Mon Dec 20 14:17:48 EST 2010
Distortion board rev1
- No connectors or holes for in,out,GND,Vcc
- No output coupling cap.
- Feedback resistor hard to replace by pot. Also needs pot in
- No feedback cap
- Diodes are the wrong way. Together with the biasing this made
the opamp saturate. Fix: replace 100k R5 with 22k to bring the
bias point near 1/2 Vcc.
- Schematics wrong: the 2nd opamp is a ground following buffer ;)
- After different biasing, 10K from out to ground is necessary to
enable class A, only upper transistor in LM358.
- 1/2 ref needs regulation.