin s,
alto sax; Johnny Griffin , tenor sax ; Juni or
Mance, piano; and drummer Wilbur Campbel l.
After a si ngu larly effecti ve r e vi ew of r Ufli·
Brownie McGhee And Sonny Terry Sing
Folkways FW2327
Formed after years spen t in perfectin g
their individual ways of pl aying coun try
blu es, the partn er s hip of Sonny Terry and
B rownie McGhee is based on a long f ri en dship . Coming at a stage in their developmen t
when they are ready to jOin in t h e give and
take of collaboration, it enriches the work of
both singers. In remol ding their styl es to
m esh in a pleasant bl end of vo ices in severa l
duets, they retain a creative freedom which
makes familiar them es, s nch as t h e saga of
John Ifen1'Y~ ta);;:e on new fo rce a n d m eaning
in theil' in terpretation. Son n y's cu stom of
pun ct uating his harmonica sol os with quain t
falsetto cries is abandoneel in favor of the
str ong accents of Brownie ' s guitar.
Besides a E uropean tou r this summer , their
teamworl{ h as won them a firm pl ace in fo llesi nging circles a nd l ed them to fashion original urban bl ues a l ong t h e lines of I f You
Lose Yom' Money, and I Love Yo ·l t, Baby. On
these, and t h e basic rhythms of P"ea chin' The
BInes, th ey are j oined by the firm beat of
drummer Gene Moore. I n a concluding t ribu te
to Huddi e Ledbetter, they recapture his vita l
drive on Best Of ]i'dends. Even when poorly
recorded the T erry harmonica was an a mazing
inst ru ment, and h er e in good sound the fu llness of its harmony in the accompaniments is
~/I
(,Ii
tfol'e'7
it
"
I t ' 5 not H'1- F'1 1'f ((
' d oesn ' t
have Tung -Sol Tubes'
a l'evela tion.
Horace Silver: Further Explorations
Blue Note 1589
By n ow the period ic rel ease of a n ew Hornee Silver a l bunl is greeted as all event in
mod ern jazz, both for the interest of his compositions and the i n c reasi ng i n tegration of the
group cen tered on hi s highly personal piano
styl e. Cliff Jordan mak es his fi r st r eco rded
appeal'HDCe in t h e tenor sax ass ignnlent he
too k over l ast s u mmer, and fits t h e lm ubby
texture of the group admi r abl y. In pulling his
weight besi de trumpeter Art Farmer, h e ass um es new stature. With drummer Louis
Hayes and bassist Teddy Kotick both capabl e
of developing his rhythmic id eas, Silver h as
a swift vchicle for project ing a pass in g fancy
or siftin g an untried concept. It g ives his exploration s an adva n tagc enjoyed by too rew
lende r s, and he consolidates hi s gains on n
firm base before moving ahead.
At t h e moment the rhythms w hi ch permeated Sel1o,' Blues, the most r esurgent example
of the Latin phase of his career, seem to be
assimilated so well that he can call u pon them
at w ill , d istr ibuting t hem intermittent'l y as
added sp ice to n ew works s uch as PY'rMnid ,
a Near-Eastern theme modis h ly stated by
Farmer, or the balladic Moon Rays. Combined
with t h ese d iscr eet accents, m ore fu ll y abso rbed as jazz than ever befo r e, is h is growing concern for form and con st ru ction on TllC'
AUDIO
•
JULY, 1958
What we're d~iving at is the simple fact that Tung-Sol Audio
Tubes are preferred by makers
of the finest Hi-Fi equipment.
TUNG-SOL ELECTRIC INC.
Newark 4, N . 1-
~TUNG·sor
AUDIO TUBES
43
First at LEONARD RADIO
ments on h is Ma1nma-Daddy, Ware solos on
7' h o Man I L ove, Body and So"l, and turns
Lu.llaby oj th e L eaves into a vehicle for exten ded improvisation. J enld n s co n tributes
La.tin Q"a1·te,·s and Be-Ware, and Gr iffin
s hows the beneficia l effects of h is stint with
t he J azz Messenge rs. 'rhe lea der makes the r eun io n complete with his tu n e d ed icated to
• • • •
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I n hi s Chicago ex cu rs ion, Max Roach pre"iews the a biIi ties of fou I' jazzmen st ilI developing in its e n ,· irons. There is the pianist
Eddie Bal{er , w h o d emon strates an affinity fo r
the bl u es on his original Memo: 7'0 Ma1t1"ice.
to work with bassist Bob Cr anshaw in the
rhytbm section. George Coleman, an incisive
mo dern ten or saxist, is able to soften hi s ton e
on the ba llads My Old Flam e, Sf.ella By Sta,'l·jght, and his own Shi,·ley . On trumpet is
Booker Little, a 19-year-Old studen t at the
Chicago Conservatory of Music, who se feeling fo r jazz is unimpaired by his academic
pUl·sui ts. In giving gu idance to s uch a will ing
g r ou p. Roa ch is at his best, never push ing the
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to h old t he attention of a late even iu g
of mCl' l'ymRkcl's, offe r choice bits of
uninh ibited performances. To rec r eate
associated with Fats Waller, t h e s mall
g r on p used on to u r by D i nah Wa shi n g l"on is
en larged to a big band conducted by El'Il ie
W ilkins, who r efurbi shed the scores with hi s
customary s k ill. Dinah puts ly r iCS to J ·jtt er b1l.g We,ltz fo r t h e first t im e, reva mps B I.ack
and Blue, and makes Cht'istophe,' Colu1I1bus
s ingabl e by giving it a blues flavor . Tbe tcnorsax of Eddie Ch amblee, h er hu s band and voca l
pa r tner on Eve'rllbody Lo ves My Baby a nd
[Jon eys'/lck l e Ro se, is featured on I ' ve Got a
"POINT ONE"
$55 .00
York 7, N. Y. COrtlondl 7·0315
Circle 44
SPEAKER MANUFACTURERS
Are you interested in making an electro-dynamic, opencone speaker requiring no baffle, and having almost the ideal,
pulsa ting -sphere polar characteristic? Our Patent # 2,83 2,843,
issued April 29, 1958 to B, F, Miessner, is available for license.
Write to:
Miessner Inventions, Inc"
Van Buren Road, Morristown,
Tel: JE 8-4590
New Jersey
=
44
AUDIO
•
JULY, 1958
Peel'ing I'm Palling, Other soloists are Renauld Jones, Cha rli e Shavers, J erome Richardson, Frank Wess an d Jack Wilson , her
regu la r pianist.
Recorded befo re his usual a udi ence in the
Casba r Theater of t he Hotel Sahara, Louis
P rima indulges in extroverted byplay on
t ru mpet and in his vocals with shining spo use
Keely Sm ith, a sa ne bu t ' not restraining infl uence, He blasts Whit e Oliffs oj Dover , demo lishes Holiday fo ,' St"ings, and restores
G'reenback Dalla,' B 'il! to preinfiation value.
Prodded by tbe rOistering te nor-sax of Sam
Butera, t he Witn esses give rollicking support
on Them 7'here Eyes, Lo've Of My Life, and
7"ige,' Rag. A Las Vegas favorite fo r foul'
l'ears, Pr im a may tame the town yet.
DYNAKIT
MARK III
AMPLIFIER KITS
A great amplifier circuit of superb
listening quality in money-saving
kit form!
*
*
60 watts a t less than 1% distortion. Instan-
ta neo us peak powe r of 140 watts. 1M less
tha n .05 a t average listening levels.
Choke filtering and low noise circuitry re-
duce hu m and noise to 96 db below 60
watts.
New r ugged KT-88 tubes a nd other heavy
duty parts used conservatively.
Contemporary C3544
'1'0 date the on ly modern jazz oboist an d
an expon ent of the English horn, Bob Cooper
is here intent on exhibiting his style on tenor
MARK II
sax to best advantage. The 23-a nd-a-h alf minutes of his Jazz Th enLe a nd FO'Ut" Variations,
an un ass umin g piece with roomy solos by Vic-
tor Feld man on vibes, trom boni st Fran \, Rosolino and the com poser, fi lls one side of t be
disc. It is deceptive in i ts seem in g simplicity
and will repay repeated h earin gs. Cooper
makes this proced ure relatively painless by
avoiding the familiar clicbes of arranging in
developing the theme stated in Sunday Mood .
Arter a blnes motif, a brass sect ion of the
Can doli brothers and Don F age l'qnist on
trum pet, plus trombonist John Halliburton, is
added to the sextet f or the descripti ve Happy
Ohanges, Ni.ght Stro ll, and Sat!t1'day Dance.
That Cooper keeps hi s orchestrations clean
an d uncluttered, n ever overw riting, is a meas-
ure of his studies with Castelnuo vo-Tedesco.
The soloists are allowed considerable leeway
ill h is fra mewo rks and tbe zest ' of their response carries over to t he remainin g numbers,
rangi ng fro m a dramatic Prankie and Johnny
to Pa rker's Oonfirmation. Cooper pays his respects to Johnny Hodges on Day Dream, Feldman defines Easy Living an d pianist Lon Levy
solos on Some body Loves Me.
lE
and to attenuate those below this figure for
the tweeter. Values for 0" 0" L, a nd L ,
are calcula t ed as for 0, and L , in Fig. 4,
using a crossover frequency of 5000 cps,
the point where the tweeter takes over. This
wiring of the midrange is exactly the same
as that of the woofer in Fig . 4, except t h at
the values of its associat ed inductan ce and
capacitor are different from t hose associated with the woofer. Like the midrange,
the tweet er derives its signal across L,. L,
shuuts the lows a round the tweeter, while
0, provides au easier p ath for highs than
for lows. 0, and 0, have the same values, as
do L, and L ,.
The frequencies chosen for purposes of
this discussion are purely a rbitrary. Some
tweeters are made to take over at 7000 cps,
while still others are d es~gned to function
at frequencies as low as 1000 cps. There is
also considerable latitnde with r egard to
woofer s and midrange units.
The circuits presented h er e ar e basic, but
there are variations. Some networks are designed to attenuate the response at even a
more r apid rate than Fig. 5. Others are
provided with switching provisions, so that
a wide variety of crossover points can b e
obtained. Still others are series 'circuits;
these are more costly to build, but m any
engineers favor them over the more common parallel constant-impedance networks.
In a future installment of my other column, AUDIO TECHNIQUES, yon will find an
interesting means of making test indu ctances for experimental n etworks. Watch
for it.
