I now created version 2 of the compressor.
This time I dropped the JFET input as this kind of pedal is used for live rather than recording and the sound difference is marginal.
Instead I upgraded the virtual ground to be able to sink/source some current and the envelope detector to use a full wave rectifier.
The gain reduction is now moved to the feedback loop of the gain op amp although I think it introduces some distortion. Theoretically it should have the same effect as shunting the signal to ground but somehow I feel that in practice it's not...
The LDR LED is not current controlled instead of voltage controlled which was made possible by the enhanced virtual ground.
It's bit more difficult to maximize the attainable gain with 9V rails with this device but I think I can get pretty close to line level.
I also tried using the 7660 voltage doubler but had trouble getting rid of the noise it generated on a tight vero layout. Possibly chokes on the rails would have helped but I didn't have any at hand.
This time I dropped the JFET input as this kind of pedal is used for live rather than recording and the sound difference is marginal.
Instead I upgraded the virtual ground to be able to sink/source some current and the envelope detector to use a full wave rectifier.
The gain reduction is now moved to the feedback loop of the gain op amp although I think it introduces some distortion. Theoretically it should have the same effect as shunting the signal to ground but somehow I feel that in practice it's not...
The LDR LED is not current controlled instead of voltage controlled which was made possible by the enhanced virtual ground.
It's bit more difficult to maximize the attainable gain with 9V rails with this device but I think I can get pretty close to line level.
I also tried using the 7660 voltage doubler but had trouble getting rid of the noise it generated on a tight vero layout. Possibly chokes on the rails would have helped but I didn't have any at hand.