AUDAC COM12 Mk2 User Manual - page 16
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2) Connecting the audio sources
The next step is making the signal input connections. Depending of the type, connection
and output level of the available audio sources they should be plugged into the matching
channel / connection.
Before connecting, turn all the channel input and master colume controls on the front
panel of the amplifier fully counterclockwise (to their minimum setting) and put the gain
control trimmers on the rear panel in a central position. Then connect all the available
sources to their corresponing channels and switch on the power of the amplifier and all
the connected audio sources. The power and protection LED will light-up now. After
approximately five seconds, the protection LED will stop illuminating (a click will be heard
when this occurs)
Apply a signal to the inputs as it will be used in normal operation circumstances and turn
the channel input level control up about 50%. Slowly raise the master volume control till a
certain level until the desired sound level is achieved. Depending of the output level of the
connected music sources, the input gain might need adjustment. Adjust these trimmers
on the rear panel until the desired level is achieved.
For the best signal to noise ratio, the COM series amplifier should run in normal
circumstances with the master level control near maximum position and the peak
indicator (+3 dB) of the VU meter on front should light occasionally (but not frequently)
during peak levels. If the signal is too loud or distorted, use the input level controls to
attenuate as necessary to achiee the desired speaker level.
3) Priorities
Channel 1 and 2 contain a priority switch, whereby the priorities for the corresponding
channels can be enabled or disabled. When the priority is switched ‘ON’, other input
channels will be muted in case a signal is present on the corresponding input.
In addition to the priority muting on channels 1 and 2, some priorities are available which
are always active. They are set in four different levels in the following order:
1) Chime & tele-paging (highest priority)
2) Remote mic
3) Channels 1 and 2 (priority enabling by switch)
4) Channels 3 to 6 (no priority)
If a tele-paging call occurs or the chime switch is pressed, all other inputs are muted. If a
signal is present on the remote mic input, channels 1 to 6 will be muted. Signals with the
same priority level will stay on simultaneously.
4) Phantom power
Channel 1 to 4 contain the possibility for supplying 15 Volts phantom power for powering
condenser microphones. Enabling of the phantom power can be done by the switches
located above channel 1 & 2 connections. The first switch is only effective on channel 1,
while the second switch enables phantom power for channels 2 to 4.