User Guide

4
with the PRO MPA II ” for more detailed instructions on setting the Input Gain control for the best
results.
Input Impedance control
This knob controls the Mic/line input amplifier impedance. This function allows variable voicing of any
microphone.
Refer to the application section titled “Adjusting the Input Impedance” for more information on making
the most of this function.
The ¼” instrument input is NOT affected by this control, and remains high (>1M Ohm) impedance.
Low Cut Filter control
The Low Cut Filter is a single tuned High Pass Filter that is frequency tunable. The input signal can
be filtered to remove “pops” or other extraneous low frequency information. This control moves the
rolloff frequency from 10 Hz (fully CCW) to 200 Hz (fully CW). Since it is single tuned, it preserves
some low frequency content so its use is less obtrusive. It is especially useful in close mic’d applica-
tions.
Gain switch
The Gain switch is used in conjunction with the input gain control to adjust signal levels through the
PRO MPA II. When depressed, the tube circuit provides 20dB more gain in the signal path. This also
has the effect of driving the tube harder and making the tube the dominant source of gain and over-
load character.