Eico HF-81 User manual

general description
MODEL Hf -
DUAL 14 WATT HI-
STEREO AMP - PREAMP
GENERAL
The EICO Model HF-81 is a complete high fidelity stereo-
phonic control center and a pair of 14watt amplifiers, all
on one chassis. With it you can select preamplify, and
control accurately any stereophonic source (tape, discs, or
broadcasts) and feed it through the self-contained dual 14
watt amplifiers to a stereo pair of speaker systems. When
you playa monophonic source, the 14 watts available per
channe I adds up to a total of 28 watts for your two speaker
systems. If you desire, both amplifiers can be connected
in parallel and driven byone preamp I ifier-control section
whi Ie the other preampl ifier-control section is free to drive
an external power amplifier. In this way your old ampli-
fier can be put to use in a stereophonic system. Construc-
tion is of the "Iow silhouette" type that permits you to
dispense with cabinetry if desired.
FEATURES
1. Separate low level input in each channel for mag.
phono, tape head, and microphone. Circuitry carefully
designed to provide the high gain required by tape heads
and high quality, low output mag. cartridges without hum
and noise problems. A front panel switch permits choice
of the proper NARTS tape head equalization for either
7 1/2 & 15 or 3 3/4ips tape speeds.
2. Separate high level inputs for AM, FM, and FM
Multiplex. Also two auxiliary A inputs (one in each
channel) and two auxil iary B inputs (one in each channel).
Input Selector switch on front panel has positions for feed-
ing FM tuner output to one channel and AM tuner to
other, or FM tuner to one channel and FM Multiplex
adapter output to other.
3. May be used as either two independent amplifier-
preamplifiers,or one preamplifier-control section may be
set free to operate an external power amplifier and the
other preampl ifjer-control section used to drive both in-
ternal power ampl ifiers connected in parallel at the
speaker connection terminals. A top - of-chassis sl ide
switch permits choice of operation.
4. Ganged level controls and a separate focus (balance)
control.
5. Independent full-range bass and treble tone controls
in each channel. Tone controls of the low distortion
variable cross-over feedback type.
6. Identical Williamson type, push-pull EL84power am-
plifiers with high quality output transformers.
7. Hum balance control, panel-mounted fuse, pi lot lamp,
convenience outlets.
8. EICO " low silhouette" construction employing hori-
zontal chassis for proper layout and component separation.
Easy console installation, if desired, with complete shield-
ing and adapatability to any panel thickness.
Copy,;ght I1d 1958 Electronic Instrument Company, Inc.

SPECIFICATIONS *
Output Power: 28 watts continuous; 56 watts peak.
1M Distortion (60c &7kc at 4: : 2% at 28 watts; 0.
at 10 watts.
Frequency Response: (2w):I:O. 5db 10c to 1O0kc.
HarmonicDistortion: 16 watts at less than 1% 30c to lOkc;
20 watts at I ess than 1 % 40 c to 10 kc; 28 watts at
less than 1% 50c to 5kc; 8. 4 watts at less than
2% at 20c.
Transient Response : excellent square wave reproduction
(4usec rise time) negligible ringing, rapid settl ing
on 10kc square wave.
Transient Distortion (60cps tone burst) less than 1% at
fu II power.
Inverse Feedback: 20db
Stability Margin: 12db
Damping Factor: above 8, 20 cps - 15 kc.
Sensitivity (input for rated output): mag. phono 4mv;
tape head 7. 5 ips - 2 mv; tape head 3. 75 ips
5mv; mic - 6mv; tuners, auxiliaries - 0. 5V.
** Hum & Noise Level (below rated output): mag. phono
60db; tape head - 51 db; mic - 57 db; tuners, aux-
iI iaries - 75 db.
Tone Control Range: ::I:15db at 50c and 10kc.
Speaker Connections: 4 8, and 16 ohms.
Tubes: 4 - ECC83/12AX7, 2 - ECC82/12AU7, 4- EL84,
2 - EZ81.
Size: 15" wide, 4 3/4" high, 10 1/2" deep.
Weight: 241bs.
* Where power output is involved, figures are given for
two channels combined; divide power output figures by
two for specifications of each channel alone. Design
property specifications refer, of course, to either or both
channels.
** Measured with tone controls set "flat", LEVEL control
maximum, and FOCUS control set for maximum gain in
channe I checked.

mechanical installation
GENERAL
a) HEAT DISSIPATION (VENTILATION): In common with
other electronic equipment, the HF-Sl produces consider-
able heat in normal operation. Unless continuous and ade-
quate air flow is obtained around the heat producing ele-
ments, these elements will over-heat and their useful life
will be greatly curtailed.
It is useful to understand the process of convection where-
by heat is removed in judging the suitability of a location.
Air heated by the heat-producing elements expands and
rises; cool air is drawn from beneath to take the place of
the heated air. In this manner, a stream of air is set in
motion which continually removes heat from the ampli-
fier. (In particular, we are mainly concerned with the
major heat-producing elements; the four EL84 output tubes
and the two EZSl rectifier tubes. ) If there is any impedi-
ment to or constriction of the airflow, the essential process
of heat removal will be adversely affected.
Adequate ventilation will be provided if the amplifier is
installed in an open-back console provided that the top
of the amplifier is spaced at least two inches below any
shelf mounted above it. If the cabinet is enclosed at the
rear, provide several large holes or slots as low down and
as high up in the cabinet back as possible. As an alter-
nate, holes may be provided in the sides, bottom, or top
of the cabinet. The important thing to remember is that
effective ventilation requires provision for cool air to en-
ter at the bottom and hot air to leave at the top.
If the amplifier is not installed in a console, it may be
situated on an open surface or on a shelf of a boakcase~
Four rubber feet are also provided so that the amplifier will
not mar the surface of furniture on which it is placed.
b) EASY ACCESS TO CONTROLS: Mount the amplifier
at a height which will permit easy manipulation of the con-
trols. Tuner controls should be located nearby.
c) ACCESSIBILITY TO PARTS: . Tubes are the most fre-
quently replaced items in electronic equipment. If the
amplifier is installed in a console, sufficient space should
be alloted to reach and remove any tube in the amplifier.
Furthermore, input and output terminals of the ampl ifier
should be accessible to permit easy interchanging of sys-
tem components for comparison, and connection or dis-
connection of a portable tape recorder which is stored a-
way when not in use. If antennas are strung around the
back of the console in which the amplifier is installed,
arrange them so they will not interfere with access to the
amplifier.
d) ACOUSTICAL ISOLATION: If amplifier and speaker
are installed in the same cabinet (not recommended))' pro-
vide sufficient separation to minimize mechanical speaker
vibration reaching the amplifier. The minimum separation
is about one foat.
CONSOLE MOUNTING
a) 0 erationsonconsolefront anel reliminar to am li-
fier mounting: Tape the panel template provided to
the face of the console so that the top of the mounting sur-
face line on the template is level with the top of the
amplifier mounting shelf. Note: When shelf is not avail-
able, tape the template atanyconvenientspot on the face
of the console. (2) Use an awl or a nai I to pierce the
centers of the four extreme outer holes for mounting the
control plate, to transfer their locations to the console
panel beneath. (3) Trace out the rectangular cutout with
an awl or nail and then pierce the centers of the four 1/2"
holes)' one in each corner of the cutout. (4) Remove the
panel template. (5) Drill the four 1/2" holes in the con-
sole panel, one in each corner of the rectangular cutout
area. Cut out the rectangular piece with a keyhole sawl
using the four 1/2" holes as starting holes.
b) Am lifier mounting in console: (1) Pull off the control
knobs. 2 Remove the four screws that fasten the bezel
to the side pieces and remove the bezel. (3) Remove the
two screws and nuts that fasten the control plate to the
bezel. The bezel is not used in console mounting. ~)
Fasten the control plate to the console panel with the two
#4x3/S wood screws supplied. (5) If the rubber feet have
been inserted irwhe bottom plate, remove them. (They may
be pried out with a thin screwdriver. ) (6) Place the unit -
on the mounting shelf and slide it forward until the slide
switch sl,lpport bracket is up against the panel and the
slide switch accessible from the front; the control shafts
should be approximately centered in the corresponding
holes in the control plate. (7) With a sharp penci!l draw
the outline of the side and rear bottom edges on the chassis
shelf. As the bottom plate falls short of the full width by
3/16" on each side, draw new side edge lines 3/16" in-
side the original side edge lines. (S) Now remove the
knobs and take the chassis off the shelf. (9) Remove the
6screws which fasten the bottom plate to the chassis. (10)
Place the bottom plate exactly in the outl ine drawn on the
shelf and mark the position of the center hole on the left
side and the center hole on the right side. (11) Remove
the bottom plate and dril! each of the marked holes on the
shelf to a diameter of 1/4" (12) Refasten the bottom
plate to the chassisl withthefourof the six #8x3/Sscrews
previously removed, using the two holes at the rear and the
two holes at the front of the chassis. (13) Replace the
chassis on the shelfl positioning it exactly in the outline
previously drawn, and restore the knobs. This time make
sure that the indicator dot on each knob agrees with the
control position. (14) From the bottom side of the shelf
insert a #S xl" screw, with a 1/2" flat washer against
the head, through both the left and right side center holes.
These screws engage the stamped nut over each hole on
the chassis flange and when tightened secure the chassis
to the shelf.