IE
AUDIO
•
JULY, 1958
50 Watts
6975*
net
The Mark II is the best buy in high
power high fidelity kits
* Ease
*
Available /rOl1t leading Hi-Fi dealers everywhere
D escri ptive broc hure available on request.
NEW! DYNAKIT
STEREO CONTROL KIT
ADDS COMPLETE STEREO
CONTROL FUNCTIONS TO TWO
PREAMPLIFIERS FOR ONLY
$12. 95
D ata Sheet Auailale on Request
of assembly due to uniquely simple
circuitry a nd printed circuit construction
with factory-mounted par ts.
Highest stability using patented stabilizing
networks w ith minimum number of phase
shifting stages. Suitable for all loudspeaker
systems including electrostatic.
* Dyna
Biase t (patent pending) for simplified adjustment and complete freedom from
*
effects of unbala nced components. No ba l ~
ancing adj ustments r equired to mee t pub~
lished specifications.
Dynaco Super~Fidelity output transformer
with patented para-coupled windings. Th is
is the finest available transformer Q.f its
t.ype for the most critical a udi o uses .
*S lightly higher in West
DYNACO INC.
Expor! Division :
617 No. 41st St., Philo. 4, Po.
25 Warren St. , New York 7, N. Y.
Circle 45A
pI•
AUDIOCLINIC
(f1'om page 4 )
net
The new Mark III includes all the
sensational attributes of the popular Mark II plus these outstanding
deluxe features
*
Bob Cooper: Coop
7995*
60 Watts
Low non-II
Smooth freq
• High
• High power
various kinds of distortion,
oftenest is the non-linear
uneven distribution of the flux
amplitude of voice coil mo~
magnetic field.
The PW-ISC and PW-12C speakers are
based on strict calibration of the rna
distribution
all but to
damper.
30·4,000 cps, Impedance :
16 ohms, 30 watts capacity.
Pioneer Woofers for Clean and Crisp Sound
PW-12C 12-inch woofer
16 ohms, 20 walls capacity.
FUKUIN ELECTRIC
S Otowacho 6-chome, Bunkyo-ku ,
Tokyo Japan
Circle 45B
45
NEW PRODUCTS
• Ron..tte St.,·r eo Cal'tridge . Design e d fo r
n e w r eco rd player s a nd as a repl ace m e nt
cartridge for exis tin g phono g r a ph s , t hi s
dua l- e l e m e nt pi ckup i s co mpati bl e w ith
both m onaura l a nd ster eo r eco rd ings.
Lateral a nd vertica l co nlplia n c es a loe
un it. L ow freq u e n c i es a r e r e produ ce d by
a hi gh-effic i e n cy woofe r p r o p erly l oaded
wit h a fo l d e d expon ential horn, w hile
hig h s a r e h a ndl e d by a w id e-angle tweeter
completel y protected against a ll c lim a ti c
co nditions. Power h a n cUin g ca p acity i s 1 5
watts. B e ll openi ng i s 15 ins. a nd d epth
i s 11 in s. For f ull inf o rm a ti011 write Atl as
So und Co rp o r atio n, 144 9 39t h St., B r ook l y n
G-3
18, N. Y.
• De,Wald Stereo/ Monaural Tune·r . This
tuner can b e use d for stereo r eception or
in t h e co n ventional m a nn e r fo r monaura l
FM or AM broadcasts. Design ate d M od e l
1000, i t conta in s e i g'ht t ub es p lu s diode
a nd r ect ifi e r. Th e un it in co rpora t es fo ur
s t ages of i. f . in c ludin g di scriminator an d
standa rd tape t r a nsport ; a uxilia ry inpu t
is prov id e d for t a p e preamplifi e r s. Tun e r
s pec ifi cati o n s a r e : FM sensiti v i ty, 3.5
microvolt s fo r 20 db qui e tin g, 6.0 microvol ts for 30 db quieting; AM sensiti vity,
20 mi crovolts for 20 db quieting. Fre -
q u e n cy response on Fl\1 i s 20 t o 20,000 cps
± 1.0 db ; on AM, 20 to 5000 c p s ± 3.0 db.
state d by the manufac tur e r to b e 3. 5 x 10-6
dyn e/cm. Opt Imum stylu s press ure i s
s p ecifi e d as 4 to 6 grams. Frequen cy response is said to b e fi a t from 20 to 12,000
c p s . Th e cartridge u ses a c lip-on stylu s.
Th e Ronette Binofiuid cartridge i s dis trib u ted in th e U . S. by Rone tte Acoustica l
Corpo r a ti o n, Lynb r ook, N . Y .
G-l
• S te,r eo Magnec ordette. Engineere d to
perform with profe ss iona l q u a lity, th e
n ew Ste r eo M ag necor d ette i s a h ome instrum e n t which i s cap a ble of both r ecording an d r e producin g ste r eo ph on i c so und,
a s w e ll as standard mon a ura l half-track
s ignals. Ster e o h ead s a r e of t h e stacked,
or in-lin e, type and recording speed s of
standard models are 7.5 a nd 3.75 ips, w ith
1 5 ips a nd 7. 5 ips ava ila ble on r equest.
Frequ e n cy r esp on se is 50 to 12,000 cps
withh1 ± 2 db a t 7.5 ips; 50 to 6000 c p s
within ± 2 db a t 3.75 ips, a nd 40 t o 15,000
a utomatic f r eq u e n cy con t r ol. Hou sed in a n
attractive b lack a nd gold case, the m od e r ately -pri ced Mode l 1000 measu r es on l y
1 3" w x 41,{." h x 9" d . Manufact ure d by DeWald Radio, D iv i s i o n of United S ci en tifi c
Labora t ories, Inc., 35 -1 5 37t h Ave ., Long
Island City I, N. Y.
G -"
100 to 7000 c p s. L a tera l co mplia nce is
3 x 10'" c m / d yne ; vertica l co mplia n ce i s
2 x 10'" c m / d y n e . R ecomm e nde d l oad, eac h
c h a nnel, for f lat r esp o n se i s 0.1 m ego h m .
Recomme nde d tracking force i s 3.5 to 7. 0
g r a ms. Th e cartridge has a dua l mu - meta l
shie ld to protect again st hum, a nd a
highly- fiexi ble grou nd strap d esi gn whic h
a llows it t o b e u sed in e ithe r a three-wire
o r a fo ur- w ire ster eo system. Th e s hie l d
a l so m a y be g r o undeel i nd iv i d u a ll y with a
se p a r ate wire . Sty lu s r e place m e nt i s
s imple . Fu r th e r infor m at io n o n t h e G -E
s tereo cartridge is avai la bl e f r o m: Sp e c ia lty E l ec troni c Co mpo n e nts Departm e nt,
Gen e r a l E l ect ric Com p a ny, Auburn, N. Y.
G-7
an d a m atch e d fo u r -way s p eak e r system
in a n aco u stically isola t e d ell c los u re.
S upplie d with complete o p e r a ting instru c tio n s, a nd a n necessar y m ate ria ls for th e
s impl e conversio n, the SA- I032 m ay be
u sed w i th a ny ster eo pic l{up cartridge ,
according to the prefe r e n ce of the user.
Conte mpo r a r y in sty l e, t h e unit m eas u r es
28 1h"h x 25o/..'w x 16'A, " d an d is avail a ble
in a c h o ice of fo ur finiSh es-co rdovan ,
c h err y o r bl onde 111a h ogan y, or Anl er i can
walnu t. P il ot Radio Corpor a t i on , 37 - 06
36th St., L011g I s la nd City I , N. Y.
G-5
• Bell Tuner-Anlplifier. Th e n e w B e ll
Mode l 2521. co mbin es a n FM-AM tun e r
w ith a 15-w att high-fide lity a mplifi e r on
a s in g l e co mpact c h assis. A m on g feat ures
of th e t uning unit is a uni q u e "el ectroni c
t unin g bar" , in ,vhic h segnl e nts of a brok e n ba r of light co m e toget h e r to indicate correct t uni ng. A F C may b e dis abled a t w ill. A m u ltipl ex o u tput on t h e
rear of the c h assis will fa c ili tate the
r ecep tio n of a ll-FM ster eo broadca sts
when t h ey become availa bl e. Inp u t for
tape h ead is eq ua lize d
to stan d a rd
NARTB c ur ve, maki n g it possibl e to pla y
back d i r ect f r o m th e ta P f : h ea d of a n y
46
Chann e l separation i s 20 db, n Olll in a l , frOlll
II P ilot Stereo Conversion Console. In tro duced as t h e a n s wer to m a n y requ ests
r eceive d f rom ow n e r s of Pilot mona ura l
high-fide lity systems who want to con vert
to stereop h o ni c oper ati o n, t h e Mod e l SA1032 a mplifi e r- speak e r unit conta in s the
new Pilot AA- 903B a mplifier-preamplifier
c p s wi t hin ± 2 db at 1 5 ip s. Signal- to- n oise
ratio is a pproxim a tel y 50 db. C h a nn e l-to c h a nn e l c r osstalk i s down m or e than 50
db. Th e unit is e quippe d w i th two hi gh impeda n ce microphon e inputs a nd cath odefo ll ower o u tp u ts. M a t c hin g VU m e ters
a r e provided fo r monitoring both input
c han n e l s. T hree gain controls p ermit individ u a l a dju stm e nt of each c h a nne l, as
w e ll as m as t e l" c 011tro i of both s imulta n e o u s l y . Altho u gh n ormally s u p plie d for
pl acement in the u ser' s e x isting cabinetry,
the Stereo Magneco rdette i s availab l e w i th
c u stom cases a nd cabinets w h e n d esire d.
P a n e l dim e n s i ons of the a mplifier uni t
a r e 5 14 x 17 in s ., the ta p e t r ansport i s
7 x 17 in s. Magn ecord Divis ion of M idwestG-2
e rn Instrum e nt s, In c ., Tu l sa, Ok la .
• Atlas
Coax
Weatherproof
S peaker.
