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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
the
speaker nameplate.
Con-
nect
one
speaker
lead
to
the
"
G
M
terminal
on
the rear
apron
and
the other
speaker lead
to
the
nearby
terminal
corre-
sponding
to
the rated
speaker
Impedance
(4,
8,or16ohms).
Plastic-covered
lamp
cord
maybe
used
for
distances
up
to
50
ft.
with
little
power
loss.
For shorter distances,
TV
antenna
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
only)
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 the 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-over 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
with a
shielded plug.
The
loading
resistance
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
for
receiv-
ing the
output
signal directly
from
the
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
loading
resistance
presented
to
the
tape
head
Is
100,000 ohms.
d)
HIGH
LEVEL INPUTS: Two
high
level
Input Jacks
des-
ignated
as
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
"phono-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
(with
which up
to
50ft.
of
cable
can be
used), use theshortestposslble
connection
and
low capacity shielded cable
(cable
having
as
low
as
25mmfd
capacitance
per foot
Is
available).
If
the tuner
employed
has a
volume
control
to
adjust the
output,
set
this
control
to
give about
the
same sound
level
for
any
given
setting of the
amplifier
VOLUME
control as
obtained from an average
orchestral
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
vice
versa.
e)
TAPE
OUTPUT:
A
shielded
cable
(up
to
30
ft.
may
be
used) with a shielded
"phono-type"
plug should
be used
to
connect
from
the
TAPE
OUTPUT
Jack
to
the Input of the
tape 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
the
RIAA
characteristic
and
all
the Inputs are
af-
fected
by
the level
and
tone
controls.
f)
POWER CONNECTIONS:
The
117VAC,
250
W
re-
ceptacle
is
"live" or
"dead" depending on whether
the
amplifier
power
switch
is
turned
on
or
off.
By
plugging
Into
It
the line cords 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
turntables
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
make
the
follow-
ing control settings
which
hold throughout the process of
hum
adjustment:
SELECTOR
at
PHONO,
LEVEL
to
10,
TREBLE
control at
"5,
BASS
control
at 0.
Next, procede
as follows:
With
your
ear held close
to
the
speaker,
insert
the amplifier
power
plug
into the
wall outlet
and
listen to
the
hum
level.
Now
pullout
the
plug
and
reinsert
it
with
the prongs reversed
and
listen
again.
Choose
the
prong
position
which
gives the
least
hum
,
Now
connect
the
tuner
Input
connector
to
the amplifier input jack,
and
with tuner
set
between
stations
and
the tuner
volume
control
set
at
minimum,
do
the
same
with
the
power
plug
of
the tuner,
using the
117VAC
convenience
outlet
on
the
amplifier
if
desired. Finally
connect
the
phono
input
connector
to
the
amplifier
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.
4
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