electrical installation
The HF-81 can be used in two ways for a stereophonic
system. In all cases, plug monophonic sources and one
track of monophonic/stereophonic sources in the channel
1 inputs; plug the other track of stereo sources in the chan-
nel 2 inputs. It is assumed in what follows that a stereo-
phonic phono cartridge is being used. Monophonic phono
refers to playback of a monophonic recording with a stereo-
phonic cartridge.
CH.
32 16 8
CH.
32
(J) (J) (f)
(j)
(J)
(j) (j)
TO MATCHING
TAP TO MATCHING
TAP
a) INTERNAL POWER AMPLIFIERS OPERATED SEPARATE-
LY, EACH DRIVING ONE SPEAKER OF A STEREO PAIR.
This arrangement is used when there is no other amplifier
the user desires to include in the system. The SERVICE
SEL. sl ide switch on top of the chassis must be set to SEP-
arate. Signal connections are all internal, so only the
speaker connection need to shown (Fig. la, rear chassis
view). The internal arrangement ion in the HF-81 at each
of the positions of the FUNCTION selector are shown in
Figs. Ib, lc, Id, Ie, If, and 19, as an aid to understand-
ing the operation with this arrangement.
SPKR. SPKR.
FIG. la. SPEAKER CONNECTIONS
FIG.
CHECK AMPL. 1 CH. I LOW
LEVEL INPUTS
CH. 1 HIGH CH. 1
LEVEL INPUTS TAPE OUT
IPREAMP~
CH. CH. POWER AMP SPEAKER
CH. CH.
FIG.
CHECK AMPL. 2
CH. 2 LOW
LEVEL INPUTS PREAMP
CH. CH.
CH. 2HIGH CH.
LEVEL INPUTS T APE OUT
POWER AMP SPEAKER
CH. CH.
CH. 1 HIGH
LEVEL INPUTS CH.
TAPE OUT
CH. 1 LOW
LEVEL INPUTS
SPEAKER
CH.
FIG. Id
STEREO NORMAL
CH. 2 LOW
LEVEL INPUTS
SERVICE SEL.
~:'~P
~~
SEP ..
I PO
;~.
AMP ~~~~R
CH. 2 HIGH CH.
LEVEL INPUTS TAPE OUT
CH. 1 HIGH
LEVEL INPUTS CH.
TAPE OUT
CH. 2 LOW
LEVEL INPUTS
SPEAKER
CH.
CH. 1 LOW
LEVEL INPUTS
FIG. Ie
STEREO REVERSE
SEP SPEAKER
CH.
CH. 2 HIGH
LEVEL INPUTS CH.
TAPE OUT

b) INTERNAL POWER AMPLIFIERS COMBINED (TIED
TOGETHER AT THE INPUTS AND PARALLELED AT THE
OUTPUTS) TO DRIVE ONE SPEAKER OF A STEREO PAIR.
This arrangement is employedwhen the useralready has a
high quality amplifier (usually 20watts or more if it is to
be worthwhile) which he desire to include in the system.
The preamp-tone control combination including the reg-
ular CHI tone control feeds the combined internal power
amplifiers; the preamp-tone control combination including
the regular CH2 tone control feeds out through the CH2
TAPE OUT jack to an external power amplifier. The SER-
VICE SELECTOR switch on the chassis must be set at the
COMbined position for this service in order to disconnect
the input of the CH2 power amplifier from the output of
the CH2 tone control and connects it instead to the input
of the CHl power amplifier, The CHI and CH2 power
amplifiers are paralleled at the outputs, as shown, by an
external jumper connected between corresponding speaker
connection taps, The external signal connection and the
speaker connections are shown in Fig, 2a. The internal
arrangements in the HF-81 at each of the positions of the
FUNCTION selector are shown in Figs. 2b, 2c, 2d, 2e,
, and 2g, as an aid to understanding the operation with
this arrangement.
CH. 1 LOW
LEVEL INPUTS
FIG.
MONOPHONIC TUNER,
TAPE, TV
CH. 1 LOW
LEVEL INPUTS
FIG. Ig
MONOPHONIC PHONO
CH. 2 LOW
LEVEL INPUTS
CH. 1 LOW
LEVEL INPUTS
FIG.
CHECK AMPL.
CH. 1 HIGH
LEVEL INPUTS CH.
TAPE OUT
SEP
CH.
TAPE OUT
CH. 1 HIGH
LEVEL INPUTS CH.
T APE OUT
SERVICE SEL
SEP ~~~:MP
CH. 2HIGH CH.
LEVEL INPUTS T APE OUT
TAPE
OUT CH.
~--~---~----
(f)
. I
::! I
:Q it
'"
'" I
a I
"" I
'"
EXT~RNA BASIC
--- '
POWER AMPLIFIER ~ i
~ '
~ I
1___-
.INPUT
SPEAKER
CH 1
SPEAKER
CH.
SPEAKER
CH.
SPEAKER
CH.
CH.
* On integrated amplifiers HF20, HF32 feed into TAPE
OUTPUT lack; on HF521 feed into ELECTRONIC CROSS-
OVER INPUT jack, after severing connection between
ELECTRONIC CROSSOVER IN and OUT jacks.
FIG. 2a. SPEAKER & EXTERNAL
SIGNAL CONNECTIONs.
CH. 1 HIGH
LEVEL INPUTS CH. TAPE OUT
SPEAKER
CH.