Suite d fo r both voi ce a nd m u sic, t h e A tlas
C oax Pro j ector Model WT-6 in co rpora tes
two indiv idua l driv ers, each with its own
horn , a nd a b uilt -in e l ec tronic c rossover,
a ll combin e d in a s ingle w eath erproof
r.rhe a nlplifi el' s ec tio n has r ated po ,v e r outp u t of 15 watts a t l ess t h a n 1.0 p e r ce n t
distorti o n , with f r e q u ency r a n ge of 20 to
20,000 c p s ± 0.5 db. B e ll Sound Syste m s,
555 Marion Roa d, Co lu mb u s , O hi o .
G-G
II G -E
Stereo Cal;;'ridge. Anno un ced as
bein g avail a ble to the con s um e r marke t in
A u gust, th e n ew G -E stereophon ic car tridge w ill be sup plie d in two m o d e ls-the
" Golcle n C lassi c" a nd th e "Stereo C lassi c",
differ ing onl y in the fac t th a t t h e fo rm er
w ill hav e a 0.7 - mil diamo nd stYluS, w hile
t h e latter w ill b e e quippe d with a 0.7-mil
sapphire. Both mode ls m ay b e u sed in
eith er high-qua li ty r ecord c h a n gers or
t urn tabl es. Freq u e ncy r es ponse i s 20 to
17,000 c p s. O u tp u t is 1 0 mv, n omin a l, per
channe l a t sty lu s vel ocity of 10 c m / s e c .
• Harman-Kardon Sterec> A1nplifier. Intro duce d as p a r t of the Harman -Kardon
"Cr est" ster eo lin e, the n ew " Trio" Mode l
A - 224 stereo amplifier i s, in essence, three
i nd iv idua l in str um e n ts. It is a compl ete
stereo a mplifier w ith two sepa r ate 12-watt
powe l" am plifi e r s; it can b e u sed as a com ple t e 24 -watt m o n a u ral a mplifi e r, a nd i t
is a lso a 24-watt mon a ura l a mplifi e r with
comple t e stereo preamp lifi er so a r range d
that a n e x is tin g m on a ura l a mplifi e r m ay
be in corp o l'ated in to a ster e o system. Feat ures include: separ ate ganged bass and
treb le contro ls , b a l a nce contro l, rumbl e
fi l ter,
mode s witc h , s p eaker
sel ectol'
switc h, con to ur co ntro l, a nd ta p e o u tput
(a fter tone control s) for r ecording. Manu fact ure d by H a nn a n-Ka rdo n , In c ., Westbury, N . Y.
G -g
AU DIO
•
JULY, 195&
• "Mus ic Mind~r. " T h a nl( s to t his d ev ice,
t h e 1l1u si c l ove r ,vho e nj oys li ste nin g t o
reco r ds wh il e r e laxing may d o so with out
t h e irksome task of t u rning off t h e hi-fi
sys t e m afte r t h e las t r ecord h as played.
T h e M u s i c Mindel- performs t h e j ob a uto maticall y . Operation is co mplete ly e lec trical. Th e r eco rd c h a nger is plu gged in to
-.-----
......
" ... Uncanny smoothness and un·
obtrusiveness ... a spaciousness
of sound which sets it apart from
most other tweeters. There is no
audible pattern of directivity in
the horizontal plane . With the
JansZen speaker, the entire ap·
parent sound source broadened
out ... sparkingly different from
other tweeters. Instrumental com·
binations which had been sub·
merged on other speakers emerged
with startling clarity."
o n e of two sock ets, t h e r e m a ind e r of the
hi-fi syste m into t h e oth e r. If the u ser
does not want t h e a utomatic fea ture h e
s ilnpl y sets a n "au to -nl a nual" s\vitc h to
t h e m a nua l p ositi o n . L i t e r a t ure is avail a b le fro m C. B. C. E lectr o ni cs Co ., Inc. ,
2601 N . Howard St., P hila d e lphia 33, Pa.
Model 130
Th e Au dio leagu e Report.
Authorized quototion No. S2
G-IO
JansZen*
• Head Den1agne.t izer. Featurin g a t hin
exten d ed pole piece w hi c h fit s m ost tape
reco ,-d e r s w itho u t a n y di sasse mbly, the
M od e l HD- 6 d egau sse r co n s is t s of a 110vo l t 60 cps co il in a h a n dfitti n g phenoli c
h o u s in g. Co n tact of the en e r g ize d pol e
pi ece with t h e po l e tips of th e reco rding
DV'NA.N1IIC
,'".",.--------- ..... .....,
//~/
I
I
I
The JansZen Dynamic sets new
standards in cone woofers.
Unique design concepts, com·
bined with new materials has
resulted in awoofer system which
can be used singlyor in pairs with
the JansZen Electrostatic.
,
I
I
I
I
\
\
h ead ca u ses t h e h ead to b e saturated by
a n a ltern atin g mag n e tic fi e ld. Grad u a l
r e m oval of t h e satu r a tin g fi e l d f r o m t h e
h ead n e utra li zes a n y residual p e rm a n e n t
(d. c.) magnetism. Th e HD-6 i s m a'nu fact ured by Robins Indu stri es Corp . 36 - 27
P r i nce St ., Flu s hin g 54, N . Y.
' G-ll
\
\\,
'''''' '
.............. _----_...........
The Z-200 System
Model 250 measures only 18Y. " high
(exclusive of legs) by 24Y. " wide by
14" deep
..........
Acomplete range loudspeaker sys·
tern using the incomparable Jans·
Zen Electrostatic mid and high
range speaker (Model 130U) with
the new JansZen Dynamic.
The JansZen Z·200 was picked by
the Institute of Contemporary Art
as The high quality loudspeaker in
its PiTce class and above for ex·
hi bit at the U.S. Pavilion of the
Brussels World's Fair.
AMPLIFIER
([1'om page 20 )
tinue to be true when the Dynamu head
was r eplaced by the Brush unit. However, a different and mOre workman like
shielding measure was employed, with
considerably greater effectiveness tban
the g immi ck.
A small piece of Co-Netic Shielding'
was affixed to the reverse side of the
bracket that holds the pressure pad on
the tape transport. The material is
almost paper-thin, cuts easily with a
scissors, is easily worked by fi ngers or
simple tools into the desired shap e, yet
is r ig id enoug h to hold this shape, and
does not lose its shielding properties
because of shock, r ep eated bending, temperature cha nges, etc. Several layer s of
Co-Netic material were used, each layer
..................
AUDIO
•
JULY, 1958
_---
Model Z·200 measures only 32" high
(i ncluding 4" legs) by 24Y." wide
by 14 " deep
"'Desig ned by Arthur A. )onszen
NOW more than ever ...
Hear the Music, not the Speaker
Write for literature ancl the name of your nearest clealer
Products of
1 M a d e by
Perfection Mica Compan y,
1:::22 N . Elston Avenu e, Chicago 22, Illinoi s.
."",.------
NESHAMINY ELECTRONIC CORP.,
Neshaminy, Pa.
Export Division: 25 Warren Street, N. Y.C . 7 • Cable Simon/rice, N.Y.
47
build what it takes
to get the best
high fidelity
SOUND REPRODUCTION
IT TAKES THE FINEST OF COM PONENTS
- PRECISION JBL SIGNATURE LOUD SPEAKER UNITS-
THE 0 130
THE 175 0LH
OR THE 075
EXTENDE D
HIGH F REQUEN CY
HIGH FREQUENC Y
RANGE SPEAKER
ASSEMBLY
UNIT
- to get the best in high fidelity sou nd. And to get all
of the rich, crisp, accurate, deep down bass ge nerated
by your 0130 , you must mount it in a carefully constructed, engi neered acoustical enclosure. One of the
most popular enclosures ever made, beca use of its compact dimensions and smooth, clea n re sponse, is the
JBL Harkness Model C40 - a back·loaded folded horn.
Sound below 150 cps is radiated from the back of your
0130 through the horn. Above 150 cps th e speaker acts
as a direct rad iator. The six foot lon g, exponentiallyflared horn path is inge niously fol ded within sleek,
low enclosure measuring only 38 " wide . The horn is
completely containe d wit hi n th e enclosure and is
independ ent of room walls.
Prov.e your woodworking skill and get
th e greatest thrill hi gh fidelity can
give you. Here is a project that will
make use of your finest cra ft smanship
for the enjoyment of yourse lf and
your family-a project you ca n show
off to others wi th pride. Detailed
production prints, complete wi th a
list of parts , and step.by-st ep
instructions have now bee n released
by t he factory. The set is yours
for only three dollars.
BUILD YOUR
C40 FROM
PRODUCTION
PRINTS
I
!
I
JIl
r-I
I
I
.,
ures was to reduce noise and hum in the
tape amplifier substantially below that
inherent in the tape itself, namely tape
hiss. Even when a tape has been caref ully bulk erased, leaving it as noisefree as a tape can be, it still makes the
dominating- contribution to noise on the
writer's tape recorder, Considering- the
additional noise produced in recording
- at least modulation noise if not also
noise due to distortion in the bias waveform-it may safely be said that the
tape electronics described here do not
constitute a limitation to signal to noise
ratio in tape recording and playback.
On the other hand, it is to be expected
that eventual improvement in the tape,
resulting in less tape hiss, 'will inspire
a search for further means of reducing
noise and hum.
Stereo Playback Amplifier
There is an increasing demand for a
second playback amplifier for stereo
purposes. A simple way to satisfy this
demand would be to construct a one-tube
affair, either on the main amplifier chassis 01' separately, patterned after the
circuit of V z and Vs in Fig. 2. Power
could be drawn from the main tape
amplifier, from an easily built supply
such as shown in Fig. 5, or from the
power amplifier of the audio system.
If power is drawn from the main amplifier of Figs. 1 and 2, connection
should be made to the point B 2+ via an
additional decoupling network consisting of another 4700-ohm resistor and
another 15-J.l.f, 350-volt filter capacitor.
Since the loading of the main power
supply is considerably lighter in playback than in record, this suppl y can
take care of another 12AX7 for stereo
playback. At the same time, however, it
is highly desirable that a switch be incorporated to remove B+ from the extra
12AX7 during record. Similarly, the
heater supply to this tube, if obtained
from the main amplifier, should be disconnected during record. On the other
hand, if the power transformer used is
large enough, these disconnections are
not necessary.
.IE
S+
r---......,.-r-<t-""W'h-~_.lIMIM.,...._---_o 250 v.
-!!..-':
USE THIS FORM TO ORDER YOUR PLANS-,
JAMES B. LANSING SOUND , INC.
I
r
3249 Casitas Ave. , Los An ge les 39 , Calif.
Gentlemen :
Enclosed find $3.00
for one set of Model C40 Production Prints.
Please print clearly or typ e your name
'J
and complete address :
I
1
I
Name
I
IL ________________
Addre ss
I
~
48
ill creasing- the protection ag-ainst hum.
Some experimentation was necessary to
find the optimum size of the Co-Netic
Shielding- and its best location on the
pressure pad bracket. It is interesting- to
note that a small section of this shielding-, about Ij2" wide, afforded considerably g-reater hum reduction than a piece
double that width. The final result was
considerable attenuation of hum. The
reduction was not measured, because
without the use of filters one would be
measuring- noise along- with hum. To the
ear the reduction appeared to be at
least 6 db.
