Yet another Fuzz Face question

[DryRoasted]

Well you wait for ages and then 3 fuzz face posts all come along at once ! 

I decided to have a go at a fuzzface because I've not made one yet and I got loads of Ge trannies sitting around.  I made a basic Fuzz face A-la RG Keen's schematic.  I biased Q1 to 4.5 V but no matter what trannies I used (AC 187 and AC 127) I couldnt get it to go past unity gain I rebiased each time  I changed trannies but at best I got a sort of farty sound if I really hit the strings, not the musical fuzz I expected.  Normally I would say I have dodgy trannies but they work fine in a Range master.  Other than replacing the 8.2 K resistor with a trim pot, is there any where else in the schem that benefits from tweeking?  I also replaced the 2.2uf and 20uf caps with 1uf caps cos I dont have any 2.2 or20uf caps at present, does this have a major effect on the gain/volume output?


I feel like a Noobie again lol!

Cheers in advance

[petemoore]

incap = HP Filter
33k biases Q1
470ohm, made as *1k boosts output more
100k FBLoop resistance
1k wierd taper gain pot, add series resistance to up gain, watch bias
Trimpot Q2Collector bias resistor, adjust for any Q swaps.
Socket Q's.
output cap =HP Filter
100k output pot is fine.
22uf made smaller uf value allows less amplifying of lower freq's.
See Fuzzcentral *Axis Face for LP Filter mod [cap across the 1k]
Pregain as in 'Easy Face with pregain control' knob
  I don't think I missed any "FF" Parts. Besides every part on the board, the trimpot is the only mod, also see ROG Multi Face, and 'technology of the fuzz face' at GEO..
  U might want a FF testboard, socketted Q's, caps, perhaps made to mod with a little bit bigger resistors than usual [you can always parallel another fixed R or even a pot to it, I left lead lengths above board on my FF Testboard for just this purpose] {a bit 'much' but I even made one once with all trimpots 'n sockets...
  FF's are highly variable, and respond with various gains using various transistors...may benefit from being slightly re-voiced...etc.

[tcobretti]

One of the things about this layout is that it is tight, so it's not as easy as it could be to swap components.  However, it is doable, and I have learned a ton in the last week or so since I built mine.  A couple of significant things I learnt: I used 47p caps on the transistors and it really kills the abrasive part of the treble if you use Si, and the 100k feedback resistor has a huge effect on gain (lower value=less gain).

[DryRoasted]

Thanks guys