Here is what I found:
- R3 was 33K instead of 330K (I found it yesterday but it did not affect the motorboating)
- Today :
- there was a short circuit between C9 and R8 (I only saw it inspecting with a magnifying lens)
- I was using a swith connected to A B and two sets of diodes. I removed it an put Si diodes on the board
My guess is that the motorboating came from the short circuit.
Another issue: I expected the pedal to be very loud (like the transistor BMP) but it is not. With Vol and Sus to the maximum it just a little louder that when bypassed. Is it like this or I made another mistake?