Circulator Phaser "ring mod" mod

[zoots]

I just built a circulator and modded the range toggle to take the LFO into audio rate when in the middle position.
I put a smaller capacitor from the negative leg of C13 to the cathode of D100.
I don't know the exact value since I pulled it out of a bin of discarded parts, but I assume 0.1uf is fine.
The LFO stops oscillating when the rate knob gets to a certain point, but I didn't adjust the rest of the LFO since this gives you "stock" functionality at the top range of the rate knob when range is in that middle position

 

[Chuck D. Bones]

The LFO would be happier if that 100nF cap went to U3-8 instead of D100.

You can play that LFO game with any modulation pedal and get the ring-mod effect. The DEPTH knob is helpful because it lets you reduce the dissonant tones a bit.