Let's talk Fuzz Factory

[bumblebee]

Ok, Q1 is MPSA18(IIRC),  and the hFE for  the Ge trannies is: Q2 is 80-Q3 is 100.
These are actual zvex stamped germanium transistors pulled from a handpainted fuzz factory. (I had a nicer set I liked so i swapped them)

Hope it helps nail the sound for you easier!

[CynicalMan]

Awesome! I'll have to build one of these now (with some mods). I wonder how big of an enclosure I'll need to house all the knobs and switches...?
-Joe Hart

You can fit 8 knobs (+ battery, switch, DC, input, output) in a 1590B. 

www.diystompboxes.com/smfforum/index.php?topic=81026.0
www.diystompboxes.com/smfforum/index.php?topic=81026.msg670857#msg670857

[erix]

I made mine with a built-in with a battery eliminator..

I used a PIO .12uF between Q1 & Q2. Q1 is a 2N1973 (an old silicon NPN) w/ 158 hfe, Q2 is 2SA77 @ 60 hfe, Q3 is 2SB516 @ 103 hfe

Never played with a real one but this guy does some crazy stuff with the stab, especially with the gain all the way up.

ok,
erix

[joegagan]

gain mod - lets the user find friendly overdrive-y sounds and other softer flavors. i was lucky, i had omeg pots in 220k. never tried the more common 250k, should work.

[joegagan]

erix, that is a really pretty build. kudos!

[FisTheGoon]

gain mod - lets the user find friendly overdrive-y sounds and other softer flavors. i was lucky, i had omeg pots in 220k. never tried the more common 250k, should work.

Hi joegagan,regarding the mod,have you done it?Don't mind if you can upload for some sample?Very interesting

[joegagan]

hi, yes it is the 7th knob on the fuzzfact in the wah casing on page 1.

the pedal is currently out of order. will fix and make a sample.

[FisTheGoon]

hi, yes it is the 7th knob on the fuzzfact in the wah casing on page 1.

the pedal is currently out of order. will fix and make a sample.

Thanks. Hope to hear from you soon.

[joegagan]

reposting the images from p[previous page, sorry i moved them

[vendettav]

well i've previously modded Fuzz Factories and the best result was the fuzz factory with additional switch that'd give you a bit glitchy from time to time octave down! then i finally ended up with another mod and named it The Factory. tho didn't include that octave down mod.... I'd share how i did it but i yet have to go back myself and re do it and see if it really works

[mordechai]

I think I could use some clarification regarding the 10K Linear pot between the 470Ohm resistor and Q2.  What exactly is it doing, and what effect would it have in a "normal" fuzz face circuit?

[rousejeremy]

It would require somebody more clever than me to figure out the switching because I've been out of the loop for a while but the "swell" section from the Prescription Electronics Experience pedal works with the Fuzz Factory.
I've wanted to build a Fuzz Factory with a swell section for a while but could never figure out how to add the switch.
The problem is this. It will only swell at certain settings. Mainly, the volume of the Fuzz Factory has to be pretty much dimed. That means you'd have to turn the pedal all the way up when you want to use the swell section and remember to turn it back down when you don't because the pedal is freakishly loud. If there was a way to wire the Swell switch to bypass the volume pot replacing it with the maximum volume of the pedal diverting the signal into the Swell circuit (the Swell knob would be the new volume) it would be an awesome addition.
Here's what it sounds like

[Ben N]

... then i finally ended up with another mod and named it The Factory...

An unintended tribute to Lowell George, perhaps?

[vendettav]

... then i finally ended up with another mod and named it The Factory...

An unintended tribute to Lowell George, perhaps?

well idk really who Lowell George is. (may be a flame shield?) 
The Factory is actually my 3rd album's name i just released. (lol was that sentence correct?? )

[mordechai]

Let me try again, since I think my earlier question got lost in the shuffle -- what is the 10KL "gate" control actually doing to the signal between the 470Ohm resistor and the Volume pot?  Since this circuit has the Fuzz Face at it's heart, would the 10KL between the 470Ohm resistor and the Q2 collector have a similar effect?

[joegagan]

yes it would. keep in mind that in  this schem, what we usually think of as 9v is ground.  also, the way all the controls interact in the FF is a part of why the gate knob does what it does. also , the boosted signal from Q1 also plays heavily into this.

[mordechai]

the boosted signal from Q1 also plays heavily into this.

So in a standard FF then, the gate function would have a different "sound" because the signal lacks the additional gain stage at the outset of the circuit?

Looking back at the schematic, given the flip in polarity that you noted, I wonder if the "comp" pot serves a purpose similar to the additional resistor on the emitter-to-ground of Q2 on the YAFF.  Does it "open" or "close" the gain of that transistor?

[ugly_guitar_guy]

Here's one of the 3 FF's I've built. A friend of mine gave me an old morely volume pedal so I gutted it and built the circuit into it, with the "Stability" pot being controlled by the foot pedal. It's pretty badass to control the self oscillating pitch in real time, and when you duck it all the way back it gets really nasty and bit-crushed. I dig it.

The funny thing is that I don't know why or where things are different than the original FF, but the knobs do not respond at all like the Zvex model. I just turn them until i get something useable. It's a little more fun that way I think. I'll try to post a video of it some time soon.

Here's some pics:




 

[K Zustang]

Hi everybody,

I have built 2 nearly identical FF over the past months and one of them has a much fatter sound and goes into heavy territories much easier. The other sounds thin and also needs the STAB knob to be turned  lower than it should for oscillations to start creeping in. I switched between the two's Ge and 2N3904 and it didn't change anything. Q2 is about 60 and Q3 is 100. Both have very low leakage.

1. I thought of bumping the 100nF up a bit as suggested...how high should I go?
2. CAN anyone verify the GaussMarkov schematic or SABROTONE's layout or anything when it comes to pot lugs? It seems like every schematic is different when it comes to the pot configuration and I had mine corrected a million times until I believed I got it right (comparing to the original ZVEX video demo). It seems the SABROTONE layout is good but I am never sure about it.

Thanks,
D

[kodiakklub]

funny this thread popped back up. im in the middle of building my first one but waiting on the 128's from mammoth (they're backordered, sucks), though someone from the Czech Rep is selling "a fuzz factory pair" of 128's and a 3904 "as a bonus" for 15$ shipped. below is my version of the layout and circuit. only thing i changed is added an additional electro in parallel at the input and output to bring back some low end that is connected to a DPDT toggle switch. otherwise it's stock. it's not verified YET, but hopefully soon. feel free to give it a go.