see the back of it

This is ballanced modulator, named usually as ring modulator. Based on AD633 multiplier.

DRY/WET knob:

controlls mix ammount of modulated signal and input signal

AC/DC MOD/CAR switches:

change coupling of modulation and carrier input respectively between AC and DC-coupled

MODULATION knob:

attenuator of modulation input

CARRIER knobs:

attenuator of carrier input

INPUTS:

MODULATION, CARRIER

OUTPUTS:

OUT