Bogen MU1250 Operating Manual

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MODEL MU'I250

50 WATT TRANSISTORIZED
MOBILE PUBLIC ADDRESS AMPLIFIER

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INSTALLATION AND OPERATING MANUAL

READ THOROUGHLY BEFORE OPERATING EQUIPMENT

IMPORTANT: BEFORE INSTALLATION READ CAREFULLY CAUTION NOTES ON PAGE 3

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DESCRIPTION

The Bogen Model MU1250 is a 50-watt transistor-
ized mobile public address amplifier. The microphone
input, phase inverter, and driver amplifier stages are
plug-in modules, which facilitates maintenance of
the unit.

Five separate inputs are provided on the am-
plifier. Two are for microphones, either high or low
impedance. No plug-in transformer is required with
low-impedance microphones. One of these inputs will
also accept signals from a magnetic phonoortapehead.

The two auxiliary inputs will accommodate a
crystal or ceramic phonograph, a radio, a tape recorder
or other high-level, high-impedance input. A master
volume control regulates the over-all gain, and separate

TECHNICAL SPECIFICATIONS

POWER OUTPUT: 70 watts peak; 50 watts at less
than 10% distortion (continuous).

FREQUENCY RESPONSE: 30 to 15,000 Hz (cps),
12 db.

HUM AND NOISE (below voted output): MIC input,
65 db; AUX input, 70 db.

GAIN: MIC input. 125 db, AUX input, 95 db;
MAG input, 110 db.

SENSITIVITY: MIC input, 2 miIlivolts (low im-
pedance), 3 millivolts (high impedance);
AUXinput, 0.5 volts; MAG input, 18 millivolts.

INPUTS: 1 MIC (high or low impedance); 1 MIC
(high or low impedance) or Mag Phono or
Tape Head; 2 AUX (high impedance, high
level).

OUTPUTS: 4, 8 and 16 ohm speakers, 25 volt
balanced line, 70 volt line. (Two quick-

bass and treble controls are incorporated for adjusting
tonal balance.

The model MU1250 may be used with either a
117 volt, 50/60 cycle AC source or with a 12-15 volt
battery. Two power cables are provided, one for AC
power, the other for DC. The DC power cable is pro-
vided with alligator clips for connection to a 12-15
volt battery.

Outputs are provided for use with 4 ohm, 8 ohm
and 16 ohm impedance speakers as well as for opera-
tion with 25 volt and 70 volt line speaker systems.
Two quick-disconnect plugs are furnished for making
rapid connections to the speaker system.

disconnect sockets and connectors provided
in addition to screw-type terminals.)

TONE CONTROL ACTION: Treble (at 10 kHz),
-11 db; Bass (at 50 Hz), +14 to -9 db.

CONTROLS: MIC 1 Volume, Input 2 Volume, MIC
1 Impedance Selector switch. Input ZSelector
switch, AUX 1 and 2 Volume (tader type),
Master Volume, Bass, Treble, Power switch.

TRANSISTORS AND DIODES: Two 2N3053, four
MP56521, three MP56514, two 2N1558; three
silicon diodes; two zener diodes.

POWER CONSUMPTION: At 117 VAC, no signal,
16 watts, max signal, 116 watts. At 14 VDC,
no signal, 0.3 amp; max signal, 6.7 amp.

OPERATING TEMPERATURES: -20°C to +65°C
(-4°F to +149° F).

DIMENSIONS: 153/4" wide x 63/4" high x 10 deep.

SHIPPING WEIGHT: 23 lbs.

NOTE: The units of frequency measurement, cps (cycles per second), KC (kilocycles), and MC (megacycles)
are being replaced by the designations Hz (Hertz), KHz (Kilohertz), and ME: (Megahertz). respectively. These
new designations. now in standard use throughout the rest of the world, have recently been adopted by the

Institute of Electrical and Electronic Engineers (IEEE).