FIG.
CHECK AMPL. 2
FIG.
STEREO NORMAL
FIG.
STEREO REVERSE
FIG.
MONOPHONIC TUNER,
T APE,
CH. 2 LOW
LEVEL INPUTS
CH. I LOW
LEVEL INPUTS
CH. 2 LOW
LEVEL INPUTS
CH. I LOW
LEVEL INPUTS
CH. 2 LOW
LEVEL INPUTS
CH. I LOW
LEVEL INPUTS
CH. 2 HIGH
LEVEL INPUTS CH.
TAPE OUT
CH. I HIGH
LEVEL INPUTS CH.
TAPE OUT
CH. 2 HIGH
LEVEL INPUTS CH.
TAPE OUT
CH. 2 HIGH
LEVEL INPUTS CH.
TAPE OUT
CH. I HIGH
LEVEL INPUTS
CH.
TAPE OUT
SPEAKER
CH.
SPEAKER
CH.
SPEAKER
CH.
SPEAKER
CH.
SPEAKER
CH.
SPEAKER
CH.
SPEAKER
CH.

CH. l HIGH
LEVEL INPUTS CH. T APE OUT
CH. 1 LOW
LEVEL INPUTS
FIG.
MONOPHONIC PHONO SPEAKER
CH.
CH. 2 LOW
LEVEL INPUTS
COM
CH. 2 HIGH
LEVEL INPUTS CH.
T APE OUT
c) INPUTS: There are identical pairs of MAG. PHONO,
TAPE HEAD MICROPHONE, AUXILIARY A, and AUX-
ILIARY B inputs -one of each pair in channell and chan-
nel 2 - and each is identified accordingly by the suffix
1 or 2. The MAG. PHONO, TAPE HEAD, and MICRO-
PHONE pairs of inputs are all II low level" inputs, mean-
ing that they all feed through a preamplifier/equalizer
stage in either channel l or 2. The AUXILIARY A and
AUXILIARY Bpairsofinputs are high level" inputs, mean-
ing that they enter either channel l or 2 at a point after
the preampl ifier/equalizer stages. The AM, FM and FM-
FM Multiplex inputs are also "high level inputs , which
are internally selected in pairs - one for each channel
- by the INPUT SEL. switch. At the MONAURAL posi-
tion of the FUNCTION SEL., AM only is selected at the
AM-FMposition of the INPUT SEL., and FMonlyis select-
ed at the FM - FM MULTI. position of the INPUT SEL.
l) MAG. PHONO 1, MAG. PHONO 2: These inputs
are intended for the two outputs of a stereo magneti c car-
tridge, or for a stereo ceramic cartridge with adaptors.
The correct method for wiring a three terminal cartridge
is shown in Fig. 3. If the cartridge is a four terminal
type)' short the two inside terminals of the cartridge to-
gether and treat it exactly as if it were the single center
terminal shown in Fig. 3. The loading presented to each
output of the cartridge by each MAG. PHONO input is
100,000 ohms. If a lower loading resistance is required
by the particular cartridge used, connect a shunt resistor
of appropriate value from each outside terminal of the car-
tridge to the center (common) terminal. This can be done
actually by mounting a 3-post terminal strip on the under-
side of the phonograph mounting board at a point near the
lead break-out from the pickup arm. These shunt resistors
are then wired to this terminal strip as shown in Fig. 3.
The value of each of the two shunt resistors (Rs) can be
determined from the desired loading resistance (RI) by this
formula Rs = 100,000 x RI ohms
00)' - RI
or th is tabl e; for RI = 50KQ, use Rs = 1 OOKQ; for RI :: 33KQ,
use Rs = 50KQ; for RI = 25KQ, use Rs = 33KQ.
SPEAKER
CH.
* NOTE: All ceramic cartridge manufacturers have devel-
oped simple networks which when connected the outputs
of their cartridges result in a characteristic identical to
that of magnetic cartridges. By interposing the recom-
mended adaptor for the particular ceramic cartridge be-
tween the cartridge outputs and the MAG. PHONO in-
puts of the ampl ifjer, it is possible to use the MAG. PHONO
inputs for the ceramic cartridge with excellent results.
Adaptor networks are given in the literature for the par-
ticular ceramic cartridge and can be built on a terminal
strip mounted on the underside of the phonograph base, or
may be available in convenient component form from the
cartridge manufacturer. Stereophonic crystal cartridges
(Ronette "Binofluid II OV and BF40) can be connected di-
rectly to auxiliary high level inputs.
2) TAPE HEAD 1, TAPE HEAD 2: These inputs are in-
tended for direct connection to the two outputs of a stereo
tape playback head. A front panel slide switch permits
choice of NARTB tape head equalization either for71/2
(& 15) ips or3 314 ips tape speeds. The loading resistance
presented by each tape head input is 100,000 ohms.
3) MICROPHONE 1, MICROPHONE 2: These inputs are
intended for rec~~:ving the output signals directly from
two separate microphones. It is preferable that the micro-
phones used be of the high impedance type.
4) AUXILIARY AI, AUXILIARY A2: These inputs are
intended for either a stereophonic or monophonic high
level source. A stereophonic high level source might be
a stereo tape deck with built-in playback equal ization
for both tracks. A monophonic high level source might
be a monophonic crystal cartridge or tv sound. Plug a
monophonic source intoAUXJLlARY A 1, leaving theAUX-
ILIARY A2 input unused. Note that the input impedance
at all these high level inputs is 0. 5 megohm, which is too
low for ceramic cartridges requiring 2 to 3 megohms in-
put impedance. For ceramic cartridges, use the MAG.
PHONO inputs with the simple adaptor networks recom-
mended by the manufacturers. For stereophonic crystal
cartridges (Ronette "Binofluid" OVturnover and BF40 sin-
gle needle), the 0. 5 megohm load provided at the high
level inputs is exactly the loading impedance required.

TO INPUT
HF 81
. .
OF STEREO
TAPE RECORDER
OUT
cgJ -=8
STEREO MAG.
CARTRIDGE
FIG. 3
5) AUXILIARY Bl, AUXILIARY B2: Same as for AUX-
ILIARY A 1, AUXILIARY A2 above.
6) AM: This input is intended for AM tuner or the AM
output of an FM-AM tuner where the FM and AM sections
are independent.
7) FM: This input is intended for an FMor FM-AM tuner
where the FM and AM sections are independent.
8) FM MULTIPLEX: This input is intended to receive the
output from an FM Multiplex adaptor.
NOTE: A shielded cable with a shielded "phono-type
plug should be used to connect from each of the above-
.-- , .
2 - PHONO RECEPTACLE
STRIP FIG. 4
e) POWER CONNECTIONS: The line cord of the HF-
must be plugged into a house outlet providing normally
117 volts, 60 cycles AC power. A convenience recep-
tacle on the rear chassis can be used, if desired, with a
cube tape to provide 117VAC power to the associated
equipment. This convenience receptacle is not switched
or fused and provides 117VAC at all time'S""rregardless
of whether the HF-81 is turned on or off.
HUM ADJUSTMENT
After checking the ampl ifier for proper operation, remove
all input cables to the amplifier and make the following
control settings which hold throughout the process of hum
adJustment: INPUT SELECTOR at PHONO, FUNCTION
SELECTOR at STEREO, FOCUS control at 0, LEVEL con-
trol at 10)' both TREBLE controls at -5, both BASS controls
at 0; the two speaker systems must be in phase and placed
near one another for this adJustment. Next, procede
y~~
TO MAG. INPUT
,--
TO MAG. INPUT 2
mentioned sources to the correspondmg amplifier input
jack. Unless the source has a low-impedance output such
as a cathode follower (with which up to 50ft. of cable
can be used), use the shortest possible connection and
low - capacity shielded cable (cable having as low as
25mmfd capacitance per foot is available).
d) TAPE OUTPUT 1, TAPE OUTPUT 2: When no external
amplifier is used in the system, both these outputs are
available for feeding out to a stereo recorder. When an
external power ampl ifier is used in the system, TAPE OUT-
PUT 2 is used to feed out to the external power amplifier.
If it is desired to do stereo recording under the latter
conditions, construct a device such as shown in Fig. 4.
Use low capacity shielded cable for connections.
TO INPUT 2
OF STEREO
RECORDER
TO EXTERNAL
POWER AMPLIFIER
6 ,
follows: With your ear held close to the speakers, insert
the amplifier power plug into the wall outlet and listen
to the hum level. Now pull out the plug and re-insert it
with the prongs reversed. Choose the prong position with
the least hum. Now connect the tuner input connector to
the amplifier input jack, and with the tuner set between
stations and the tuner volume control set at a minimum, do
the same with the power plug of the tuner; use either the
117VAC receptacle on the HF-81 or one receptacle of a
cube tap inserted in the 117V AC receptacle on the HF-81.
Next)' connect the phono cartridge leads to the MAG.
PHONO 1 and 2 inputs, and, with turntable off and pick-
up arm at the rest position, find the insertion position of
the turntable line cord plug that yields lowest hum. Fin-
ally, connect the tape head leads to the TAPE HEAD
and 2 inputs, and, with the tape deck turned offl find the
insertion position of the tape deck line cord plug that re-
sults in lowest hum. When all of this is completed, ad-
just the hum balance control on top of the amplifier chassis
for least hum.

