The VCA-01 module is an amplifier with an initial level knob and CV control of the level.
The initial level knob sets the initial level of the amplifier.
The control voltage amount knob applies the CV socket input to the amplitude.
Control voltage input for amplitude modulation.
-Infinity db to 0 db (0 - 100%)
The initial level is typically set to zero (full counter clockwise knob position) and the amplitude is controlled by a CV signal which is typically an envelope generator.
If an input signal goes beyond 0db, it will hard clip which may introduce aliasing harmonics in the output.