Found Compressor schematic - Link!

[Michael Weidenauer]

Found a schematic for a simple audio compressor. Don't know if it is intended for use with guitar.

The link is:
http://www.titan.spaceports.com/~whitie/302schaltungen/240.htm

[Nasse]

I printed out the text, my germany skills are rusty but nice looking circuit from old Elektor magazine, perhaps year 1982 or so. Circuit should work but cant say anything about sound quality or attack/decay times and how this suits for guitar. Little distortion mostly does not do much harm for guitar signal.

Diode compressors have been used in recording industry and audio, and are still not too much discovered source for analog ideas for what keeps this forum alive. I have spent only few  moments fooling around with diode attenuator things, but I believe there is some potential for d.i.y people in those.  Just was diggin my archives and foud a treasure for this stuff- Practical Electronics September 1986 number in mint condition and including five pages article of using diodes as analog signal control, controlled by d.c voltage.

[Paul Perry (Frostwave)]

Another Eletor design! and yes, it would work fie for guitar (but a bit too much distortion for
a microphone, probably.As input signal increases, the diodes D3 & D4 rectify & control T1, sending more current thru
D1, reducing its dynamic impedance & thus reducing the output. (according to the article). Interestingly, this is a 'feed foward' compressor, no closed feedback loop here.

[Nasse]

Here is a trick to reduce distortion to almost nothing: Replace D1 with two series connected silicon diodes (1N4148 or 1N914), and do the same for  D2, connect a capacitor about 1 uf or 4,7 uf from between "D2" and R3 to ground. You may need to readjust R3, R6 values.  Works well, I have tested a similar concept on perfboard and worked good as voltage controlled volume control or tremolo.