There's been a lot of variations to this circuit over the years. Here's a few examples:
View attachment 124821
Found this schematic online for the Marshall Supa Wah. This particular wah uses germanium PNP transistors instead of silicon NPN.
Not much different here, though the schematic symbols for the transistors are incorrect. Truthfully: there are only a couple of changes from the stock crybaby schematic here.
- 220nF coupling capacitors changed to 100nF
- 4.7uF "not a bypass" capacitor changed to 10uF
- The inductor value is not listed, but I've read that these are about 1.5H
View attachment 124822
Here we have the Colorsound inductor-based wah.
- Input resistor value increased from 68K to 100k
- No emitter resistor on Q1.
- Q1 is a BC184. Very similar to the BC108.
- Q2 is a BC167B. Dunno much about this one: gen purpose audio.
- "not a bypass" capacitor 10uF instead of 4.7uF
- Voltage divider on the output: eases the load on the circuit if something like a fuzz face is used afterwards.
View attachment 124824
Boomerang!
- Input coupling capacitor increased from 10nF to 47nF.
- Input resistor dropped form 68K to 48k? Assume thats a typo. 47K.
- Q1 collector resistor decreased from 22k to 10K.
- Q1 emitter resistor decreased from 470 ohm to 120 ohm.
- Resonant filter branch resistor increased form 1.5K to 4.7K
- One of the two 470K resistors has been increased in value to 1.5Meg, the other has been deleted.
- 620K resistor directly from 9vdc to Q2 base added
- 220nF coupling capacitors increased to 1uF
- 1K Q2 collector resistor deleted
- Q2 emitter resistor decreased from 10K to 8.2K
- "not a bypass" capacitor increased from 4.7uF to 6uF
- Parallel inductor resistance increased from 33K to 47K.
- Sweep pot changed from 100K to 25K.
