fuzz factory differences..wireing.

Posted by toolguy on Feb 18, 2015; 4:17am
URL: http://guitar-fx-layouts.238.s1.nabble.com/fuzz-factory-differences-wireing-tp17797.html

Ok..so my latest build (compact f.factory) is going "ok".
The oscillation is much wilder than on the videos..and the pedal is very hard to control. I either get Velcro fuzz (ie."walking on the sun" fuzz)...or hard screeching oscillation. I was able to tame it down a tad by adding a 8.2k resistor across the gain pot (just from experimenting) but all it really did was give me a tad more range on that pot. The noise seems to come more from the gain pot than the stab. In fact all the stab.pot does is control the frequency of the oscillation not stabilize it at all.
 Figuring I did something wrong...I had a look at the tag layout. the only big difference I see aside from it not having a few resistors (like the 1m input) is that the way the comp. and drive pots are wired. On the tag comp 1 goes direct to q3(E) and shared  with comp 2 and drive 3. Drive 3 then goes through the 47k to Q2 (B).  Where on the compact layout they all head to Q3 (E) 1st...then via a  jumper to Q2 (B). Is this accomplish the same thing...or does the circuit react differently in the tag version?

http://tagboardeffects.blogspot.com/2010/02/zvex-fuzz-factory.html

vs
http://tagboardeffects.blogspot.com/2012/10/zvex-fuzz-factory-compact-layout.html#comment-form
 
Also I thought (if possible) lowering the gain on Q (2n3904) might help...but I am not sure if adjusting the 220K on Q1 (b) would do that..and how it will effect things down the line.


 Don't know too much theory behind how the npn's work in a Fuzz (up for a good read though if anyone has a useful link or two).

 Thanks again for the help this week guys.

JD