. . . from EPFM (Electronic Projects for Musicians), by Craig Anderton. I made the circuit board for this one by pasting copies of the component layout and solder tracings on opposite sides of a piece of cardboard.
The internal trim pot that sets the carrier wave rejection is kind of touchy. Might have been better to mount it externally. If I listen carefully while not playing, I can hear the carrier oscillating very, very faintly.
Still, this is a great sounding ring modulator, with controls just like the very de$irable vintage Maestro Ring Modulator, plus an effects loop.