operation
PRELIMINARY: Be sure all tubes are firmly seated in their
sockets and that the tube shields are making good contact
with their baSes. As initial adjustments, set these controls
as follows: LEVEL at 0, FOCUS at 0)' both BASS controls
at O. Turn the amplifier on by turning the TREBLE 2 con-
trol clockwise from AC OFF and set it at zero initially.
Also set the TREBLE 1 control at zero. Please note that
in the instructions that follow, it is assumed that a stereo
pick-up and/or a stereo tape head is being employed in
the system.
LISTEN IN G TO PHONOGRAPH: Set the IN PUT SELEC-
TOR to PHONO if you have a megnetic cartridge or a
ceramic cartridge with adaptors interposed between the
cartridge outputs and the MAG. PHONO 1 and 2 inputs.
(The RIAA equalization provided at the PHONOposition
is now the international standard in the recording industry
for both monophonic and stereophonic records and is also
a very good compromise for the most important of the older
monophonic recording characteristics. ) Set the INPUT
SELECTOR to AUX Aor AUX B if you are using a stereo-
phonic crystal cartridge (Ronette) connected to eitherAUX
A or AUX B inputs. Set the FUNCTION SELECTOR at
either STEREO position. To balance levels between the
channels, playa conventional monophonic (lateral) re-
cording on the changer or turntable and turn the LEVEL
control up until you have normal listening level. Note
that the action of the FOCUS control (sometimes called a
balance" control) is to simultaneously raise the level in
one channel while lowering the level in the other as it is
turned in anyone direction. At the zero setting of the
FOCUS control)' equal sound volumes would obtain on both
channels only if the ideal conditions of identically effi-
cient loudspeakers and identical overall gains in both
channels existed. With the conventional monophonic re-
cording being played, adjust the FOCUS control for equal
volume from each speaker system. With the FOCUS set-
ting properly made, any stereo recording played back will
have close to the same balance as actually exists in the
recording. The FOCUS control setting can be a semi-per-
manent adjustment in that, at any given time, the setting
achieved as described above will usually be satisfactory
for tape stereo, and may also be for broadcast stereo, if
it means exist of adjusting for equal output levels from the
stereo broadcast rece iving equ ipment. As components age,
a shift of the normal FOCUS control setting may be nec-
essary. Note that there are a concentricpairofbass con-
trois, one in each channel and a concentric pair of treble
controls, one in each channel. Use the separate bass and
treble controls to compensate for any audible deviation
of the recording from the standard recording characteristic,
as well as to compensate for the over-all characteristics
of your audio system (including room acoustics). Set the
FUNCTION SELECTOR to STEREO NORMAL or STEREO
REVERSE for stereophonic records and to MONOPHONIC
PHON 0 for CONVENTIONAL MON OPHON IC records.
LISTENING TO TAPE DECK (direct connection to tape
head): Set the INPUT SELECTOR to TAPE. NARTB tape
head equalization is provided in both channels for the
tape speed selected with the TAPE switch on the front
~nel'- One position is for71/2and 15ips tapes and the
other for 3 3/4 ips tapes. These equalizations are the
industry standard for pre-recorded stereophon i c and mono-
phonic tapes. If the FOCUS' control has been set as
described in the preceding paragraph, it will usually be
satisfactory for this function also. Otherwise, it may be
set in a similar manner using a test tape or simply by ear.
Set the FUNCTION SELECTOR to STEREO NORMAL
REVERSE for stereophonic tapes or to MONOPHONIC
TUNER, AUX for monophonic tapes. Use the BASS and
TREBLE tone controls as described above.
LISTENING TOAMONOPHONIC SOURCE CONNECT-
ED TO AUXILIARY AI, AUXILIARY Bl, TO MONO-
PHONIC AM BROADCAST, OR TO MONOPHONIC FM
BROADCAST: Set the INPUT SELECTOR to AUX. A,
AUX. , AM-FM, or FM-MUL TI. respectively and the
FUNCT10N SELECTOR to MO~OPHONIC TUNER, AUX.
Use the BASS and TREBLE controls as described previous I y.
LISTENING TO A STEREOPHONIC SOURCE CONNECT-
ED TO AUXILIARY Al and A2, AUXILIARY B1 and B2,
AM and FM, FM and FM MULTIPLEX: Set the INPUT
SELECTOR to AUX A, AUX B, AM-FM, or FM-MUL TI
respectively. Set the FUNCTION SELECTOR at STEREO
NORMAL or STEREO REVERSE. The FOCUS, BASS and
TREBLE controls are set as described previously.
MAKING RECORDINGS: Tape recordings may be made
by connecting the recorder to the TAPE OUTPUT jacks.
See "TAPE OUTPUT 1, TAPE OUTPUT 2" under ELEC-
TRICAL INSTALLATION. Please note that recordings
cannot be made on tape decks unless those decks are
equipped with the electronics required for recording.
FUNCTION SELECTOR: The STEREO NORMAL and STER-
EO REVERSE positions are both used for stereophonic re-
production. At the STEREO REVERSE position, the chan-
nel 1 and channel 2 amplifiers from the tone controls to
the speaker connections are interchanged. These two
positions permit interchanging the signals fed to the two
speakers so that the correct left to right display of the
orchestra can be achieved on all recordings or broadcasts.
The CHECK AMPL. 1 and CHECK AMPL. 2 positions per-
mit hearing either channell alone or channel 2 alone for
comparison or balancing purposes during stereophoni c use.
The MONOPHONIC TUNER, AUX position is used for
monophonic FM, AM, tv sound)' monophonic phono cart-
ridge monophonic pre-amplified tape etc., fed into chan-
nel 1 inputs. At this position)' the channel 2 inputs which
are unused in this type of operation, are disconnected
from the active channel so that they cannot contribute
interference. At the MONOPHONIC PHONO position,
the channell and 2 corresponding inputs are mixed, which
is useful when playing monophonic records with a stereo-
phonic cartridge to cancel vertical rumble components.

