The Alfa AS3363 is not like anything else we’ve seen! Alfa describe it as a “voltage polarizer”, and we’ll go along with that, although in truth that is only one of the things it could do.
So what is it, exactly? The chip contains three separate VCA blocks. Blocks 1 and 2 are identical, and block 3 is slightly different. Blocks 1 and 2 provide an audio input and a “CV Mix” input which controls the level and polarity of the signal. Voltages from -2V to +2V will produce from 100% to -100% of the audio input signal at the output. This is a 4-quadrant multiplication of the Input and the CV Mix signal, so this can be used for ring modulation. There is also a more standard 2-quadrant Level CV which controls the final output from -2V to +2V for 0-100% signal. So each of blocks 1 and 2 is a ring modulator followed by a level VCA.
Block 3 is similar, but has two audio inputs, and the CV Mix input crossfades between them, allowing you to mix either 100% of Input A, through 50/50% to 100% of Input B. Again, this crossfade stage is followed by a standard VCA to control the final output level.
Supply voltage is ±5V to ±15V, so this can be be used with Eurorack +/-12V supplies or the standard audio +/-15v.