So the history of this amp is that it was a Hi-Fi unit, no schematic available. I have been gradually eeking out a guitar tone. It has been suggested that I tear it all out and do a Fender Circuit. I think the PI is not set up correctly and I am considering a Long Tail pair change out. The amp has quite a bit of gain as the first two stages are cascading into each other, hence the voltage divider at the output of the TS.
Here is the tone-stack. I replaced the 100k with a 1k to get it working.
If that schematic is accurate to the way it's actually wired (and the right side of lower .022uF cap is connected only to the wiper of the bass pot), you have a serious problem.
To begin, I'd suggest connecting the right side of that cap, the top of the 6.8k resistor and the CCW lug of the bass pot all together. The wiper of the bass pot, the right side of the upper .022uF cap and the CW lug of the bass pot should be connected together.
I'd also suggest changing a few values (in red), but start by getting the circuit wired correctly and see if that gets you close to something functional.
My error, I will adjust the schematic. I do have it wired as you suggested, but with the values shown. Except for the 1k slope R
In that case, I'm out of ideas. Not sure what might happen if one of the caps is several orders of magnitude away from the values shown but I can't picture any scenario where the 100k being reduced to 1k would improve performance.
Ok,thanks. I have a feeling that the unconventional PI might be creating a situation that is loading the circuit in a strange way (forgive my non-engineering term). I am drawing up a Long Tail pair PI to possibly impliment.