Summit Audio 2BA-221 Mic and Line Preamplifier - Manual (Page 6)

Front Panel
6 Summit Audio, Inc.
Pad Switch
This switch engages or disengages a –20dB pad to set the
input sensitivity of the microphone input. If enough gain is
available with your microphone, use with the pad set to –20
for quieter operation.
Polarity Switch
This switch inverts the polarity of the microphone input in
order to compensate for out of phase equipment or wiring.
+48V Phantom Power Switch
This switch enables +48 volt phantom power to the micro-
phone input. Phantom power is present whenever the blue
LED is illuminated. Turn the unit off to bleed off the voltage.
Warning: Some microphones cannot tolerate phantom
power and may be damaged. Check the microphone’s specifi-
cations and requirements before using phantom power.
Highpass Filter Frequency Control
This control adjusts the frequency of the highpass filter from
20Hz to 200Hz. The highpass filter is used to remove low
frequency rumble from the mic input.
Important - Please Read!
The 2BA-221 contains a vacuum tube which
generates heat.
Do not block the cooling holes on the top of the
2BA-221 and always allow adequate ventilation
when mounting the unit in a rack enclosure.