Hello Steve,

a VCA is an electronic volume fader. Instead of the knob you are using a
control voltage. The A-132 is the most basic form of a VCA.

A (passive) mixer is several volume faders which sum up several input
signals into a single output signal. It uses real faders or
potentiometers with knobs. Sometimes there is also a knob for the output
level. The A-138 has four inputs with knobs and a knob for the output.

A voltage controlled mixer is the same as a normal mixer, but it uses
controlvoltages instead of knobs. (Doepfer does not have a real simple
VC-Mixer. The A-135-1 is a combination of a passive signal adjustment
and voltage controlled adjustment)


What might have you troubled is the A-130 and A-131. These are
combinations of a two channel mixer (with knobs) and the output level is
controlled by a voltage via a VCA.

And what might you trouble also: nearly each VCA module has also a knob
which provides a voltage, that is used to control the VCA. So from the

Florian