BASS CONTROL 1, BASS CONTROL 2 (CONCENTRIC):
The plus sign on the right side of the dial indicates that
clockwise rotation from the mid-point (0) of either control
increases (boosts) _bas~ response; the minus sign on the left
side indicates that counter-clockwise rotation from the
mid-point decreases (cuts) bass response. There is no in-
teraction with the TREBLE control. Start all adjustments
with this control set at the mid-point (0), which is called
the "flat" position since bass response is neither cut nor
boosted at this position.
maintenance
TREBLE CONTROL 1, TREBLE CONTROL 2 (CONCEN-
TRIC): The plus sign on the right side of the dial indicates
that clockwise rotation from the mid-point (0) of either
control increases (boosts) treble response; the minus sign
indicates that counter-clockwise rotation from the mid-
point decreases (cuts) treble response. There is no inter-
action with the BASS control. Start all adjustments with
this control set at the mid-point (0), whi ch is called the
flat" position since treble response is neither cut nor
boosted at this position.
GENERAL
Your amplifiershou Id require I ittle service except for nor-
mal tube replacement. We recommend no substitutions for
the tube types used in this amplifier except as stated. All
the tube types used are distributed national Iy, but replace-
ments can be obtained directly from EICO if desired.
To facil itateservicing, remedial and trouble-shooting pro-
cedures have been provided in the TROUBLE-SHOOTING
CHART that follows. A VOLTAGE AND RESISTANCE
CHART is also provided as an aid in locating defective
components. DC operating voltages are given both at no
signal and signal developing 14 watts output, as well as
the corresponding 1 kc signal voltages.
TROUBLE-SHOOTING PROCEDURES
Connect the leads from the stereo cartridge and from the
two speakers to the amplifier. These connections are made
as described in the section "Electrical Connections " . Set
the Input Selector control at PHONOand the Function Se-
lector at STEREO. Playa known high quality stereo record-
ing on the phonograph. If there is no output to the speaker
of if the output is low or audibly distorted, procede to the
checks for those symptoms. If there is excessive hum in
. the output, disconnect the phono input cable from the
ampl ifier and short the phono input jack to chassis. If the
hum disappears, the trouble is not in the amplif.er but in
the phonograph or in the connection to the amplifier.
each case, check for the trouble in the amplifier which
seems defective. If both amplifiers are defective, check
the power supply.
The cause of phonograph hum may be a metal pick-up arm
not grounded to the cable shield (try a good single ground
connection to the cable shield from turntable frame, pick-
up arm, and cartridge case), direct hum pick-up by the
magnetic cartridge from the record player motor(tryusing
a rubber mat on the turntable to increase the separation of
the pick-up from the motor), or pick-up from a power
transformer or other magnetic field in the vicinity (try
moving phonograph away from suspected source). Check
also that the phono input cable shielding is grounded to
the ampl !fier chassis at one point only, through the skirt
of the input connector where it plugs into the ampl ifier.
Finally, try a good building ground such as a connection
from a cold water pipe terminated under speaker terminal
G" on the amplifier Do not connect such a ground wire
to other components in the system If possible, let each
channel be connected to the amplifier using a separate
shielded cable to the ampl ifier input. It is also desirable
that the ground leads on both cables not be connected to-
gether at any point - not even at the cartridge. How-
ever, with some cartridges, it will not be possible to do
this. In this case, just disregard this last instruction.
Excessive hum on other inputs may be checked in a similar
manner. Disconnect the input cable in question and short
the particular input jack to the chassis. If the hum dis-
appears, the trouble is external to the amp! ifier. Note
that on all inputs, the braid of th;;; input cable shou Id con-
nect to the ampl ifier only through the skirt of the input
connector. The cause and remedies for the following
symptoms are then based on the assumption that checks
made in the manner described above have eliminated the
possibilityof the trouble being external to the amplifier.
If the trouble is no output or low output, check AC signal
voltages and DC operating voltages starting at the input
and work step_by-step toward the output in each ampl i-
fier. Set the VOLUME control to maximum (10), the
FOCUS, BASS and TREBLE controls to their mid-points
(0), the INPUT SELECTOR to PHONO and the FUNC-
TION SELECTOR to STEREO . Use a 1000cycle sine-
wave signal, such as supplied by the EICO 377 Sine &
Square Wave Audio Generator In addition, use a pre-
cision 100: 1 attenuator to permit obtaining a level of
0035 volt fed into MAG. PHONO from an audio gen-
erator output of 0.35 volts, which can easily be measured
onthelowestACvolts range ofyourVTVM (also improves
signal to hum from generator). Use a high input imped-
ance VTVM for all AC signal voltage measurements; a
VTVM or 20, OOOQ/v YOM for DC volts measurements.
. If the trouble is an excessively distorted output, try tube
replacement, signal tracing, or procede directly to vol-
tage and resistance measurements.
When the defective stage is local ized, procede to a resist-
ance and voltage check of the stage, using the data in the
VOLTAGE and RESISTANCE chart. Disconnect theampli-
fier from the power line and discharge capacitors prior to
making any resistance check and prior to removing any or
all of theEL84output tubes. Do not turn the amplifier on
with any of the output tubes remove

CHECKING A TYPICAL TUBE STAGE
1. Check tube.
2. Check plate and cathode resistor.
3. Check coupl ing capacitors for leakage or short.
4. For output stage, check dc resistance of transformer
windings.
5. Check grid leak resistor for open.
6. Check cathode by-pass capacitors for short.
7. If no or low B+ voltage on tube, check decoupling
path for open or defective R60, R61, R62, R63 and fiI ter
capacitor C37, C38 or C39.
8. . If wiring and circuit components including the tube
check O. K. and B+ voltage is excessive)' check the de-
coupl ing path for short or defective R60, R61, R62and R63.
Suspected trouble in the equalization)' tone, focus, and
volume controls and networks should lead to specific re-
sistance and capacitance checks to localize the trouble.
In general, if the user suspects poor frequency response,
defective equal ization)' or defective operation of the tone
controls, the amplifier should be tested thoroughly with
audio generator, vtvm, and scope.
SPEAKER PHASING
IMPORTANT NOTE ON SPEAKER PHASING: The two
loudspeaker systems must be connected so that they operate.
in phase, meaning that corresponding cones or diaphragms
in the systems move in and out together when actuated by
the same or similar signals. A simple method of checking
this is to playa conventional monophonic (lateral) record-
ing having considerable bass program material, setting the
FUNCTION SELECTOR at MONAURAL. After listening
for a few minutes, reverse the connections of the speaker
leads at only one of the speaker systems - not both - and
listen again to the same program material. Normally, you
wi II noti ce that one of these connections seems to give
bass re-inforcement and the other bass cancellation. The
connection that gives bass re-inforcement is the in-phase
connection and should be used.
Another criterion for the in-phase connection is that of
blending, which can be best applied if the speaker systems
are identical or at least have similar middle and high
frequency range reproducers. With the in-phase con-
nection and both speakers operating at approximately the
same volume level, a monophonic source will appear to be
emanating from a point mid-way between and the two
speakers will blend. With the out-of-phase connection,
the two sources will appear to remain separate.
SERVICE
If trouble developes in your instrument which you can;.,t
remedy yourself, write to our service department listing
all possible indications that might be helpful. If desired
you may return the instrument to our factory where it wi
be placed in operating condition for $12. 50 plus the cost
of parts replaced due to their being damaged in the course
of construction. NOTE: Before returning .this unit, be
sure all parts are securely mounted. Attach a tag to the
instrument, giving your home address and the trouble with
the unit. Pack very carefully in a rugged container)' us-
ing sufficient packing material (cotton, shredded news-
paper, or excelsior), to make the unit completely immov-
able within the container. The original shipping carton
is satisfactory, providing the original inserts are used or
sufficient packing material inserted to keep the instru-
ment immovable. Ship by prepaid Railway Express, if
possible, to Electronic Instrument Co., Inc., 33-00 North-
ern Blvd., Long Island City I, New York. Return ship-
mentwill be made byexpress collect. Note that a carrier
cannot be held liable for damages in transit if packing
IN HIS OPINION)' is insufficient.

