Free Audio Service Manuals - Free download western electric 63 a schematic

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Wamm Electric Company
No.63-A AMPLIFIER

AMPLIFIER
No. 63A

Iyzsmat/om for Use

The No. 63A Ampliﬁer illustrated above and shown schematically in Figure 1
is a single-stage AC operated ampliﬁer designed to amplify the output of a carbon
transmitter, condenser transmitter ampliﬁer or of a mixing panel into which several
transmitters are operated, to a level suitable for the input of the main ampliﬁer,
such as the Western Electric No. 59A or No. 59B Ampliﬁer, in public address systems.

The gain of the ampliﬁer is approximately 30 db. One No. 262A Vacuum Tube
is employed in its operation. The ampliﬁer is designed to obtain plate energy from
a high voltage rectiﬁer such as may be included in the main ampliﬁer, or a battery
which will supply 4.5 milliamperes at 360 volts.

The ampliﬁer is designed to operate from an impedance of 200 ohms and has
an output impedance of 200 ohms, so that it may be connected directly to the input
of the main ampliﬁer of the system. The primary winding of the input transformer
is provided with a mid-tap for operation from a double button carbon transmitter.
A milliammeter is connected in the plate circuit of the ampliﬁer to indicate the
plate current of the No. 262A Vacuum Tube.

751.

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WWI-u ﬂecnic Company
No.63-A AMPLIFIER

the terminals similarly marked on the main ampliﬁer terminal strip. In general,
the -360 v. and GND terminals of the No. 63A Ampliﬁer should be strapped
together. If the ampliﬁer is excessively noisy, it may be found that less noise is
obtained by removing the connection between the -360 V. and GND terminals.

A diagram showing the connections between a No. 59 Type Ampliﬁer and a
No. 63A Ampliﬁer is shown in Figure 3.

No.59 TYPE AMPLIFIER

AC LINE OUTPUT
AC PLATE FIL com MON
SUPPLY 9': Clo
_.. 500
AC POWER our 7': «:5
F' F c GND 3
n [I] Sr: 56
AUX AMF
+360 +350 ~3ao 3: 2
I] II
GND
::< _l_
INPUT 1
[l G
| MID Z _
SHIELDED
no.5» AMPLIFIER TWISTED
SHIELDED
n / PM.
TERMINAL INPUT INP
wm-I NICKEL I; 2:: H / _U_T_
FINISHED
SCREW i MEID
/ GND
I] I II =
AC LINE +300-
0ND 3I-_L. 4.:
OUTPUT

Fig. 3-Diagram of Connections Between No. 59 Type and No. 63A Ampliﬁers

When the No. 63A Ampliﬁer is used in a system having one or more No. 59
Type and No. 57A Ampliﬁers, it may be desirable to control the AC power to a
number of ampliﬁers by means of the power switch on one No. 59 Type Ampliﬁer,
or by a remote switch or relay circuit which provides the proper sequence. Facilities
for controlling power to a number of ampliﬁers are provided on the No. 59A and
No. 59B Ampliﬁers by means of six terminals marked C", P", F" and COM,
"FIL" and PL. To use this arrangement, the AC power source should be connected
to the AC LINE terminals marked COM and FIL of the No. 59A or No. 59B
Ampliﬁer which is to act as the control point. The terminals marked Ac LINE" in
the No. 63A Ampliﬁer should be connected to the C" and F terminals of the
No. 59 Type Ampliﬁer which is to act as the control point, with the terminal having
a nickel ﬁnished screw in the No. 63A Ampliﬁer connected to the terminal marked
C in the No. 59 Type Ampliﬁer.

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Western electric 63 a schematic

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