Co-Netic Shielding- is expensive. In
small quantities it is over $3.00 pel'
lineal' foot for a strip 4 in. wide, and the
minimum order is 3 feet. However, for
the habitual experimenter or tinkerer it
can be a worthwhile investment. A less
cxpensive alternative, closely approaching- the Co-Netic material in effectiveness, is a shield made from a piece of
silicon steel I-strip. The latter material
i;:; more difficult to work and eventually
becomes mag-netized, while the Co-Netic
does not. A magnetized material adjacent
to the tape can cause erasure, noise and
hum.
For mmUllum noise and hum, an
ECC83, the European version of the
12AX7, was used for V z- V 3' Of two
Mullard ECC83's purchased, both were
excellent with respect to noise and microphonics, but one had serious hum. Demagnetizing' this tube with a bulk eraser
and resetting the hum balance pot did
not improve matters. The tube was exchang-ed for another Mullard ECC83,
which proved to be excellent. It is unfair
to draw conclusions from a sample of
three, but this experience corroborates
the writers' experience with other tubes,
such as the 5879 and Z729, that one
must be selective even when using premium types, which cost appreciably
more. The two good Mullards were definitely superior both in noise and hum
to each of half a dozen American
12AX7's in the writer's tube chest. A
couple of Telefunken 12AX7's were of
quality similar to the Mullards_
The ultimate result of the above meas-
~
6.3v.
100 O HMS, WIREWO UNO
0.6 amp.
Fig. 5 . Simple power supply circuit suitable for second -channel amplifier for stereo_
AUDIO
•
JULY, 1958
HEARING
!----~ -~r~--········~··· l
page 26)
two channels only are requi.red while in
i
Measurements of noise have also been the latter, theoretically an infinite number
is
required
but
practically
three
give
Illade in motion-picture theaters. Mueller
found the average level in theaters with- a good illusion.
In the binaural system two microout an audience to be 25 decibels and
with an audience present it was 42 deci- phones are placed in the ears of a dummy
bels. This last figure is within 1 decibel who sits in the position where the listener
of that given above for the average noise would like to sit if he were listening to
level in residences. So all the limits men- the original sound. Two transmission
tioned above for residence room noise lines meeting the requirements above
can also be applied to motion-p icture connect these microphones to two head
theaters, that is, Fig. 3 gives the limits receivers respectively, one being placed
if no limitation is to be placed upon the on each ear of the observer. With such a
system a complete facsimile of the Ol'igisounds to be recorded.
Noise measurements made in the nal sound at the dummy is reproduced to
Academy of Music in Philadelphia and the listener. The Oscar system presented
Constitution Hall, in Washington, D. C., at the W orId's Fair in Chicago by the
during a quiet listening period indicated Bell System was one meeting the str'inlevels about 10 decibels lower than that gent requirements outlined above.
given in Fig. 3 for residences. So at
I n the stereophonic system an attempt
least for these concert halls the lower is made to produce this spatial effect by
part of the shaded area should be used using loudspeakers instead of head refor determining minimum levels. It will ceivers in the reproduction. Suppose
be seen from Fig. 1 that for the average there were interposed between the source
person in such quiet intervals in these of sound and the audience which would
concert halls the lower limit is set by the normally listen to it, a sound-transparSP-210 • Stereo Preamplifier
acuity of hearing rather than by the ent curtain. A large number of micro$89.50 Jess power s
audience noise.
phones are mounted all over this curtain.
The foregoing gives the ideal limits of An ideal line connects each microphone
frequency and intensity for high fidelity. to a recording unit of a recording sysIt is well known that within these limits tem, or to a loudspeaker if a simple
the system must have a sufficiently uni- transmission system is used. The loudform response with different frequencies speakers are spaced over a similar curso that the ear will not detect it from tain when the sound is reproduced. If
one having a perfectly uniform response. the microphones and loudspeakers are
Due no doubt to the fact that persons dose together a curtain of sound will
usually listen in rooms which have res- be reproduced similar in all respects to ! SA-232 • Basic 8101110 Amplifier
Total Power Output
onances, it is difficult to detect depar- the original sound. Again three such t
64 watts peak
tures of 3 or 4 decibels from uniformity channels for most stages will give a suffiHas power tap·.o ff for SP·210
- in fact, it is very difficult to measure ciently close approximation that, due to
them. Here again it would be helpful if the limitations of hearing most observ$89.50
j
we had some precise measurements on ers cannot detect the reproduced from
this point. Also, it is well known that the original when all the other requirethe system must be linear with intensity, ments discussed above ar e met. Indeed
that is, the acoustic output must be pro- two channels go a long way toward this t
pOl,tional to the acoustic inpu t. Also ideal. However, if the sounds were not
there must be no asymmetry in the vibra- confined essentially to the level of the
I
tion during transmission. Any depar- stage but were permitted to go up and
tures from these ideals must not be down as far as they went right and left,
SA-260
larger than can be detected by the avel'- then nine channels instead of three
age ear.
would be required. Or if we wished the
120 watts peak
Has power tap·off for sp·2fo
sounds to appear to come from all diF"·~·········<
Facsimile Requirements
rections around the listeners, then chan.
~
.
l$jJ1.~_5ii_Q!
[
prices s ightly nig er in West
nels sufficient to covel' a sphere sur- L
__ ..
_ _·':;;;' _ _ _ _ _ _ _ _ _ _ _ _ _
When all of these requirements are
rounding them would be necessary.
met, a facsimile of the original source
The question then arises, how much
Radio Corporation
cannot be produced unless another facn - 04 36th St., L. I. C. I, New York
tor is considered which is sometimes loss in quality of the reproduced sound
overlooked, namely, the spatial or audi- is experienced as we depart from such
Please send literature covering
tory perspective character of the sound. an ideal ~ To answer this question we
Pilot Stereo Components.
must
know
the
kind
of
material
that
is
If we are reproducing a moving sound
___________________________
source it must appear to move, and if u sed in the transmission. Without such
ADDRESS _______________________
the sound source is broad it must ap- an ideal transmission system, there is
peal' that way when reproduced. In always placed some limitation on the
CJTY__________ ZONE-STATEt..._ __
type of material used. In general, this
nearly all systems now used this factor
material
may
be
classified
as
either
is neglected. It can be preserved in two
Electronics manuf acturer
ways, namely, by a binaural system or music, speech, or noise,
for over 39 years.
TO BE CONTINUED
by a stereophonic system. In the former,
(f1'O?n
new
ST EREOFIDELITY
components
by
Noise in Theaters
I
II
I
I
I
~
T:t~~~~w!t~~~~u~mpllfI8r
.
I
j
':!;c~":::"-'
f}Jfbtf;
NAM~E
---------------------~- -
AUDIO
•
JULY, 1958
49
The Bells Are Ringing
HAROLD LAWRENCP
A
on a bright sunny
morning in May, while fast·moving
clouds driven by a brisk wind chopped
the waters of the Hudson, a marooncolored truck' parked outside the Riverside Church. Trunks of equipment were
promptly unloaded from within the deceptively small confines of the truck. Inside
the trunks were sever al sets of cables, each
long enough to reach from the ground to
the belfry (some 400 feet), a number of
'l'elefunken microphones and their power
supplies, quantities of rope, and some
intercommunication apparatus.
The cables were unwound and laid neatly
along the entire length of 122nd-123rd
Street and Riverside Drive in New York
City. At the top of the tower, rope was
lowered to the sidewalk, the cable-ends
attached to the rope, and the cables hauleel
up to the belfry, past gargoyles and the
profusely decorated exterior of the church.
Members of the crew were stationed on
various floors of the church to help pull
up the cables and prevent th em from
getting entangled in any of the abutments.
Finally, close to four hoUl's after the
truck's arrival, all the connections were
plugged in, the microphones hung, power
supplies and tape recorders switched onand a rather unusual recording session was
in progress.
Magnetic tape recorders have found their
way undersea to pick up the speech of
fish, and atop mountains for the sound
of thnuder and lightning. Sooner or later,
someone was bound to send an expeditionary force up the walls of the Riverside
Church to r ecord the impressi"7e Riverside
Carillon. The idea behind this project was
hatched when Mercury R.ecords, whose
monaural recording of Tchaikovsky's Ove1't~tre 1812 (complete with muzzle-loaded
brass cannon and bells) is an almost
legendary LP best seller, decided to rerecord the work in stereophonic sound. The
bells used in the disc version were those
of Yale University's Harkness Memorial
Tower. For the stereo release, however,
louder and deeper bells were in order. After
scouting around for months, the nod was
gi ven to the Riverside Carillon .
A glance at the dimensions of this
gigantic instrument will suffice to explain
the reason for Mercury's choice. The Riverside Carillon contains the heaviest and
largest tuned bell in the world, a Bourdon
weighing 40,926 pounds and measuring
T EIGHT O'CLOCK
LOW FREQUENCY
LOWDOWN
The Racon model 15-HW, 15" low
frequency speaker, is now available from
stock . Production facilities have been
doubl ed and your sound distributor should
have no difficulty in fillin g your order at
once.
The 15 HW is characterized by extremely hi gh efficiency. The magnetic
" pot" asse mbly weighs 18 Ibs. , with an air
gap capable of supporting an iron w e ight
of 1000 Ibs.
It uses a patented ce llular plast ic surround, resulting in high compliance combined with pn e umatic damping. The 2"
ce ramic voice coi l is pe rmitted la rge axial
movement, without encountering mechanical rest ra ints or magn etic non- linearity.
To prevent " breakup" at high leve ls, the
mechanical ri gidity of the cone has been
increased by ce menting feather weight
stiffe ning st ruts to its rea r s urface.
The 15-HW is your best bet in a low
freq uency reproduce r if you're building a
two or three way spe aker system. Ask your
dealer for a s ide-by-s ide comparison with
any similar appearing speake r, regardl ess of
price.
Write for f ree literature.
SPECIFICATIONS
RESPONSE
20-4000 cps
POWER
25w.
IMPEDANCE
8 ohms
RES. FREQ.
24 cps'-'
FLUX
14,500
DISPERSION
100·
DIMENSIONS
15 Vsx8V>
SHIP. WT.
261bs.
NET PRICE
69.50
"Subject to production tolerances
HIGH FIDELITY LOUDSPEAKERS
~
~
RACON
E
~~M~N~'~~. C
1261 Broodwoy. New York I, N. Y.
* 26 W. Ninth St., New Y01'7c 11, N. Y.
