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electrical Installation
_
GENERAL
a) SPEAKER CONNECTIONS: To connect your speaker
to the amplifier properly, you must know Its rated Imped-
ance
.
This may be read off tne speaker nameplate. Con-
nect one speaker lead to the" G"termlnal on the rear apron
and tne other speaker lead to tne nearby terminal corre-
sponding to the rated speaker Impedance (4, 8, or 160hms).
Plastic-covered lamp cord may
be
used for distonces up to
50 ft. wltn little power loss. For shorter distances, TV
ontenno
lead can be used, particularly If It Is desired to
run the speaker lead under a rug.
If It Is desired to use two similar or Identical full-range
speakers of the same rated Impedance (either 8 or 16 ohms
on
ly)
for better sound distribution, connect one speaker
lead of each pair to "G" and the two remaining leads to
the terminal with a number equal to half of one of the
speaker's rated impedance. (It may be necessary to "phase"
the two speakers by reversing both of the leads from one
of tne speakers.) This may not be done if each of the
speakers Is designed for reproduction of a different part
of the audio spectrum (woofer-tweeter combinations) In
which case a cross-ever network Is required which con-
nects to the amplifier with only one pair of leads.
b) MAG. PHONO INPUT: This Input is intended for use
with phonographs having magnetic cartridges. The shield-
ed lead from your phonograph should be provided wltn a
shielded plug. The loading reslstonce presented to the
cartridge at the Input Is 47,000 ohms, which Is the most
generally suitable loading resistance for magnetic cart·
ridges.
c) TAPE HEAD INPUT: This Input Is Intended
fer
receiv-
Ing tne output signal directly from tne playback head of a
tape deck. NARTB tape head equalization for 7 1/2 and
15 I.p.s. tape speeds Is applied to signals fed In at this
Input. The load
ing
resistance presented to the tape head
Is 100
,000 ohms.
d) HIGH lEVEL INPUTS: Two high level Input Jacks des-
Ignatedas Tuner and Auxiliary are provided for connection
of tuners,
tv
receivers, equalized and pre-ampllfled tape
recorder playback, and ordinary or RIAA equalizing crystal
or
ceramic phono cartridges without adaptor. A shielded
cable with a shielded "phone-type" plug should be used
to connect each of these sources to the corresponding am-
plifier input Jack. Unless the source has a low-Impedance
output such as a cathode follower{wlth which up to 50 ft.
of cable can be used), use tneshortestpasslble connectton
4
and
low capacity snlelded cable (cable having as low
01
25mmfd capacitance per foot Is
available) .
If ftle tuner employed has a valume control to adlust ftle
output, set this control to give about tne same sound level
for
any given setting of the amplifier VOlUM Econtrol
01
obtained from an average
orchestra l
recording played on
your phonograph. If you do this, there will not be any
extreme change in sound level when switching from phono-
graph to tuner or vi ce versa.
e) TAPE OUTPUT: A shielded cable (up to 30
ft.
may
be
used) with a
shie lded "phone-type"
p
lug
should be used
to
connect from the TAPE OUTPUT lack to the Input of
the
~pe
recorder. Any input chosen by the SELECTOR Is fed
out to the tape recorder through this jack. Phono inputs
fed In at MAG. PHONO are of course equalized accord-
Ing to tne RIAA characteristic and a
ll
the inputs are af-
fected by the level and tone controls.
f) POWER CONNECTIONS: The 117VAC, 250W re-
ceptacle is "live" or "dead" depending on whether the
amplifier power switch is turned on or off
.
By plugging
Into It the line co
rds
of associated equipment (tuner, tape
recorder, etc.) it is possible to turn these components on
or off with the amplifier.
Use a cube tap if It Is desired
to connect more than one device. Record changers and
tumtables should be plugged into a wall outlet as a pro-
tection to the mechanisms of
these
units.
HUM ADJUSTMENT
a) After checking the amplifier for proper operation, re-
move all input cables to the amplifier and makethe follow-
Ing control settings which
hold
throughout the process of
hum adjustment: SELECTOR at PHONO, LEVEL to 10
,
TREBLE centrci at -5, BASS control at O. Next, procede
01
follows: With your ear held close to the speaker, insert
the amplifier power plug into the wall outlet and listen to
tne hum level. Now pull out the
plug
and reinsert it with
tne prongs reversed and Iisten again
.
Choose the prong
position which gives the least
hum.
Now connect the tuner
input connector to the amplifier input jack, andwlth tuner
set between stations and the tuner volume control set at
minimum, do the same with the power plug of the tuner,
using
tne 117VAC convenience outlet on the amplifier if
desired
.
Finally connect the phono input
connector
to the
amplifler MAG. PHONO or AUX. Input (as required) and
find the lowest hum position for the power plug of the
phonograph In a wall outlet. Do this with the phonograph
off and the pickup arm at rest position.
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Table of Contents
Troubleshooting
