Anyway, back on topic. In my experience, if you have RF getting into your pedal, there's not a great deal you can do. I've found that Ge trannies, particularly metal can's, are just plain old succeptible to interference, depending on the circuit. Fuzz Factories seem to be particularly troublesome for some reason. I know that some people have used ferrite beads on the wires right where they join the PCB with good results, likewise a small 22pf cap to ground on the input helps.
Most fuzzes that have this issue employ a common emitter gain stage, which is a really good way of making a simple radio receiver. If you want it to
not be a radio, you have to either stop the stage from rectifying the incoming signal, or reduce the gain at radio frequencies. Since the rectification is often part of the desired sound, the only remaining option is reducing the gain at RF.
One way that does NOT work reliably is to put a capacitor from the input to ground. In fact, when the OP turns his volume down, that's exactly what he has done. The guitar lead becomes a capacitor to ground at the input, and the result is he tunes in a radio station. The cap
does shunt frequencies for
some stations (which is why this is often suggested as a fix), but for other frequencies it may tune them in stronger. So it works for some people, some of the time, but it is not a cure.
Several things you can do to cut down generalized RFI: Adding a small input resistor and relying on the Miller effect can form enough of an integrator to bring the radio sound below annoying levels. If the resistor alone is not enough, consider adding a small cap from collector to base, i.e. making a more purposeful integrator.
