Bit By Bit Boneyard Breakdown

[oldhousescott]

You're absolutely correct. The cap passes highs to create a filter that passes lows! Where's that smiley that bonks himself on the head with a hammer? 

[shawnee]

So if C4 is part of a filter, does that mean that switching from the 100K crunch pot to the 1M hi-gain pot is going to change the frequency? It sounds like the bass is more pronounced when playing in hi-gain mode to me. I also thought that I could compensate by replacing C4 (330p) with a 33p cap for use in hi-gain mode and switch in a 300p cap in parallel using the extra lugs on row A of the 3PDT crunch/hi-gain switch. I figured to get the same frequency at 10 times the resistance I would need to cut the capacitance by a factor of 10. Am I on the right track?

[oldhousescott]

If both pots are turned full CW, then yes, the filter corner frequency will shift by 10 times. In this case the corner frequency will shift from 4.8kHz down to 480Hz which will seem like an increase in the bass response. Offsetting that cut in the highs should be a greater amount of highs coming from the clipping LEDs as the gain is turned up. You might be better served trying to find a compromise value rather than switching in an additional cap, although that's certainly an option. Alternately, you could reduce C4 to 47pF or so and add a cap from the junction of R6 and C6 to ground to provide a fixed frequency high-cut.

[shawnee]

Thanks Scott! I was wondering how that would work when trying to compensate for another pot since the resistance can change so drastically. I thought maybe switch in the cap to get the same frequency with both bots at the mid point. Of course it would have to be tone tested to see how it sounds.
I am not sure I understand where to insert the cap you are talking about with R6 and C6....