Debugging Wampler Black '65 - very quiet and clean

[steffen]

I received the SMD J201s I had ordered, soldered 4 random ones among them to the adapter boards and used them to replace the J201s I had on the board.
I then re-adjusted the drain resistors to bias the new JFETs at about 4.5V and this time the resistance values were much lower (between 15K and 20K) and much more consistent. The result is that the effect of the circuit on the sound is obvious now, with even too much dirt when the boost mode is engaged, but nothing I shouldn't be able to fix adjusting the biasing (and/or tweaking the source resistors). Also, the signal at the output is much louder, with about 1V peak-to-peak when both gain and volume are maxed out and measured with the same probe as in my initial debugging. The sound does resemble the demos I have heard pretty closely and I am happy with the result all in all.
Too bad that I trusted the initial batch of J201s and didn't think of replacing them right away, but I learned tons of stuff along the way, also thanks to all of your contributions and insights! cheers