Export: Joseph Plasencia
401 Broadway, New York, N. Y.
Canada: Dominion Sound Equipments Ltd
4040 St. Catherine St., West-Montreal 6 , Que.
50
The mobile recording plant belonging
to C. Robert Fine, who i s responsible for
all o~ Mercury's classical r ecording. ED.
1
122lj2 inches in diameter and about the
same in height. The bell may be struck by
three clappers whose combined weight is
three tons. Of the 73 other bells, five of
the bass bells are "swingers." But power
is only one of many admirable aspects of
the Riverside Carillon.
Even to the musically uninitiated, the
sound of most carillons is oddly discordaut.
This condition is caused by improper tuning. Like other vibrating bodies, the bell
produces several notes simultaneously. Unlike other instruments, three of t he bell's
notes are heard with exceptional clarity.
They are the t~mdamental, or strike note;
the nominal, an octave above the fundamental ; and the hum note, an octave below
the fundamental. In relation to the nominal, the fundamental tends to be flatter,
and the hum note sharper. There are two
princip al methods of tuning the bell; one
focuses on the fundamental, the other on
the nominal. The first i s satisfactory only
when bells are struck at long intervals,
allowing the fuller and more prominent
notes of the fundamental to r esonate. In
carillons, where the nomiual or "melody"
notes are featured, this r esults in sour
peals. If the carillon is to produce sweet
sounds, it is eS5entiai that the fundamentals be tuned to the nominals.
After the Riverside Carillon was first
installeel in 1931, it was soon apparent
that, although each bell was i ndividually
tuned perfectly, the scale was not properly tempered. III 1955, fifty-six bells in
the carillon were sent to a bell foundry in
Holland to be r ecast and retuned. During
their ab sence, New York's West Side heard
private recordings made of the Riverside
Carillon as reproeluced by a huge loudspeaker system located on the eleventh
floor. When the bells were returneel to
their home on the Hudson, the tones they
produced were supeTbly pure.
The recording session was scheduled for
Saturday morning. In case of rain, the
date was to be changed to the following
day. Wind was also a factor; the mere
suggestion of a breeze on the street became
a howling blizzard up in the tower. Fortunately the weather was perfect and, shortly
before noon, the distinguished carillonist
of the Riverside Carillon, Dr. Kamiel
Lefevere, assumed his place at the carillon
console.
n had been decided to first record an
album of Christmas music prior to unleashing the storm of b ells for the Ove1·tUl'e
1812. Consequently Dr. L efevere performed
a recital of Yuletide carols. For some
40 minutes, it was December in May for
the do ubtless bewildered residents of
Riverside Drive. Following this Ullseasonal
AUDIO
•
JULY, 1958
For the stereo perfectionist
The new ESL GVRO/~EWEL
~ No longer need perfectionists compromise with inferior or malushift stereo
pickups . From the distinguished laboratories which achieved the worldfamed ESL Concert Series and C-60 Series cartridges comes a I1e1V Iflilestone
in audio progress: the ESL GYRO / JEWEL,the stereo cartridge of tomorrow.
~ lfyou are tech~licaIlYl11inded,youlViIl bepleased to learn thatthetriumphantdesign
Fig. 1
aperitif, this writer was invited to assist
in creating as much din as was possible for
the Ovel·tul·e 1812 b ell effect. Dr. Lefevere
cordially made room for me on his b ench.
While he concerned himself with th e majority of the b ells, my job was to pound
away at a small numb er of high b ells. It
was at this point that I learned to fully
appreciate th e reason for the leather bandages which the carillonist wraps around his
fmgers, as seen vaguely in Fig. 1.
Confronting the carillon player is a keyboard comprising two rOW3 of toughlooking, rounded oak l{eys, 0/1" in diameter.
The keys are connected to wires which can
be seeu over the head of the carillonist
in Fig. 2 which activate the clapper mechanism. The player must adj ust the tension of his stroke for each bell since a
larger bell TequiTes more fOTce than a
small bell. Hand strokes aTe not employed
for the colossal six lowest bells of the
Riverside CaTillon. The upper TOW of keys
corresponds to the black keys of t he piano,
the lower to the white notes, and the
pedals to theiT organ counteTpaTt. The
keys aTe struck vigorously with the side of
the hand, hence the finger coverings. After
a brief period of striking Tepeatedly a
number of high b ell keys, my tender, b are
fingers were as bruised as a gloveless p alm
after an energetic handball match.
Carillon playing may be the most strenuous musical art, but the carillonist has two
compensations (among many others) fOT
the unusual physical demands of his profession: (1), he produces a bigger sound
than any other instrumentalist, and (2),
every time he strikes a key, hundreds hear
him.
1E
of the ESL GYRO/ JEWEL is based upon two of ESL's patented, subminiature
D 'Arsonval movemel1ts, coupled to the stylus shoe by ESL' s unique new Gyro/jewel.
~ You will be pleased, also, to leam that the E SL GYRO / JEWEL excels in vertical
compliaHce (5 x 1 0_ 6 cm/dYI1e), lateral compliance (5 XI 0_ 6 cm/dyne), dynamic
mass (.003 gt-us), chanuel separatiou (20 to 25 db), and frequeucy response
(± 3 db from 30 to 15,000 cps, lVith response extel1ding well beyol1d 20 I~c).
~ But only through actuallistel1ing can you realize the vast superiority of the
ESL GYRO / JEWEL. Compare it at your audio dealer's, al1d you'lIlVant to own
this stereo cartridge that's years ahead. Only $85; write for details.
Circle 51A
Unless hearing your favorite composer in stereophonic sound
releases a deliriously marvelous feeling within yOU ... unless
it conjures up vivid pictures in your mind's eye .. . unless it
penetrates your "inner" being . . . then you are not getting
the full impact of stereo!
To feel the gigantic realism of stereo, you mllst heal' it on the finest equipment possible ... for stereo demands the finest. Are yom'
stereo tapes played on th e .l'~"IJ~,aph
Tape Recorder, considered the world's best by
many professionals? And the new stereo disc
'.
i.;.
system * demands the very hi'ghest quality t~rntable available ... the ~dde«lf"
.' ., .>
.:'" '.
of course . . . to breathe its music through
VITA VOX DU120 Duplex Coaxial Loud- <
.;~:;;; ."
speakers for a smooth extended frequen'c y'resi;onse
and broad even acoustic distribution. Yes, for the
.. '
: brilliance of stereo you n eed good equipment!
~
':':\ .c... .
'
"watch for announcement of Connoisseur stereo cartridge
£RCONA CORPORA "'ON
(Electronic Division)
16 W. 4·6th St., Dept. 68, New York 36, N. Y.
In Canada, write Astral Electric Company Limited, 44 Danforth Road, Toronto 13.
I
Circle 51 B
AUDIO
•
JULY, 1958
51
NEW! At last . .•
"Tape Advice
in Simple American"
the
AUDIO
-ARMY TIMES
No. 110
A.coriveuientservice to AUDIO
reaqers. Of.def:your books
HANDBOOK OF SOUND REPRODUCTION
by Edgar M. Villchur
Right up to date, a complete course on sound reproduction.
Covers everything from the basic elements to individual
chapters of each of the important components of a high fidelity
system. $6.50 Postpaid.
leisur.ely by mail'-save time and
travel, we paY.the postage.
No. 111
Revised Edition
ELECTRONIC' MUSICAL INSTRUMENTS
by Richard H. Dorf
In one large volume. here are all of the
intricacies of the electronic organ and
smaller instruments. Construction drawings and details of the author's own
Electronorgan plus commercial models
such as the Allen, Baldwin. Hammond,
Connsonata, etc. $7.50 Postpaid.
No.112
TAPE RECORDERS AND TAPE RECORDING
by Harold D. Weiler
A complete book on home recording by the author of
High Fidelity Simplified. Easy to read and learn the
techniques required for professional results with home
recorders. Covers room acoustics, microphone techniques, sound effects, editing and splicing, etc. Invaluable to recording enthusiasts. . . .
No. 115
McPROUD HIGH FIDELITY OMNlaOOK
Prepared and edited by C. G. McProud,
publisber of Audio and noted authority
and pioneer in tbe field of high fidelity.
Contains a wealth of ideas, how to's,
what to's and when to's, written so
by Joel T aJI
With Foreword by Edward R. Murrow
This unique contribution to the fast developing field of magnetic tape recording translates the complexities of science to
practical easy-to-follow techniques. It is a book for the tape
enthusiast and professional who wants new ideas, new standards
of excellence in magnetic recording. Twenty chapters of kllowhow presented in simple American terms. 472 pages, with illustrations and diagrams. $7.50 Postpaid.
"There have been a number of good books on tape
recording in the past, but this one is topS."
bookshelf
plainly that both engineer and layman
can appreciate its valuable context.
Covers planning, problems with decoration, cabinets and building hi-fi furniture. A perfect guide. $2.50 Postpaid. .
No.117
TECHNIQUES OF MAGNETIC RECORDING
Papel" Cover $2.95 ·Postpaid.
No. 114
Revised Edition
THE NEW HIGH FIDELITY HANDBOOK
by Irving Greene and James R . Radcliffe
With Introduction by Deems Taylor who says'
" ... Messrs. Greene and Radcliffe, two gentlemen whose
kllowledge of hi-fi is only slightly less than awesome
. . . Read it through, alld you will arise full of kllowledge." A complete and practical guide on high fidelity;
covers planning, buying, assembly, installation, and
building hi-fi furniture. $4.95 Postpaid.
No. 118
NEW! How-to Book on Hi-Fi Repair
CARE AND REPAIR OF HI-FI-Volume
by Leonard Feldman
AUDIO Bookshelf
RADIO MAGAZINES, INC., Dept. A
P.O. Box 629, Mineola, New York
Please send me the books I have circled below. I am enclosing the
full remittance of $.; ................... ....... .. (No. C.O.D.)
Latest information on hi-fi components for efficient repair and maintenance. Complete, down-to-earth information that is not punctuated with complicated mathematics. Helpful to the hi-fi enthusiast,
technician or engineer, this first vol ume includes many important
features: Example schematics with tube layouts, descriptive illustrations and hook up diagrams, buyers' guide. 156 pages pro/ttsely
.Ll"",•• IP.d $2.50 Postpaid.
All U.S.A. and CANADIAN orders shipped postpaid. Add 50¢ for Foreign orders
(sent at buyer's risk).