SYMPTOM
Amplifier causes power line fuse to
blow. Power line fuse blows again
with VII & V12 out of their sockets.
Amplifier causes power line fuse to
blow. Power line fuse does not blow
again with VII & V12 out of their
sockets.
Any or all tube filaments not lit.
Output tube bias too high (result-
ing in distorted output waveform).
DC voltage at Vl1, V12 cathodes
(pin 3) is incorrect as specified
below.
a) No voltage.
b) High voltage.
c) Low voltage.
Excessive hum on mag. phono tape
head or mic.
Excessive noise on mag. phono
tape head or mic.
Sustained oscillations.
Sustained microphonicson mag.
phono, tape head or mi c.
Hum on all inputs.
TROUBLE-SHOOTING CHART
CAUSE REMEDY
Line cord, J16, primary or high voltage Replace or repair.
secondary windings of T1 shorted internally
or externally (wiring).
VII, V12, C39)' V7, va, V9, VI0, or T2
T3 primary shorted internally or exter-
nally.
Open tube fil ament.
Open lead from 6. 3V winding of T1.
6 3 V winding of T1 open.
Open R56, R57.
Defective VII or V12.
C39 shorted internally or externally.
Connection from C39 to pin 3 of VII
& V12 broken.
Connection to center tap of h. v. second-
ary winding of T1 open.
Output tubes V7, VS, V9, VI0 over-
biased or not drawing current. May re-
sult from open R56 or R57.
Excessive current drain in amplifier.
Defective VII, V12.
VI or V2 defective.
FiI. leads dressed toa close to grid
lead.
Tube shield not making electrical con-
tact to base or base not making elec-
trical contact to chassis.
Shielding and grounding of wiring to
input jacks not exactly as instructed
and shown in drawings.
VI and V2 and contacts dirty.
Poor dress of output transformer T2 or
T3 leads.
VI or V2 defective.
V3 or V4 defective, not properly
shielded, or dirty sockets and contacts.
Dress of power transformer T1 leads.
Replace or repair.
Replace or repair.
Replace or repair.
Replace
Replace or repair.
Repair
'#" .
Repair
Replace, repair, or see trouble-
shooting typical tube stage.
See trouble-shooting typical tube
stage.
Replace
Replace
Dress fit. leads away from grid lead.
Check and correct.
Correct
Clean throughly with carbon
tetrachloride.
Dress all input leads and T3 leads
away from each other. Keep T3
leads away from input jacks.
Replace
Replace, correct, or clean.
Correct

VOLTAGE AND RESISTANCE CHART
TUBE PIN# OPERATING VOLTS OPERATING VOLTS SIGNAL VOLTS OHMS
AT NO SIGNAL AT 14W OUT (1 kc) at 30W OUT UN IT DISCONNECTED
(DC UNLESS NOTED) (DC UNLESS NOTED) FROM POWER)
CC83(12AX7 290KO
014 IMO
7KO
4&5 filament (OVDC; 6. 3VAC to pin 9) 500
290KO
0035 90KO
2KO
filament 500
ECC83/12AX7 290KO
IMO
7KO
4&5 filament (OVDC; 6. 3VAC to pin 9) 500
290KO
90KO
2KO
fi lament 500
ECC82/12AU7 1. 2 120KO
V3, V4 61OKO
. 1 3KO
4&5 filament (OVDC; 6. 3VAC to pin 9) 500
170KO
190KO
1. 8 1. 75 065 8KO
filament 500
ECC83/12AX7 195 190 100KO
V5, V6 470KO
100KO
4&5 filament (OVDC; 6. 3VAC to pin 9) 500
470KO
1. 15 250KO
1. 1 7KO
filament 500
EL84(6BQ5 340KO
,1, 340KO
12. 14.
. \.
1650
4&5 filament (OVDC; 6. 3V AC between pins 4 & 5) 500
330KO
335 325 180 165 1900
330KO
330 320 3500
EL84(6BQ5 340KO
340KO
12. 14. 03* 1650
4&5 filament (OVDC; 6. 3V AC between pins 4 & 5) 500
6 2 330KO
-,7 335 325 180 330KO
330 320 3500

EL84/6BQ5
V9, V10
EZ81/6CA4
VII, V12
4&5
4&5
* = 60 cycles
0 6.
12. 7 14. 7 . 03 *
filament (OVDC; 6. 3VAC between pins 4 & 5)
340KQ
340KQ
165Q
50 Q
335
330
325
320
165- 190 Q
330KQ
350Q
180
290 V AC * 29OV AC* 290* 45-55 Q
340 335 7.
filament (340VDC; 6. 3VAC between pins 4 & 5) 100KQ 100KQ
290V AC * 290* 45-55 Q
290V AC *
All resistance measurements, except those made from pin 3 of Vl1 and V12 (EZ81 rectifier), are
made with pin 3 of V11 and V12 grounded. All voltage and resistance measurements are measured
to chassis with the controls set as follows: INPUT SELECTOR to PHONO, FUNCTION SELECTOR
to STERO NORMAL)' LEVEL at 10, BASS, TREBLE & FOCUS controls at O. For voltage measurements
at 14W output, set the input selector to the PHONO position and feed a O. 0035volt (;3. 5mv) 1 kc
signal to the CH 1 & CH 2 Mag. Phono Input jacks; connect a resistive (preferably non-inductive)
load to the output of each amplifier, of equal resistance to the tap selected (::1:20%), and capable of
handling 15 watts. Voltage measurements are made with a VTVM. Operating line voltage atwhlch
voltage measurements are made is 117VAC, 60cps. NOTE: ALL VOLTAGE & RESISTANCE VALUES
NORMALLY BY::I:15%.

