6
Output Connections
Speakers, General
The amplifier may be used with most conventional speaker systems. Connect one speaker lead to the screw ter-
minal that corresponds to the total impedance or proper voltage of the speakers used in the system and the other
lead to the COM terminal. For balanced output lines, remove the link between the COM and GND output termi-
nals. Class 2 wiring may be used.
Operation
POWER
The front panel ON/OFF switch applies power to the amplifier.
MIC
1
, MIC2
For two microphone inputs, the MIC2/AUX selector switch should be in the MIC2 mode. The MIC controls are
used to adjust the volume of the microphone inputs. Rotate the controls clockwise to increase volume and coun-
terclockwise to decrease it. Turn the controls to the minimum counter-clockwise position if the inputs are not
used.
AUX
For one auxiliary input, the MIC2/AUX selector switch should be in the AUX position. The AUX control is used
to adjust the volume of the auxiliary input. Rotate the control clockwise to increase volume and counterclockwise
to decrease it. Turn the control to the minimum counter-clockwise position if the input is not used.
TEL
The TEL volume control on the rear panel adjusts the telephone paging level. It does not affect the microphone
level. Rotate the control counter-clockwise to decrease the level. Rotate the control clockwise to increase the
level. Turn the control to the minimum counter-clockwise position if the input is not used.
VOX SENS
The VOX SENSitivity control should be set so that only the desired TEL signal is above the threshold level, while
noise and unwanted signal is below it. When an input signal (such as a voice) is detected, the AUX channel will be
muted. To adjust the sensitivity of the circuit:
1
. Rotate the control fully clockwise. While making a page announcement and talking at a low level, the sound
should not be choppy nor missing parts of words. If it is choppy, or if intelligibility is poor, rotate the con-
trol counter-clockwise to the point where the sound is clear and crisp (but not to the maximum counter-
clockwise position).
2. If the background music shuts down when no page is in progress, rotate the control clockwise until the
music is restored.
Microphone Precedence
Muting the AUX channel can be accomplished with a customer-supplied normally-opened SPST switch, which must
be connected to the MUTE terminals. When the contacts are closed, the microphone will have precedence over
the AUX input.
TREBLE
Use the TREBLE control to adjust the tonal balance of the amplifier output. Rotated fully clockwise there is no
effect. Rotate counter-clockwise to attenuate the TREBLE of the audio.
Overload Protection
The amplifier output is protected against overload and shorted speaker lines by an electronic shut down circuit and
a thermostat enclosed in the power transformer. If the protection operates, the amplifier will have no output. Set
the Power switch to off and wait a reasonable amount of time for the protection to reset. If the protection trips
again, have the problem investigated by a qualified technician.
