Why not like this, to use 10k pot for BOOST in parallel with 10k resistor? Thus the crackle will be more gentle, and all the other aspects of the circuit will remain the same? I don't have a breadboard at hand right now, but if anyone's willing to try this, please do.

What is the inductor value?

Is there any chance that someone saved those pages:
http://www.jhaible.info/compressor/jh_compress.html
https://multicornpedals.files.wordpress ... llower.pdf

Both are not available anymore...

I'm having problems with this - once it starts limiting, it also starts distorting the sound. Tried different optos, and NSL32 sounds the best, although it also distorts a little. What could be the cause? Which optocouplers did you, people, used? I tested all the vactrols I have with this circuit an...

Do you happen to sell PCBs for it? TTH or SMD?

kdude34567 wrote: 22K --> 680 (between 5.1V Zener diode & Vcc)
What did you guys finally come up with that fixed the issue?

I am figthing with this too, but I think that this resistor shouldn't be replaced. Try to leave it at 22k.