A lot of people have the Big Muff kit from General Guitar Gadgets so I thought I'd start a thread on the mods people have done to them. Post which circuit you built (Triangle, Ram's Head, GGG-tuned, Russian, etc) and what mods you have made. And if you can, record a sample and post it. I'd like to collect ideas for future reference (I'm hoping to build the "Ultimate Big Muff" eventually). Here's a clip of my GGG-tuned Big Muff: http://soundclick.com/share?songid=7558089 Swapped out R18, R19 and C10. R18 is now a 100k pot in series with a 1k resistor, R19 is 10k and C10 is 47nF. Download the Duncan Tone Stack Calculator and you can see how different values in the tone stack with change the frequency response of the circuit. The Big Muff tone knob blends signal going through low pass and high pass RC filters.