Take a look around this research
https://www.marksescon.com/blog/2023/7/20/kintsugi
I built one from the PPCB board and also couldn't get it sounding quite right. I ended up following some of the research from Mark's site
I am trying to build a mosfet boost at the front of a Barbershop with this schematic. There is something goofy going on in my build, whereby setting the gain knob anywhere other than 0 causes the voltage at Q2 to go haywire (6.4V to 9.2V with sag off). I've reflown all the joints on the board...
I recently built one of these pretty much to stock with the only difference being this final BJT I used a 2n3904 in place of the 2n2222, figuring it wouldn't make much difference. However, it ended up having much less gain than another one I built with the 2n2222. How critical is this part or...
I want more of a scoop. I'm assuming messing with C8 and C11 will do some of that. The taper also doesn't have much change between roughly 9 and 3 o clock, it's all bunched up at the extremes.