Another "Help, my Fuzz Face is playing Banda!" Thread

[Ben Lyman]

I have already done the search and browsed countless outdated threads with people making Radio related jokes about the Fuzz Face circuit, but no real serious, helpful info.
One guy, a long time ago in a thread far, far away... he might even be dead now, but he said to attach a small cap at the input to ground. Several different values later, all I could accomplish was to dial in a perfect mix of KFBK News Talk with a Mariachi soundtrack, very entertaining but only for a minute.
What is the modern technique to cure this?
It is most prominent when I turn my guitar volume or tone controls down.

[Kipper4]

Is it boxed?
Have you tried a shielded input and output wiring?

[Ben Lyman]

It's in and Altoid Peppermint tin with aluminum shielding tape lining the entire thing, maybe that's not good enough.
I have not, to my knowledge used any special hookup wire at the in and out, so thanks for that, I never knew.

I just noticed it picks up RF with:
1) my stock Fender P-Bass
2) my strat w/Dimarzio Area (hum cancelling PU's)

It does NOT pick up RF with:
Stock Epiphone Casino w/P-90's

[ubersam]

It is most prominent when I turn my guitar volume or tone controls down.

This suggests to me that the input capacitance (not the input cap) in combination with the guitar's output impedance, is not enough to form a filter to keep out RF. Try adding a 10K input resistor in-line with the input cap. If that doesn't do the trick, add a small cap to ground after the resistor. A 22pF~100pF MLCC cap should work.

[Kipper4]

That may explain the 470pf to gnd  seen here


http://www.diystompboxes.com/pedals/axisfuzz.gif

[Ben Lyman]

Thanks guys, I will try all that later, right now a guy is on his way over to buy it for $15!!! LOL     
In the meantime, I have A-B'd it with my old red Dunlop FF, all stock and unaltered, and guess what... same results as my home-brew!
Nature of the beast?!?!?!?