Fuzz Face Input Capacitor Mod

[paulrm]

I normally make my own pedals, last two were a OCD and Jordan Bosstone, both of which I chanced the capacitors because I like a bright sound. I have an Elitetone Fillmore Thunder fuzzface which as an input capacitor of 47uF and it sounds wooley and boomy with my strat neck pickup. I socketed the input cap and replaced it with a 100n, and to my ears it sounds much better. However, I've since seen articles on the miller effect and transistor gain, input impedance which I don't really understand.

My first question is, will my 100n input cap change the characteristics of my fuzz face too much or will it still behave like a proper fuzz face (cleaning up with guitar volume etc).

The pedal also suffered from severe oscillation with my wah, I can avoid this by changing the bias (has a knob), my second question is will the input cap make the pedal less likely to oscillate?

Without using a buffer is there anything else that can be done to prevent oscillation? Thanks.

[antonis]

Input capacitor has no significant effect on input impedance..
(actually, 47μF forms a series resistance varying from about 42 ohm at 80Hz to a couple of ohms at high frequencies which is negligible compared to the rest circuit resistance..)
Miller effect and Circuit gain are also independable from Input capacitor value..

I can't find any schematic of Elitetone Fillmore Thunder fuzzface but if it's a kind of "conventional" fuzz circuit then input cap creates also a high pass filter with base bias resistor(s) (that's the reason for hearing less bass by lowering it's value..)

IMO, oscillation isn't related to matching (or not) impendaces but don't take my word for this..