SECTION AUXA AUX B AM-FM FM-MUL TI MIC PHONO TAPE
INPUT
SELECTOR 11- 11-
SWITCH
S 1 2-6-
10-11- 10-11- 10- 12 10- 10- 11- 10- 11-
3- 7
4-11 1 -4- 2-4- 3-4-
3-6-
10- 10-12. 10- 10- 10-
1":12
10-
10- 10- 10- 9- 1 0- 10- 10-11
SECTION AMPL. 1 AMPL. 2 NORMAL REVERSE TUNER AUX. PHONO
FUNCTION
SELECTOR
SWITCH 4- 10 3-4-7
1) Entries are numbers of those switch contacts which are connected together by the rotors at the particular position.
NC means no connection.
2) On schematic diagram, all switch wafers shown in the maximum counter_clockwise position (AUXA and CH 1CHECK)as
seen from the front or shaft end.
TOP VIEW
~'-'t'~ ECC83/12AX7
~~L~~/6BQ5 ~~~84/6BQ5
~~~
84/6BQ5 ~~L~4/6BQ5
OPERATES FROM ""V
SO/6C CYCLE AC LINE
MODEL HF- POWER CONSUMPT'ON.
DUAL 14 WATT HIGH FIDELITY 140 WATTS
INTEGRATED AMPL"'ER
r'\ V- r'\
ECC83/12AX7V ECC82/12AU7V
r'\ r'\ V-
ECC83/12AX7V VECC83/12AX7
r'\V- 11 r'\V-
r'\V- VEZ81 \JEZ81
VECC82/12AU7
ELECTRONIC INST. 'CO.. INC.
noo NORTHERN BLVD
L , CITY 1 N Y
FRONT
AUX A
iUEIiJ.
MODEL HF- AUX B
DUAL 14 WATT HIGH FIDELITY
INTEGRATED AMPLIFIER OAM MULTIO
OFM
3 AMPS 117 VAC TAPE OUT SPEAKER CONNECTIONS
(Q) ITJJ 10 0 0 001 100000\ 000 000
CH- 2 CH. MIC PHONO TAPE MIC PHONO TAPE
CHANNEL 2 CHANNEL 1 CHANNEL 1 CHANNEL 2

REPLACEMENT PARTS LIST
Stock' Symbol Description Stock' Description
20050 Cl, cop. , paper
, .
25mfd, 200V ~1\T TB15, terminal strip, 2 past right
23014 C3, cop., elec., lOmfd, 6V 54000 TB17 terminal strip, lP left
23020 C5, cap., elec. , 25mfd, 6V 90034 Vl, tube, 12AX7
22517 C7, 33, cap., disc., . 025mfd, GMV (25K or 25,OOOmmf) 90033 tube, 12AU7
C35, 36, 45, 46 90039 V7, 8, 9, tube, EL84
22514 C9, cap., disc., 850mmf, "'10% 90038 Vll, tube, EZ81
22518 Cl1, cap., disc., . 0027mfd, "'10% (2. 7K or 2700mmf) 97800 XFl fusebolder
22550. C13, cap. disc., 6oommf, "'10% 97712 XII pilot assembly
22506 C15, cop. disc.
, .
02mfd, "'10% (20K or 20,000mmf) 97027 XV1, 2, 3, sacket, 9 pin min. w/shield
20039 CI7, 18, 21, cap.,molded,. lmfd, 400V, "'10% ...97025 XV5, 6, 7, 8, socket, 9 pin min.
22520 CI9, 20, 41, cap., disc., . 0012mfd, "'10% (1.2Kor 1200mmf) 10,
22529 C23, cap. disc., 150mmf, "'10% 40000 nut, hex, '6-
22543 C25, 26, 27, 28 cap., disc., 225mmf, "'10% 40001 nut, hex, '3/8-
23007 C29, cap., elec., 5Omfd, 25V 40007 nut, he", '4-40
22533 C31, 32, 43, 44 cap., disc., 47mmf, "'10% 40008 nut, he", '8-32
24005 C37 cap. , elec., 4O-40-20mfd/350- 350- 400V 40016 nut, for fuse holder
23016 C38, cap., elec., 30mfd, 4O0V 40026 nut, lin., '8-
20043 C40 cap., molded, .03mfd, 600V 40027 nut, tin., angle bracket
22519 C47, 48 cap., disc., . 0Imfd, "'10% (10K or 10,000mmf) 41000 screw, '6- 32 x 1/4
91005 fuse, 30mp 41003 screw, '8- 32 x 3/8
92000 pilot light, '47 41016 screw, '4-40 x 1/4
50020 JI- jack, quad, 41026 screw, '4-40 x 1/4 brass
50018 J5- jack, triple 41027 screw, '4 wood
10. 41028 screw, '8- 32 x 1
11-12- 41045 screw, '6 P. K. brown
50011 J14- jack, dual 41046 screw, '8- 32 brown
50016 J16 outlet, convenience 41047 screw, '8 P. K.
"'" 29751 PCl, printed circuit 42000 washer, '3/8 lock
10407 Rl, res., IMQ, 1/~, "'10% (brown, black,green, silver) 42002 washer, '6 lock
..,..
10400 R:r,4, 40, 41, res., 10KQ 1/~, "'10% (brown, black, orange, silver) 42007 ~sher, '4 lock
53, 54, 42008 washer, '8 lock
11526 RS, 6, 11 res., 200KQ, 1/~, '" 5% (red, black, yellow, gold) 42029 washer, rubber, forfuseholder
10423 res., 2. 2KQ, 1/'NI, "'lOOk.
(red, red, red silver) 42032 washer, fiAt, '8
10430 R13 res., 4. 7KQ, 1/~, :10% (yellow, vi~let red, silver) 43000 lug, '6 ground
11504 R15, res., 90KQ, 1/'NI 5% (white, black, orange, gold) 43001 lug, '3/8 pot ground
11527 RI7 18, 44, 45, res., 100KQ 1/'NI, '" 5% (brown, black,yellow,gold) 43004 lug, 18 ground
46, 46000 grommet, 3/8
10422 R19 20, 60 res., 68KQ, 1/'NI, :10% (blue, grey, orange, silver) 46006 feet, rubber
11518 R2I, res. , 2.2MQ, l('NI, : 5% (red, red, green, gold) 50012 insulator for 50011
_18045 R22, 23 pot. , 750KQ linear, dual 50019 insulator for 50018
---., 8046 R24, 25 pot., 250KQ, audio, dual 50021 insulator for 50020
10435 R26, res., 150KQ,
1/~, :10% (brown,green,yellow, silver) 51006 pbono plug
10414 R28, 29 res., I. 8KQ, 1/~, :10% (brown, grey, red, silver) 53016 knob, outer concentric
18048 R30, pot., IMQ, linear
, concentric 53017 knob, inner concentric
18047 R32, 33, 54 pot. , 500KQ, linear, concentric
w/SPST switch 53018 knob, duell concentric
10410 R34, 35, 68, 69 res", 100KQ, l(ZW, %10% (brown, black, yellow, silver) 57000 line cord
10420 R36, res., 3. 3KQ, l(~, %10% (orange, orange, red, silver) 58004 wire, hook...p, thin wall length
10431 R38, res., 470KQ, 1/~, :10% (yellaw,violet,yellow, silver) 58300 spoghetti length
11543 R42, 43 res. , 1.8KQ, l(~, : 5% (brown, grey, red, gald) 58302 spaghetti, heavy length
10412 R48, 49, 50, 51" res. , 330KQ, 1/~, :10% (arange, arOnge, yeilow, sHver) 58408 cable, 1 conductor length
58410 cable, 4 conductor length
14600 RS6, 57 res., 1650, !)N, % 5% 58412 cable, 3 conductor length
11538 RS8, 59 res., 22KQ, 1/~, % 5% (red, red, orange, gold) 58501 wire, bare length
10851' R61 res., 22KQ, lW, %10"k. (red, red orange, silver) 80057 panel
10952 R62 res., 4. 7KQ,~, :10% (yellow,violet, red, silver) 81109 bottom plale
14302 R63 res., 3500, lOW, :10% 81110 brocket, left
19009 R64 pot" 100Q 81111 bracket, right
