Bearhug FET CompressorVerified

From the post

Jon Patton's Bearhug FET Compressor (Yeah! That's the same cool dude who demoed Valvewizard's Engineer's Thumb a while back!) As requested.

From Jon: The Bearhug is a (fairly) low-parts-count, quiet, tonally transparent compressor using only transistors. It can do subtle peak limiting or squishy sustaining, with a decent amount of boost (probably ~6-12db).

Notes & mods:

- The hold cap is the reversed 4.7uF. This sets the overall compression and decay. The 10K + 47K in parallel with the hold cap set the decay. Larger values may be used, but these were the most natural sounding overall.

- The High/Low switch is there for "more." A 100K instead of the 47K would provide a much more dramatic change.

- You can use substitute Schotkey, germanium, or other diode with forward voltage under ~.35v for the 1N60Ps.

- The best tone control for this circuit, if you want to add one, is Jack Orman's version 2 of Mark Hammer's SWTC.

- The 100pF cap is primarily to eliminate noise and can be adjusted to change the overall brightness.

Turned out pretty compact. I've been through it a few times, but you should still grab the schematic for reference from DIYSB...