Fever Pitch A wobbly delay

[ElectricDruid]

The way I'd read it is that the 2K2/1K divider reduces the StompLFO's output to 1/3rd of its usual 5V level - so about 1.66V max. Pin 6 sits at roughly 2.5V, and the current to ground sets the delay time. By altering the voltage at the bottom end of the delay pot, you're changing the voltage across it, and hence changing the current through it - at least, that's how I understand it.
I think I remember seeing schematics with a diode hanging off pin 6 to prevent current flowing back *into* the pin if the voltage externally goes above 2.5V, but it might not have been like that. Anyway, I think your little voltage divider might be an inspired solution to prevent the chip from freezing up or blowing up altogether.

If this theory is right, you ought to be able to tweak the voltage divider to get a bit *more* wobble out of it - push the max voltage up closer to 2.5V. But I don't know how close is safe or whether permanent damage results or whether it just freezes the chip like the start-up conditions.

Tom

[Kipper4]

The reason I didn't go below 12k2 series r between the lfo out and pin 6 is because in a previous project the lfo output was making a thump on the audio on certain waveforms.
I started out with a series 110k (inc the filter R. See above scheme) to get around this potential problem.
But hey ho the smaller k values where winking at me on the bench. "Go on try me."
So I went through progressively smaller until I couldn't see the point anymore.
It may be possible to adjust the wobble with the series R.
I don't remember.
Things can change quickly on my breadboard.
I've been through quite a few circuits since I got the first chip.
I had an idea to add a mfb filter in it somewhere......
So many ideas. I just need to up the ratio of winners to busts.

Thanks for the explanation Druid that makes sense.