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The rear panel of the CVA50MX-1 / CVA50PMX-1 includes a set of 4
DIP switches which control both the pre-gain of the microphone as
well as the +48VDC phantom power.
The “Mic Gain” setting will adjust for the sensitivity of microphones by
different manufacturers beyond what the volume control offers. If the
microphone is generally too loud, select the “High” setting by pushing
both switches up. If the microphone is generally too quiet, select the
“Low” setting by pushing both switches down.
If you are using a condenser microphone req48VDC phantom
power to operate, slide both switches down. Otherwise, leave the
switches in the “up” position.
The diagram below is an example of a condenser microphone (requiring
phantom power) and is loud enough without additional pre-gain sup-
plied by the amplifier.
Low On
Mic
Gain
High
Phan
Pwr
Off
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3.3 Special Features
3.3.1 Signal Sense Technology
™
Stewart Audio’s Signal Sense Technology
™
puts the amplifier into an
Energy Star compliant sleep mode after five minutes of no signal being
detected on any input channels. The blue Power Indicator LED will go
off and the amplifier will wait for signal to be present again. Once sig-
nal is present, the amplifier will return to normal operation.
3.3.2 Microphone Ducking
The CVA50MX-1 / CVA50PMX-1 includes a ducking feature which al-
lows the microphone channel (Input 1) to talk over the other 3 chan-
nels. When a loud enough sound is detected on Input 1 it will lower
channels 2-4 by a set amount. Both the sound threshold to activate the
ducking (Ducking Sensitivity) and the amount the other channels are
lowered (Ducking) are configurable via knobs on the front panel.
To properly adjust the ducking you should first play a typical source au-
dio (song, movie, etc..) through any of the channels 2-4. Once this is
playing, connect a microphone to channel 1 and begin to speak at a
typical level. You should hear the source audio lower when you speak
into the microphone. Using a small screwdriver, adjust the “Ducking
Sensitivity” knob to set the sound threshold which activates the duck-
ing. Next, adjust the “Ducking” knob to set the amount the other chan-
nels should be lowered. Turning the knob all the way counter-clockwise
will mute channels 2-4 when ducking is activated.
