I've tried to build a Keeley compressor 4-knobs version. I followed these schematics http://i650.photobucket.com/albums/uu229/MNhutDevil/Keeley_C4_Compressor_schem.jpg http://tagboardeffects.blogspot.it/2012/07/keeley-4-knob-compressor.html
However this compressor works bad. Is sounds distorted and cuts a lot the volume. I tried to change the IC (I though that was broken) but the sound still distorted.
I recorded an audio track to show you this problem https://drive.google.com/file/d/0B5KZd_ISqamrZll3WTI5TldWODQ/view?usp=sharing.
I'm desperate, this is a birthday gift!