BOOKS:
110
111
112
114
115
111
118
NAME _______________________________________________________________
ADDRESS_~------------_ _ _ _ _ _ _ _ _ _ _ _ __
CITY_ _ _oioiiiiO_---_- - - - - -- ZONE----STAT""E--------_
IT
A.iill
TRANSISTOR BETA TESTER
(f1'om page 22 )
the values of ~mi" and 100 + ~mi" coincide with the meter indications.
It should be emphasized that the meter
should be calibrated first to make sure an
accurate calibration is obtained for the
~ tester.
When Ro and R z are adjusted to give
the proper values of ~ at both ends of
the scale, all other points in between are
automatically calibrated to an accuracy
equal to the linearity of the potentiometer used. The points can be checked
as a matter of routine, and will be found
to coincide exactly with the dial readings. Readings with switch 8 s in the
"X2" position will be exactly one-half
those taken with 8 3 in the "X" position.
Single-turn Potentiom eter
If a more common type, single-turn,
wire-wound linear potentiometer is used
with a dial marked fl'om "0" to "100,"
tbe method of calibration is the same,
with the following exception. Since the
~mi" reading should be "5.0", and the
dial reads "0", and the ~ma", reading
should be "105", and the dial reads
"100", the user should always make a
note to add the quantity "5.0" to every
reading he makes with the instrument.
Thus, a reading of ~ = 42.0 on the dial,
really indicates a true ~ value of 47.0
and so on. This constant offset between
true ~ and dial reading does not diminish the usefulness of the instrument
!J.nd enables the builder to save the cost
of a more expensive potentiometer. A
dial can be especially made to suit the
requirements, or Fig . 4 can be cut out
and glued to the cabinet to serve as the
dial, preferably under a thin piece of
transparent plastic for protection.
Construction
+
Fig. 4. Dia l scal e may be cut ou t a nd
used wit h t he sing le-turn potentiometer.
August 6-8-Special Technical Conference
on Non-linear Magnetic Amplifiers;
Hotel Statler, Los Angeles. Sponsored
by IRE-PGIE and AlEE.
Aug. 13-15-Electronic Standards and
Measllrements Conference; Boulder Labs,
Bureau of Standards, Boulder, Colo.
Sponsored by IRE-PGI, AlEE, NBS.
Aug. 19-22 - WESCON - Western Electronic Show and Convention; Ambassador Hotel and Pan Pacific Auditorium,
Los Angeles. Sponsored by IRE sections
in LA and SF, and WCEMA.
October 2-3-Engineering Writing and
Speech Symposium~ New York. Sponsored by IRE-PGEWS.
AUDIO
•
JULY, 1958
All the components can be placed inside a 3" x 4" x 5" aluminum box. The
placement of the parts can be seen from
the photographs. All resistors and capacitors can be mounted on a small terminal board, and wires run to the battery, switches, and potentiometers as required. An "L" or "U" shaped bracket
is used to secure the battery, or it can
be mounted on the bottom cover plate.
Three type X-2146 spring loaded diode
clips (manufactured by Cambridge Thermonic Corp.) are used to clip the transistor lea ds during the measm'ement
other types may be found equally suitable.
Hi-Fi Shows
September 19-21-Chicago, Ill.; Palmer
House HoteL (International Sight gSound Exposition, Inc.)
Sept. 3~-Oct. 4-New York High Fidelity
Show, New York Trade Show Building,
New York. (Institute of High Fidelity
M anufactul·81·S).
Oct.
10-12 - Philadelphia;
Benjamin
Franklin HoteL (Institute of High
Fidelity Manufacturers.)
What do the
record people
mean by "waxing"?
[email protected]
When a Broadway columnist reports
that a young singer has just "waxed"
several show tunes, everyone understands that "waxed" means "recorded." Yet, it's interesting to note
that nobody has really "waxed" a
performance in more than 15 years.
The expression actually goes back
to the early days of recording, when
the only material on which recordings
of any quality could be made was a
wax-like compound, cast in massive
discs. Many recordists even made their
own discs by melting the compound
into a circular mold. The compound
was called "wax" and, quite naturally,
the overall recording process came to
be known as "waxing."
But the amusing thing is that even
in those days the expression was a
misnomer. Those early masters might
better have been described as "soapings" for their composition was chemically much closer to soap than to
wax.
As you can well imagine, it took experience, skill and a good deal of luck
to cut clean sound on one of those
early discs. Fortunately, in 1937 came
emancipation. That was when the first
lacquer discs appeared on the market.
They were manufactured by Audio
Devices and called "Audiodiscs." It
took just five years for the industry to
make a 100% transition to lacquer
masters. Since that time, more phonograph records have been made from
Audiodisc masters than from all other
brands combined.
Audiodiscs are still the professional's
"standard" for master disc recordings
-and this continues to be true regardless of whether the recordings are
stereophonic or monaural.
Of course, Audio Devices also did
some pioneering in the magnetic recording tape field. For years now,
Audiotape has been the choice of discriminating tape recordists - professional and amateur alike. But that's
another story. If you'd like more information on Audiodiscs (or Audiotape),
write to D ept. AA, Audio Devices,
Inc., 444 Madison Avenue, New York
22, N. Y.
Oct. 17- 19-Boston High Fidelity Show;
Hotel Touraine, Boston. (Independent).
Oct . 24-26-Milwaukee; Wisconsin; HoteL
(Institute of High Fidelity ManUfacturers. )
* one 0/ a series
53
NEW LITERATURE
WITH
Sonotone®·
STEREO
PHONO CARTRIDGES
you can
hear the
difference
When you buy or modernize
your record player, insist
on Sonotone Ceramic
Phonograph Cartridges
Circle 54A
• Cinema Engineering', 1100 Chestnut st.,
Burbank, Calif . displays its entire lin e of
precision wire-wound resistors in a new
20- page Catalog 14RC. With the issuance
of the pUblication a number of resistor
series have been r e numb ered for conform ance w ith a new specification pattern. Resistance val ues from 0.1 ohm to 20 megOhl11 8 are availa ble in acc uracies fron1
0.025 to 1.0 per cent. Nearly a hundred
types of precision wire-wound resi stors
are covered in complete detail. Requests
fo r copies s h ould be directed to t h e attention of James L. Fouch at the a ddress
shown above .
G-l6
• Panala.l.'lll Division o·f P ane·U it, Inc., 7401
N. Hamlin Ave., Skokie, Ill., producers of
annunciators and other industrial infor mation systems, is now is s uin g a fourpage folder describing a new type of
ultra-reliable annunci ator. Contained in
the folder is information on a new staticmagnetic a nnunciator recently developed
for monitoring complex a utomatic-machine and contilluous -process operations.
'l.'he unit uses static-magnetic controls in
place of conventional relays. There are
no moving parts, r esulting ill a high degree of reliability and reduced maintenance. Requests s hould specify Bu ll etin
No. 101.
G-l7
• Sp·eciaJty Electronic Components De·p t.,
Gene=l Electric Company, Auburn, N. Y.,
h as availabl e a h andsome four-page folder
w hich illustrates and describes the G -E
20-watt high-fidelity amplifier Model PA20 , the "Transi-Tube" preamplifier Model
AI - 203, and the dual-function preamplifier
Model UPX-003B. Equipped with one n -p-n
junction transistor and one 12AX7 doubletriode, t h e AI-203 is virtually free of hum
and microphonics while providing high
nominal ou tp ut voltage. The UPX- 003B is
a self-powered high-fidelity conversion
preamplifier for eith er phonograph or
microphone u se. Requests for copies of
Bulletin EP- 237 s hould be addressed to
G -EJ Hi-Fi, Box 101 Liverpool, N. Y . G-l3
• GFW Service, Inc., 1220 Broadway, New
York 1, N . Y. s uppli ers of c U$tom grille
fabrics for high fidelity, h as availab le for
d ealers a new illustrated folder which explains the co mpany's service and its
unique ap proach to grille fabric selling.
'.rhe fo lder explains that the GFW Service offers c u stomize d grille fabrics, sold
from sam ple b ook s, an d delivered to the
ultim ate customer c ut-to-size. The Service functions with out inventory or investment by subscrib ers. Copy will be mailed
to hi -fi dealers on request.
G -l4
WIDE LATITUDE TAPE
•
•
•
•
Protects against dirt. dust, mishandling.
Easy to store. • Exclusive index system.
V·slot selection·finder reel.
Tapes easily accessible.
• Amplifier Corporation of America, 398
Broadway, New York 13, N. Y., d escribes
the complete line of Magneloop continuous-loop magnetic- tape recorders-repro ducers in a n ewl y -i ssued four-page fo lder.
The brochu re compl etel y delineates features of 21 basic models, which are available in single or du a l speeds, as well as
in sin g le -, dual- and triple-channel models.
Mechanical and electrical features are
f ully exp lain e d. Complete technical specifications, recolllmended accessories, as well
as direct factory prices a r e furnished on
a ll" unit s . The brochure will b e mailed free
of charge upon written request.
G-lB
• Carte·r Motor Contpany, 2748 -A W.
George St., Chicago 18, Ill., has just released a new 28 -page dynamotor catalog
which lists the entire line of Carter rotary
power s upplies. P ublication of the catalog,
origina lly sch eduled for last Fall, was
held up when it was decided to make
major changes in 19 58 models. The catalog
lists the new Carter fan-cooled Genemotor
for the first time, as well as several new
models comprising the Genemotor lin e,
which has been materially improve d in
appearance, p erforn1an ce and service accessibility. A copy of Catalog No. 158 m ay
be obtained free upon writte n r eq u est.
E-l6
Circle 548
54
r--CLASSIFIED-------'
Rates: lOt per word per Insertion for noncommercial
advertisements; 25< per word for commerc ial advertisements. Rates are net, and no discounts will be
allowed. Copy must b. accompanied by remittance In
full , and must reach the New York omce by the
first of the month preceding the date of ISSUB.
THE AUDIO EXCHANGE h as the largest
selection of n ew and fully g uara nteed used
eq uipment. Catalog of used equipment on request. Audio Exchange, Dept. AE, 159-19 Hillside Ave., Jama ica ;12, N. Y. AXtel 7-7577 ;
367 Mamaroneck Ave. , White Plains, N. Y.,
WH 8-3380; 836 Flatbush Ave., Brooklyn,
N. Y. , BUckminster 2·5300.
HIGH FIDELITY SPEAKERS REPAIRED
Amprite Speaker Service,
70 Vesey St., New York 7, N. Y. BA 7-2580
LOOKING FOR CLEA!" RESPONSE TO 20
CYCLES? Listen to the radically new Racon
"Hi-C" 15" foam-suspension speaker. Racon
Electric Company, Inc. , 1261 Broadway, New
Yo r k 1, N. Y.
