Fuzz input cap and resistor Question

[tungngruv]

I built a Boutique Fuzz (GGG). I'm using a matched pair of NKT 275's and it sounds pretty good. My  question is: will changing the input cap (from 2.2uF) brighten the sound up at all and will changing the value of the 470 ohm resistor increase the gain? Thanks for any help on this.

[b_rogers]

try a .1uf for the incap and try a 1m pot inplace of the 100k feedback resistor. then you can adjust the gain a bit. if you do this i believe you will have to tweek the bias..the boutique has adjustable bias pot right?



Brent

[petemoore]

I put 1k with lead length on top of board, then tag a 1k to that or not.
 Could be put on a switch. Doesn't seem to vary tone markedly.
 I change to 250k-500k output pot if output is low.

[tungngruv]

It actually has 2 bias pots (one 10k trimmer and then a 50k linear on the top of the box). From reading some posts, it seems that a 20-25k trim is better suited to this Fuzz cicuit. The .1 did help with better definition, but there was an overall volume loss. No big deal though, easily made up for that by turning up the pedal. replacing the 470 res. w/ a 330 or a 220 wouldn't add more overall "fuzz", would it? I did put the 1M pot in place of the feedback resistor on my multi face and it was pretty usefull. Added the "synth" sound  when turned clockwise. Around 10:00 and it was pretty much like a stock multi face. Thanks for your suggestions guys!!

[brett]

replacing the 470 res. w/ a 330 or a 220 wouldn't add more overall "fuzz", would it?

No, the 470/330/220 only affects the volume of signal, not any of its qualities.

Not surprising that the pot affected the results a lot.  Feedback and the hFEs of Q1 and Q2 are critical in this circuit.  Those high-gain tones can also be had with a higher hFE Q2 (e.g. a 2N3906) and the standard 100k feedback resistor.  Heck, the JH1 or JH2 (can't remember just now) had an MPSA18 for Q2 with a typical hFE of 800 :shock: .  Too high, really.  Every little nuance in your playing became a full-volume fuzz effect.

cheers