Here's my take on the Big Muff Pi. I started with the "Green Russian" circuit and added some modifications that make it my most versatile dirt pedal. It runs the gamut from clean boost to full on fuzz. I used the Tagboard Effects layout as a base. I'll start with the modification that's not obvious from looking at it which is the tone stack, I modified the values to more closely match the original circuit and provide what I thought was a better response. As for the extra knobs and switches I'll run through them in order. Bias Knob This 100k pot replaces the 100k bias resistor on the 4th stage transistor, turning this to the right brings the value down and further mis-biases the circuit. This lets you get some interesting effects even if it's not the most useful. The further right the quieter your sound and the more gated it becomes, at the extreme settings you can get some truly weird noises where only your transients get through. Tone Wicker This ...
My ramblings on a variety of topics.