ENJOY PLEASANT SURPRISES? Then
write us before you purchase any hi-fi . You 'll
be glad you did. Unusual savings. Key Electronics, 120 Liberty St., New York 6, N. Y.
:WYel'green 4-6071 .
'l.'RADE for new-used AMPEX's Grove
Enterprises, Rosly n, Pa. TUrner 7-4277.
FOR SALE: I-year· old National Criterion
AM-FM stereo tuner, Horizon 5 preamp, Dynakit 4-8-16-ohm, 50-watt amplifier; all for $205
postpaid (cost $315). Kenneth R. Williams,
407 \'1'. Gorham St., Madison 3, Wis.
W A!"TED: Cook 5B or 5C head or entire
system ; FOR SALE: Rek-O·Kut M-12 lathe
and T-12 turntable. Foran, 3452 N. Hackett,
Milwaukee 11, vVisconsin.
SPEAKER CABINETS
Manufacturer's over-run, brand name enclos ures, genuine mahogany, completely finish ed,
with or without speakers. 50 % off audiophile
list. Write fo r d etails. Custom Craft, P. O.
Box 304, Jasper, Indiana.
AMPEX 350 console, ~85 0, a lso include
portable cases. Excellent condition, h as had
little use. R. J . Entringer, 2211 Camino Del
Reposo, La Jolla, California.
TAPE RENTALS! Wide selection of stereo
and monaural pre-recorded tapes available at
lowest r entals, no member ship f ees. For f ull
details a nd free price li st, write NATIONAL
RENT-A-TAPE, Dept. A, P. O. Box I ,
Winnetka, Ill.
TAPE A!"D DISC DUPLICATING
Write for prices and available services.
MERLE ENTERPRISES, Box 145, Lombard ,
Ill.
" ' RITE for confidential money saving prices
on your HI-Fidelity amplifiers, tuners, tape
recorders. Individual quotations only; no
catalogs. Classified Camera, Dept. A, 2057
Coney I sland Ave., Brookl yn, N. Y.
WANTED: Presto R C-10·14 Or PB-10-H
T ape Mecbanisms, Altec 603B Loudspeakers.
State price and serial number or if interested
in trade for other profession al or hi -fi eqnipment. MASQUE, 331 Vi' . 51st St., New York
19, N. Y.
HI-FI·HAVEN-New J e rsey's leading sonnd
center. Write for information on unique mail
order plan that offers profeSSional advice and
low prices. "Awarded Institute of High Fidelity Manufacturers' Plaque as registered component dealer." 28 Easton Ave., New BrunswiCk, N. J.
WANTED : Western Electric 755A loud speaker. FOR SALE: Antique Victor Tal king
Macbine E lectrola. Robert L angevin, 261;1
Elmdale P lace, Palo Alto, California .
FOR SALE: AMPEX 620 speaker, $125.
Ampex case for 350 tape transport, $50. Seven
10 ,;"" plexiglass, 14 aluminum empty reels , $1
each . Fentone 350A cartridge, $10. Altec
N-3000B crossover, $15. Shipped prepaid and
insnred. M. E . Boyd, 903 Salmon Drive, Dallas,
Texas.
NEW low-distortion PRE-preamp. Transistorized fo r use with low·level cartridges,
$8. See May AUDIO for specs or write. Vic
P itre, 3216 Barker Ave., Bronx, N . Y.
AUDIO
•
JULY, 1958
PROFESSIONAL
DIRECTORY
HIGH -FIDELITY HOUSE
Most complete stock of Audio
components in the West
Phone: RYan 1-8171
536 S. Fair Oaks, Pasadena I, Calif.
Circle 55C
Get more FM stations with the world's most
powerful FM Vagi Antenna systems.
Send 25" for booklet " Theme And Varia .
tions" containing FM Station Directory.
APPARATUS DEVELOPMENT CO.
Wethersfield 9, Connecticut
Circle 55D
CANADA
High Fidelity Equipment
Complete Lines •
Complete Service
Hi- Fi Records - Components
and Accessories
GLECTRO~UOICE
SOUND SYSTEMS
141 DDt'lDAS' $T: WE:ST: TORONTO , CANADA
Circle 55E
SOUND
CORPORAT I ON
Circle 55F
U. S. Depa.rtment of COllUll.erCe h as
i ss u ed a r e po r t w h ic h lists H ig h Fidelity
a s o n e of f our indus tries w hic h a r e "recess ion p r o of" .. . B ear i ng ou t t h e D. of C.
bu lle tin, British Industries Corporation
r e p orts sales a nd ear n ings f or the fir s t
q u a r te r of 19 58 as hig h es t in the com pa n y' s hi s t or y-2 9 p e r cent g r ea t e r t h a n
a y ear ago .. . Ster eo, both t a p e a nd disc,
dom i nate d the a nnua l EIA electroni cs
pa rt s s h ow in Chi cago . Equipm e n t m a nuf ac t u r e r s a r e a lm ost una min o u s in the ir
b eli ef t h at a v a ila bi li t y of r eco rds w ill
b r i ng t h e m a r k e t f or a m plifie rs, cartri dges, s p ea k e rs, e t c., t o b oom p r op or t ion s . Ma j or r ecord co mpa n ie s h ave a nnO Ull ce d p la n s t o r elease s t e r eo d iscs b y
t h e hu nd red s com e Ju ly a nd A u g n s t. S o
th e r e .
S p eakin g of ste r eo , t h e A u g u s t i s s u e of
A UDIO wi ll b e t h e m os t compl e t e c ompila t ion of ste r eo i n fo rm ati on e v e r assemb l ed
b e t wee n t\V O c ov e r s . A n a ll- s t e r e o i ss u e,
it will cover t h e s ubj ect fro m a ll as p ects.
Of pa r ti c ul a r, if n ot r evol u tion a r y , i n t e r est
w ill b e a n a rticle b y B enja m i n B. Bau er,
v i ce- presid e nt of CBS La.bo·r atories, whi c h
w ill d escri b e a m ean s of a c h iev ing s t e r eo
r e prod u c t i on f r o m a s in g le, fai r ly con v e n tion a l, am plifi e r .
Livingston Audio Products Corpora.tion
h a s b een n a me d n ation a l d istr ib u t or for
Counterpo·i nt ster eo tap es ... Allied Radio
Corpora.tion, Chi cago, will b egin m ailing
its g e n e r a l catalog No. 180 t o c u s t om e r s
i n Se ptemb e r . . . Ampe·x Audio h a s b egu n
s h i p m e n t of a conver s ion k i t fo r co n v e rting Ampex h om e m u s ic sys t e m s to 4- track
ste r e o op e ration . T h e assem b ly e n a b les t h e
musi c l ov er to play eith e r t h e n e w 4- t r ack
t a p es or reg ul a r 2- track tape s a t t h e
s impl e fl ick of a l eve r . . . . S p eak e r s a t
the fir s t ann u al di strib u tio n con gress s pon s ored b y t h e Magnetic Recording Industry
Associa.tion i nclu d ed: Nat W el c h , ORRa dio
I ndu stri es, I n c. ; Ed A lts hul er , MIRA; P h il
G undy a nd C. D . D u BOis , Amp ex A u d io;
I r vi n g R ossman, Pe n t r on Co rpora tion ;
Ma nn;
Qu i nn Pri tch a r d , P ritch a rd &
M a rti n So low a n d Adria n P rice, W ex t on
C ompa ny, In c., a nd T om D e mpse y, R eeves
S o un d c r af t Corp or a ti on .
P r e li m i n a r y n egotia t ion s have b een comple t e d fo r t h e p u r c hase of Westrex Corpora.tion, a w h olly - own e d s ub s idia r y of
Western Ele ctric Company, by Litton Inclustries, Inc .. .. Genera.l Cement Manufact1ll'ing- Ccmpa.ny , a d iv is ion of Textron,
Inc., h as purc h ase d t h e America.n Microphone Division of Elgin Na.tiona.1 Wa,t ch
ConlI:a.n y . . . Electro-Acoustic Engi.neers
and Consultants, 82/83 N ew Bon d St.,
L o ndon W .l. h as b een a ppointe d sole
U nite d Kin g d om dis tri butor s fo r Altec
L a.nsing COl'Jlol'a.tion a nd Sta.ncll Hoffma.n
Corporation.
AN EYE FOR VALUE?
Write us your hi.fi needs now
-you'll be elad Y OIl did.
Immediate replies.
Complete stock.
Dept. K2
KEY ELECTRONICS CO.
120 LIBERTY ST., N. Y. 6, N. Y.
Phone: EVergr"n 4-6071
Circle 55e
EMPLOYMENT
HEATH COMPANY's expand ing Audio p rogram calls fo r several exper ienced audio en g in ee rS. Require ments a re a minimum of fi ve
yea rs' des ign experien ce wi t h power a m plifier s,
preamplifier s, AM a n d FM t u ners, and electromechani cal dev ices related to audio. Equal
experience in all of t h ese fields is not r equired,
but some acq uai ntance with th e total field is
necessa r y. W ri te HEATH COMPA NY, Box
698, Ben ton H a rbor, M ichigan.
A T EXTI LE MILL ope rating weaving m ills
in Paterson, New J ersey, a nd Chi cago H eigh ts,
TIlinois, needs sales representatives for c<!mplete line of woven r ad Io a nd teleVI Sion grIll e
cloth. Liberal straigh t commision basis . Box
CG-l , AUDIO, P . O. Box 629, Mineola, N. Y.
AUDIO
•
JULY, 1958
DON'T
MISS
IT!
The August
ALL-STEREO
ISSUE
On Newsstands and at your Hi-Fi
Dealers on July 30
irish
O R AND
ferro-sheen
Available wherever quality tape is sold.
Circle 55A
For
INTEGRITY
IN MUSIC
"Ther e is nothing fin er
than a StTOmb erg-Carlson"
Amplifiers, pre-amplifiers, tuners, speakers, housings, cabinets
-whatever your need, be sure to
see and hear the StrombergCarlson line. No other line offers
deeper experience, more modern
design, such fl awless performance.
Your dealer is listed in
local "Yellow Pages."
yo~~r
STROMBERG-CARLSON
A DIVISION OF GENERAL DYNAMICS CORPORATION
141 8 N. Goodman Street· Rochester 3, N. Y.
