Dimensions
Carri.Jing Cases
Amplifier Control Unit
AC Power Unit
14" x 16%." x 7%."
9" x 15" x 5"
6Vs" x 13" x 4"
Weight
Carrying Cases (each)
Amplifier Control Unit
12 lbs.
15 lbs.
Total Battery Weight
(Depending on batteries used)
AC Power Unit
16 to 18 lbs.
81/:? lbs.
Finish
Carrying Cases
Amplifier Control Unit
Black Fabrikoid
Amplifier Cabinet is gray crinkle finish and the panel
non-glare "Alumilite".
GENERAL
The Western Electric 22E Speech Input
Equipment is compact, light in weight, port
able, and designed to provide complete pick
up facilities for remote broadcast programs.
The equipment consists of a combination am
plifier and control unit with a carrying: case,
and either a power unit for a-c operation, or
battery accessories, or both, as specified, with
a carrying case and connecting cords. The
space available in the power supply carrying
case is adequate
to
permit carrying both the
battery and a-c power supplies simultaneous
ly, if desired. When both the a-c and the
battery power supplies are utilized, the bat
tery supply cable plugs into a jack on the
a-c power supply chassis, and a plug and
cable connect from the a-c supply to the am
plifier unit. Two switches on the a-c power
supply enable the operator to operate the
amplifier from either the a-c supply or the
battery supply, or to operate the filaments
from a-c and the plates from battery, or vice
versa, as may be required.
Receptacles and parallel mixing potentiom
eters are provided for four microphones. A
master gain control is incorporated in the
3-stage amplifier. Pads for either 150 or 600
ohm output are selectable by means of a
switch. Provisions are made for connections
to two telephone lines, one normally used for
2
program transmission and the other for an
order wire circuit. Two output line keys per
mit the operator to switch the lines at any
time in case of emergency, thus making both
lines available for broadcasting. A standard
volume indicator with attenuators for output
levels from +4 to +14 vu is used for moni
toring the level of the outgoing program, and
is also used as a voltmeter to indicate the
condition of the batteries.
Binding post terminals and a multipled
jack provide connections to a telephone set
for communication with master control, and
two headset monitoring jacks permit aural
monitoring of the program by the operator
and a second person.
The amplifier has a net gain of approxi
mately 90 db, and the frequency response is
essentially uniform over the range from 35
to
10,000 cycles (see Figure 1). For fundamen
tal frequencies from 100 to 7,500 cycles per
second the harmonic distortion is less than
17r at output levels up to +18 dbm. (See Fig
ure 2). The unweighted noise level is 65 db
for battery operation or 62 db for a-c opera
tion at +18 dbm with 70 db net gain.
The rear cover of the unit can be quickly
removed for access to the vacuum tubes and
other amplifier components without discon
necting any of the cords.
