Speco PBM-15 Instruction Manual page 4

FRONT PANEL
1) MIC-1 Volume control. Adjusts audio level of MIC-1.
2) MIC-2/AUX Volume control. Adjusts audio level of MIC-2/AUX.
3) Bass Control. Low frequency tone control.
4) Treble Control. High frequency tone control.
5) Power on/off switch with indicator. Illuminates when power is on.
REAR PANEL
1) AC accessory outlet (Unswitched). Unswitched AC Auxiliary outlet for a 120VAC. 50/60Hz
power source.
2) AC fuse holder.
3) MOH output level control. Controls volume of MOH output. (Music on hold)
4) MIC-2/AUX input selector switch. Allows for selection of either low impedance MIC-2 input or
high impedance AUX input.
5) AUX input RCA jacks. Provides connection for a booster amplifier. The input impedance of the
equipment should be more than 600 Ohm.
6) TEL/PAGING output level control. Controls audio level of telephone output.
7) TEL/PAGING balanced input terminals. Accepts a balanced telephone paging signal.
8) MIC-1 balanced input terminals. Accepts a balanced low impedance microphone signal.
9) MIC-2 balanced input terminals. Accepts a balanced low impedance microphone signal.
10) Manual muting terminals. Provides contact closure muting of the MIC-2/AUX input during
paging.
11) MOH output terminals. Provides two MOH outputs 600 Ohm, 1 Volt and 8 Ohm, 1 Watt.
12) Speaker outputs. Speaker lines must be connected to "COM" and one (and only one) of
the remaining screw terminals.
13) Ground. Cabinet enclosure unit ground.
14) AC power cord. AC power cord with three pin plug for a 120VAC 50/60 Hz, power source.
Do not defeat the ground pin.
Note: MIC-1/TEL input include internally adjustable (factory set) VOX muting of the MIC-2 and AUX
input during paging.
Screw terminal designations : G-GND, HOT-Signal positive, COM-Signal negative/common.
Overcoming Ground Loop Problems
If the amplifier is mounted in a rack unit (Use rack mount part # PBM-RK1), or is used with
equipment having its own ground, it is necessary to ensure that ground loops and the associated
problems of hum on the output signal are not introduced by the ground wiring. (see warning)
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