futzing with the feedback resistor in a fuzz face

[mordechai]

So, I increased the value of the 100K feedback resistor between q1 and q2 to 150K, in my ff project, and I liked the result.  The sound had a little more "hair" to it.  Can anybody tell me what was actually happening to the signal as a result of this?  Just curious about the logic of the decision now that I know that I lik the result...

[Derringer]

if you raise the value of the feedback resistor, you will have less negative (canceling) feedback on the front end of the circuit
so you will have less distortion but higher gain from the circuit as a whole

changing this resistor will change the bias point on Q2's collector
so if you don't have a trim pot on Q2's C, the bias voltage changed along with the reduction of negative feedback which will also affect the clipping characteristic of the circuit

[mordechai]

Well, I do have a trimpot on q2, and I got it to sound just right.  It doesn't seem like I have less fuzz, though -- it still sounds really thick and sustains very well and seems like some frequencies stand out a bit more (in a good way...it sort of "screams" a little bit).