Circle 558
55
NORELCO;resents
ADVERTISING
INDEX
the world's
(]4%.] a·1
finest* I
•
pickup cartridge
Acoust ic Research, Inc. . . . . . .. . . . . . .
All ied Radio Corp. .............. . . .
Apparatus Deve lopment Corporation ..
Audio Bookshel f .... .. ... . . .. . .. . . .
Aud io Devices, Inc . . . . . . . .. .. . . .....
Audio Fidelity, Inc . ... . ... .. . . . . 40,
A ud iogersh Corp. . ....... . •.. . . ... .
Audiospeaker Labo rato ries . .. . .. . . .. •
37
56
55
52
53
41
6
42
Bell T e lephone Laboratories . .... . .. .. 16
Bogen, Dav id Co., A Divis ion of The
Siegler Corporation . . . . . . .... . Cov. II
Bradfo rd Audio Corp. . . . . .. . . . .... .. 4
British Ind ustries Corporation
Facing Page 1, 3
Cl ass ified
51
Write for FREE cataloll of ROBINS'
51
PhOno' and Tape Accessories!
13
56
Ferrodynamics Corporation ... . . . .. .. . 54
Fisher Radio Co rp. ... .. . . . ..... . . . . . 5
Fukuin El ectric (Pioneer ) .. . ... .. .. .. 45
Grado
La borator ies
Six Models from 1.75 to ' 55.00
25
55
Dynaco, Inc. . .. .......• . ..... . . . . .. 45
NORTH AMERICAN PHILIPS CO.,INC.
'High Fidelity Products Division, Dept. 2A7
230 Duffy Avenue, Hicksville, l. I., N. Y.
TAPE SPLICERS
• ROBINS GIBSON GIRL tape splicers
assure you of PROFESSIONAL SPLICES
IN SECONDS! They are th e accep.ted
standard of the professional and Indus·
trial users of recording tape because
of their ease and reliability of
operation and high standards ~f workmanship. The only splicers whIch cut
and trim the splicing ta~e and tape
edges with an indented trim cut,
making THE SPLICE WITH THE
GIBSON GIRL SHAPE.
. . . • . . . . . . . . . . . . . . . . . . . .. 54
EICO ..... . ..... " . . ... . ... . . .... .
Electron ic Applications, Inc. . . ... . .. .
El ectrosonic Labo ratories, Inc . .. . .. . . . .
Electro-Voice, Inc . . . . . . . . . . . Cov. IV,
Electro-Voice Sound Systems ....... . .
Ercona Corporation . . . ..... . .
GIBSON GIRL® ...
. . .... . .. . . . . .... 38
AT DEALERS EVERYYiHERE
~
.~
_ROBINS
INDUSTRIES CORP.
FLUSHING 54
• NEW YORK
CIRCLE 56C
CIRCLE 56A
Heath Company . .. ... . . . ... .... .. 7 - 1 1
Hi gh Fidelity Ho use .. . ... . .. ... .. . . . 55
J ansZen Speakers ( Neshaminy
El ectron ic , Corp.) . . ... . .. . . . ..
47
Key El ectron ics ... .. ....... . . ... . .. 55
Kie rul ff Sound Corporation . . .. . . . . . .. 55
Lansing, J ames B. Sound, Inc . . . . . ..... 48
Leonard Radio, Inc . . . . . . . ........... 44
Mc I ntosh Laborato ries, Inc. . .. • .
27
Miessner Inventions, Inc . . .. . ...
44
North Ame rican Philips Co ., Inc.
56
ORR ad io
H ere's your complete money-savin g guide
to Hi-Fi. O wn a fine custom qua lity Hi-Fi'
music syste m at no m ore than t he cost of
a n ordinary phonograph . See dozens of
ALLIED-Recommended comple te Hi-Fi syst ems, p lus the world's la rgest selection of
components (am plifiers , tuners, cha n gers ,
spea kers , enclos ures a nd accessories).
Wa nt to build-your-own?-see our exclusive Hi-Fi KN I GHT-KITS. For everythin g in
Hi-Fi- for euer ything in E lectronics, get
the FREE 1958 ALLIED Catalog.
I
100 N. Western Ave., Chicago 80, III.
Send FREE 1958 ALLIED Catalog
lVame _______________________________
. .. . • ... . . .. 55
Pickerin g & Company, Inc . . . . Cov. III , 15
Pilot Radio Corporation .•.. . .. . ..... 49
Professiona l Directo ry . . . .. . . . ..
55
Raco n Electric Company , Inc . .
Rad io Corporation of America .
Robins Industries, Corp . .. . ...
Rockbar Corporation . .. . . .. ..
. . . •. ..
. . .. . . .
.. .• .. .
... , . . .
Sherwood Electronic La bora to ries, Inc.
Sonotone Corp. .. .. .. ....•. • . . . . .
Strombe rg-Ca rlson, A Division of
Genera l Dynamics Corporation . . . .
Superscope , Inc. ... •.. ..•........ .
50
31
I!!la!t______
City
Zone___ State _____
same unmatched standards as the Revox 8 .. 36.
When you see its unmatched precision"
instrumentation engineering . . . e x p erie nce
.. 1
. . 54
.. 55
.. 2
. .. .. . . . 33
~c:=:t~_==~
CIRCLE 568
TAPE RECORDERS
Dual Track B-36: $399.00 net
Coming! Stereo Adapter eng ineered '0 the
29
Tung-Sol Aud io Tubes . . . _ . . . ... .. .. . 43
Un ive rs ity Loudspeakers, Inc.
REVox
56
o
U A ddress _____________________________
56
Indust ries , Inc.
heritage oj
Swiss precision
Vik ing of Minneapolis . .•.. • . •. .• . . • • 39
its beautiful, full-toned clean listening
quality . • . you ' ll know why th e experts
acknowledge Revox as the new leader in
high fidelity tape recorders .
3 motors . Speeds 7 X & 3%
I PS . Wow & flutter better
than NARTB sta ndards. 40Write for
12,000 cps + 1, -2 db ; to
15,000 at -3 db. B tubes.
literature
18Ys x ll ){, x 13%".
& name of
ELECTRONIC
your nearest
dealer .
APPLICATIONS, Inc.
194 Richmond Hill Ave.
Stamford, Conn .
CIRCLE 56D
AUD,IO
•
JULY, 1958
(1,
the Electro-Voice t~tany compatible stereo cartridge
stereo's standard!
M odel505 Stereo Control with dualchannel magnetic adapter
Price $11.50 Net
M odel504 single magnetic Adapter
only .. ............ Price $3.60 N et
M odel21 D Stereo Cartridge with
Diamond Stylus . .. Price $19.50 Net
Model21S Stereo Cartridge with
Sapphire Stylus ... . Price $9.90 Net
Model 26DST Stereo Turnover to 78
Monaural,. Diamond and Sapphire
Price $22.50 Net
M odel26ST Stereo Turnover to 78
Monaural, Two Sapphires
.
Price $12.90 N et
Good stereo depends on these vital features: Range Response: 20-16,000 cps
:t 214 db to RIAA; Distortion: Less
than 2%; Channel Isolation: 20 db;
Vertical Rumble Rejection: 15 db with
5 meg input; Elements: dual ceram£c,
(lead-zircomum titanate); Weight: 21D
2.4 grams, 26DST 2.6 grams; Tracking
Force: 6 grams; S tylus: 21D-standard
.7 mil diamond; 26DST-standard .7
mil diamond-standard 3 mil sapphire;
Vertical Compliance: 2 x 10.6 em/dyne;
Lateral Compliance: 2 x 10.6 em/dyne;
.output: .5 Volt RM$ from Westrex
standard RIAA T est R ecord; Capacity:
500 mmfd per element for stereo; 1000
mmfd paralleled for monaural; M ounting: EIA (RETMA) standard W' and
7/16" centers; R ecommended Amplifier Input Impedance: 5 megohms or
higher.
Thousands being installed as original equipment attest to industry acceptance; thousands in use prove its unquestioned superiority for monaural as well as stereo. The E-V Stereo Cartridge uses a .7 mil replaceable stylus and dual
high fidelity ceramic elements so essential to the exacting deinan~s of stereo reproduction. Pickup from stray magnetic
fields is non-existent, hum and rumbL are far below the level eli even tee most e\'pensivs magnetic cal'tdd g,",S, :md
PZT ceramic elements deliver a precise RIAA curve. The E-V Stereo Cartridges exclusive Rumble Suppressor
(pat. pend.) virtually elimirl:ates vertical turntable rumble without degrading full frequency response range of the
cartridge . . . allows you to use it with any turntable or record changer. Totally Cc;.mpatible ... for stereo, it's superb;
for monaural ... it's superior to even your present cartridge.
THE FIRST STEP TO STEREO. Many fine monaural cartridges are too "stiff" to play stereo records with-
out seriously damaging them; therefore, if you replace your present cartridge with the new E-V Compatible Stereo
Cartridge, you may continue playing your present library of LP's plus all the new stereo records monaurally.
THE SECOND STEP TO STEREO. Connect the E-V Stereo Cartridge leads 10 the 505 Stereo Control Center
(net $11.50). You can then select from "monaural," "stereo," or "channel reverse" for easy balancing. The 505 also
converts your magnetic input to high impedance ceramic input, if required. Run one lead to your present high fidelity
system, run Cthe second channel lead to a second amplifier (and speaker). NOTE: The E-V Stereo Cartridge is corrected for RIAA curve, doesn't need the equalization of a second preamplifier.
If you do not plan to purchase a second amplifier and speaker now, you can still get stereo by running the second
channel lead through the 505 to your radio or TV set phono input. You can improve your system later by Slnlpl~'II'
adding a second amplifier and speaker. Stereo records are available now. Why wait? Enjoy the vivid reality of
phonic sound today. Whether you're purchasing your first system or converting now, use the Electro-""'''''''JI
patible Stereo Cartridge. See your high fidelity dealer, or write Electro-Voice for free booklet on choosing
equipment, and a special Stereo Demonstration Record ($1.50 prepaid) .
ELECTRO-VOICE, INC.
BUCHANAN. MICHIGAN
FOREMOST IN ELECTRO-ACOUSTICS- High Fidelity Loudsp eakers and Rn"los.ure:"
Microphones and Public Address Speakers. Marine Instruments. EVI Professional Electronic
ADD - ON
STEREON-THE
UNIQU E
ELECTRO-VOICE
CONCEPT THAT
ELIMINATES
THE
NEED
FOR
A
SECO ND
FULL - RANGE
SPEAKER .
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