AD633 as Eurorack Ring Modulation / Amplitude Modulation / Bipolar VCA

Here is an AD633 ring modulation / amplitude modulation / bipolar VCA circuit. U4 is the X input, U5 is the Y input, the ratio between R1 and R2 sets the level of the offset of the Y input, and VR2 crossfades between the Y input and the DC offset, thereby setting the strength of the modulation and allowing some of the X input carrier into the output signal.

In the demo below, two STO modules are used to provide a signal to the X and Y inputs. The signals are swept through different frequencies and waveform shapes.