Latest rev. Gator is contemplating further changes, but this is where I am today. The LM386 is gone; we're back to a dual opamp. Tone controls redone. The LM386 loaded the MID network too much and didn't do anything special for the tone. The MID control is cut only, centered at about 700Hz. The TREBLE control is a shelving filter, like the BD-2 TONE control. It cuts treble above 1KHz. The PRESENCE control is a variable-freq low-pass filter. At zero, it cuts off at 500Hz. At 10, it cuts off at 9KHz. With DRIVE below 5 (noon), the 2nd stage does not clip. Somewhere above noon, depending on the GAIN setting and guitar volume, the 2nd stage starts clipping.
Knobs (L-R): VOLUME - PRESENCE - MID - TREBLE - DRIVE - BASS - GAIN. I tried 5 different dual opamps: TL072, LM833 (installed), NE5532, CA3240, NJM4558.
TL072 sounds good, good output volume, fairly symmetric clipping.
LM833 sounds good, slightly higher output volume, nearly symmetric clipping.
CA3240 and NE5532 do not work well in this circuit. Very asymmetric clipping.
NJM4558 sounds good, good output volume, fairly symmetric clipping.
I used IR LEDs for the soft clipping.