PRM2

Dual Passive Ring Modulator

PRM2 is a Dual Passive Ring Modulator. It is based on the Ken Stone Real Ring Modulator. The major difference are the audio transformers chosen. They have better spec's, but of course come at a higher price tag. The frequency response is 150Hz to 80Khz (+/- 1.5db). What really sets it apart is the input impedance is 10k and the output is 600. Because of this huge mismatch, it squashes the output and lends to a lot of rich harmonic overtones. The low end is increased dramatically. There is a trimmer at the input to better balance the overdrive for more classic ring modulation. The diodes chosen for the kits are hand matched 1N60's, but any diode here will do. Even LED's.

As this is a passive circuit, it is advisable to use a Buffered Multiple before the Audio Input to maintain amplitude. Especially if you wish to use this as a Real Ring Modem/Mod DeMod.

https://www.laurentidesynthworks.net/eurorack-diy.html