Crest Audio X-VCA Owner's Manual page 29

features
polarity reverse—ø
This switch inverts the polarity of the right input signal in relation to the left input
signal. see—mono input module for more info on polarity reverse
Polarity of the right input signal is inverted.
Polarity of the right input signal is not inverted.
input gain—
GAIN
This control adjust the gain of the input preamp(s).
Both left and right input signals are affected by this control.
stereo input module
2
p. 29