10421 R70, 71 res., 6. 8KQ, 1/~, :10% (blue, grey, red, silver) 81116 bezel
60057 switch, Input Selector 81124 chassis
60065 switch, Function Selector 81134 shield w/spade bolls
62000 switch, slide, DPDT 81144 perfomled screen
62002 switch, slide, SPOT 81145 bracket~ Input
30021 transformer, power 81146 bracket far DPDT switch
32013 T2, 3 transformer, output 81154 shield bottom
54516 TB1, terminal board, 5 screw 81903 clamp, wire
54002 TB3, terminal strip, lP right w/ground 89207 label, rear apron
54001 T84 terminal strip, IP right 89208 label, tube layout
54014 TB5 terminal strip, 3P 2 left 89219 label, service
54003 TB6,7, 13, terminal strip, 2 past 97300 tube shield
54006 TB9, 11, 18 terminal strip, 3P 2 right 97710 Jewel, red
54013 TBIO, 19 terminal strip, lP left w/ground 66067 manual af instructions (wired)
54008 TBI2, 14 terminal strip, 4 past 66316 manual of instructions (kit)

Jl0
J13
J12
Jl1
';'
... Cl
",,-,
-c4
....c6
.... C7
~C8
=CIO
- ClI
..:.CJ2
-c13
........C14
-CJ5 -'J6
,...CJ7 -CJ8
--C19
--C20
.....C21
-C22
-C23
~C24
""C25
""1:26
C13
Description
cap.,paper, . 25mfd 200V "'-C27 cap.,paper, . 25mfd 200V ~C28 cap., elec., 10mfd 6V - C29 cop., elec., IOmfd,6V ,.-C30
cap., elec., 25mfd 6V "'C31 cap., elec., 25mfd 6V ;;,-C32 cap., disc., . 025mfd GMV ,C33 cap., disc., . O25mfd, GMV -C34
cap., disc., 850mmf, %10% ""C35 cap., disc., 850mmf, %10% . C36 cap.,disc. , . 0027mfd, %10% ;"C37 cap., disc., . 0027mfd %1O% ...C38 cap., disc., 600mmf, %10% ......c39
cap., disc., 600mmf %10% .....,('C..uJ
cap., disc.
, .
02mfd %10% -C41
cap., disc., . 02mfd, %10% "..,c42 cap., molded, . Imfd,..uJOV, %IO%-C43
cap. molded, . Imfd,..uJOV, %IQ%- C44 cap., disc., . 00J2mfd, %IO"k .?C45 cap., disc.
, .
OOJ2mfd %10% "C46
cap., molded, . I mfd, ..uJOV, %1O%-C47 cap., molded, . 1 mfd, ..uJOV, %1O%-"'C48 cop., disc. , 150mmf %10% '-Jl cap., disc., 150mmf,%10% _ cap., disc. , 225mmf %10% -:13 cap.,disc., 225mmf %10% -~'4
';' ';'
Description
cap.,disc., 225mmf %JO% cap., disc., 225mmf,%IO%
cap.,elec., 50mfd 25V cap.,elec., 50mfd,25V cap.,disc., 47mmf,%10% cap., disc., 47mmf,%10%
cap., disc., . 025mfd, GMV cap., disc., . 025mfd, GMV cap., disc., . 025mfd, GMV
cap., disc., . 025mfd, GMV cap.,elec., 40-40-20mfc!/350-
350-400V
cap., elec. , 30mfd,..uJOV cap., elec., 3Qmfd,4OQV
cap., molded, .03mfd OOOY
cap., disc. , . 00 12 mfd, %10% cap., disc.
, .
0012mfd %1O%
cap., disc. , 47mmf, %JO% cap.,disc. , 47mmf, %10%
cap.,disc., . O25mfd, GMV cap.,disc., . 025mfd, GMV cap.,disc., . OJ mfd,%l0% cap. , disc.. . 0Imfd %10%
aux A - channel I aux B - channel I
MODEL Hf-
DescriJ'tion
~~~
d'l
"JI0 ,-:Ill
"JI2
JI3
..J14
:)15
-116
RJO RlI R12
RI3
aux A - channel 2 DUX B - channel 2
multiplex mic - channel I
phono - channel I tope - channel I mic - channel. phono - channel 2
tope - channel 2 tope output - channel 2 tope output - channel I ac pawer
res., IMQ. I/2N, %10%
res., JMQ, I/2N, %JO%
res., 1OKD.
I/2N, %10%
res., 10KD.
I/2N, %10%
res., 200KD. I/2N,
% 5%
res., 200KD.J(2N, % 5% res., 2Kn, J(2N, %10%
res., 2.2KD.I/2N, %10% res., IMQ, I/2N, %10% res., JMQ, I/2N; %10% res., 200KQ,
I/2N, % 5%
res., 200KD. I/2N,
% 5%
res. 7KD.I/2N, %JO%
R71 4"5
';'
JI4
R59 C31
';'
JI5
R58
C18
C32
R32
R42
';'
'IV
R60 R61 R62 R63
RJ4 RJ5 R16
R17
RJ8
R19
R20 R2l
;:.oR22
R23 R24
--rt25
R26 R27 R28 R29
--R30
R31
--
R32 R33
R34 R35 R36 R37
R38
Descri tion Description 5ym Description
res., 4.7KD. I/2N,
%10% R39 res" 470KD. I/2W, %10% R64 pat., 1O0Q
res., 9OKD. I/2N, % 5% R..uJ res., lOKn, J(2W, %10% R65 res., 330KQ, I/2W, %10% res., 9OKD. J(2W, % 5% R4l res., 10KQ, I/2W, %IO"k R66 res., 330KQ, 1/2W, %10% res., lOOKQ,I/2N, % 5% R42 res., 1, 8Kn, I/2W, % 5% R67 res., 2. 2MQ, I/2W, % 5%
res., 100KQ,I/2W, % 5% R43 res., 1. 8KD.I/2W, %5% R68 res., IOOKQ, I/2W, :10% ..1f37C ..1f378 .1f37A ..1f38 res., 68KQ, I(2W, :10% R44 res., 100KQ, I/2W, : 5% R69 res., 1O0KQ, I/2N, :10%
res., 68KQ,
J(2N, :10% R45 res., 100KQ,
I/2N, R70 res., 6, 8KQ, I/2W, :10%
res., 2MQ,J(2W, :5% R46 res., 100KD. I/2W,: 5% R71 res. , 6.8KQ, 1/2N, :10%
pot. , 750KQ linear, dual R47 res., lOOKD. I/2W,
% 5% -51 switch, input selector
pot., 750KQ linear, dual R48 res., 330KQ, I/2W, :10% switch, function selector
pat., 250KQ, audio, dual R49 res., 330KD. I/2W,:10% switch, slide, DPDT
pat., 250KQ, audio, dual R50 res., 33OKQ, 1(2W,:10% switch, 5P5T, port of R32, res., 150KQ,I/2N, %10% R51 res. , 330KD.J(2W, "'10% -55 switch, slide, 5PDT res., 150KQ,I/2N, "'10% R52 res., 1OKD. J(2W,"'10% --VI tube, 12AX7
res., 8KD.I/2N, "'10% R53 res., lOKQ, I/2N, %10"k tube, 12AX7 res., I. 8KQ,
I/2N, %10% R54 res., 10KD. I/2W,%10% ... V3 tube, 12AU7
pot. , IMQ, linear, concentric R55 res. , lOKn, I/2W, :10% tube, 12AU7 pat., lMQ, linear
, concentric -R56 res. , 165Q, !NI, .V5 tube, 12AX7
pat. 500KD. linear, concentric - R57 res., 165Q, !NI, 5%. "-...V6 tube, I
2AX7
pot., 500KQ, linear
, concentric R58 res. , 22KQ, I/'M, % 5% ""V7 tube, ELM
res., lOOKD.
I/2N "'10% R59 res. , 22Kn, I('M, % 5% -V8 tube, ELM
res. , lOOKD. I/2N, "'10% R60 res., 68KQ, I/2W, :10% -V9 tube, ELM res., 3. 3Kn, I/2W, %JO% R61 res., 22KQ, IW, :10% -VIO tube, ELM res., 3. 3KQ I/2N, "'lO"k R62 res., 7KD. I/'M, :10% ....VII tube, EZ81
res_, 470KQ, I/'M, "'IO% =-R63 res., 350Q, lOW, %10% .......VI2 tube, EZ8J
DUAL 14 WATT HI-
----
VllVI2
STEREO AMP. PREAMP
(g)
1958