Let's talk Fuzz Factory

[soggybag]

Thought I'd test the waters on the new change of policy.

Post your favorite Fuzz Factory mods.

I don't have any good mods. I have always wondered why it uses 5K volume pot? Seems low is this part of the mojo?

[joegagan]

lifted from my post on the other thread:

...typical input cap blend mod adds a world of dimension to that pedal. the .01 cap between q1 and q2 gets a 100k pot>3.3 uf cap paralleling the .01. it's a beautiful thing.

my other favorite mod is to put a germ npn in place of the si q1. softens up the tone in a really pretty way.

other thoughts:

-if a high gain signal is fed into the FF ( zach has said all along the guitar should plug straight into the ff, i agree mostly, but have also gotten awesome sounds by placing other things in front of the ff), one may find that a 50k pot might be a nice replacement for the stab control. have not tried it specifically on a FF, but based on other experiments, the 5 k stab pot may not gate large signals as effectively as a 50k.

-i built a twinT wah that interfaced with a fuzzfactory. after much experimenting, i found the twin t to interact much better than an inductor type. will go find the schem and post here.

[John Lyons]

Make the input and output caps larger = bigger sound.
The way the circuit works (reversed PNP in a neg ground circuit)
and how the volume is tapped is why the 5K works.
It's a Fuzz Face as heart but with some clever trickery.

EDIT
Interesting about the twin t circuit in there Joe...
I'd like to see that.

John

[joegagan]

john, i have seen guys over the years talk about putting in and out caps larger than the stock 10 uf. i don't think they need to be any bigger. the key to the whole 'bright' image that the fuzzfactory has had is the .01 going into q2. change that to larger, and you have a whole new animal.

re: the twin t - having to go back and study what i did. i was remembering wrong, the twin t was inserting ahead of the entire ff circuit. BUT i switched simultaneously with the 100k10uf cap sweep ( referred to above) that worked in tandem with the twin t on a dual gang.

[boogietube]

OK, so I have a question... What should the HFE be for the AC128'S ? Banzai has them, but in many ranges.

[joegagan]

i swapped in different 125 hfe ( using rg's method) germs for q3 with good results. never played around with q2.

[soggybag]

I read somewhere Q2 = 90 hfe and Q3 = 120. I just used what I had and everything sounded OK. It might sound better with more carefully chosen transistors, I was working with what I had on hand.

I tried it out with Si transistors for Q2 and Q3 and sounded OK also. Though it didn't get that Ge sound. I think of more as a different sound rather than sound bad or wrong.

[John Lyons]

john, i have seen guys over the years talk about putting in and out caps larger than the stock 10 uf. i don't think they need to be any bigger. the key to the whole 'bright' image that the fuzzfactory has had is the .01 going into q2. change that to larger, and you have a whole new animal.

re: the twin t - having to go back and study what i did. i was remembering wrong, the twin t was inserting ahead of the entire ff circuit. BUT i switched simultaneously with the 100k10uf cap sweep ( referred to above) that worked in tandem with the twin t on a dual gang.

Joe
I see what you mean now. But .1uf not ".01".
That does make sense as the input cap blend
is a crucial element to a FF build (IMO).
Yeah, 10uf is plenty big in the input/output,
just bump that .1 up andit's fat city
Never tried the in out cap thing on the Fuzz factory
I just remember people talking about the 10uf
caps being bumped...but that's not really an issue
now that I look at the schematic...
Don't listen to me

John

[joegagan]

ok, let me see if i can explain this. there is a twin t wah
( basically the twin t circuit shown at geofex 'technology of the wah' article, with a few minor component tweaks that i can't remember)
that gets switched via a 3 pole 2 position rotary switch. this takes the circuit from non-wah'd fuzz fact to wah'd fuzzfact.

at the same time the wah is on, a large cap input cap sweep blend (within the ff circ) is also switched on.
the pot for the wah and the pot for the input cap blend are on the same wah shaft, being actuated together.
so, at the same time there is a wah input sweep going on, there is a cap sweep that keeps adding more low as the wah gets higher. it is very trippy
the harmonics are clashing and crashing, and the already crazy fuzz circuit does not know what to do.
every eighth inch of pedal travel is a new world.


if you check it out, the switched pot/secondary pot on the input cap blend is only active when the wah is in the off position.
i did not want to redraw or repost the entire ff schem, so i only showed the affected portion, Q1 and Q2.



there is one other very useful mod to this particular pedal that i will post later, i have to trace what i did so i can accurately describe it. as a teaser, i will tell you that it is a pregain control that allows the fuzzfactory to go much more into the overdrive/ soft distortion territory.

[joegagan]

thanks for the clarification, john. .1 it is.

[Processaurus]

I like the Stupidly Wonderful Tone control on my clone.  It originally had a BMP type Lo pass/Hi pass panning tone control but i couldn't get a usable sound out of my big amp playing live.  In addition to the SWTC there are some switches on the side, one, on puretube's suggestion, brings in a cap strapped across the pot, to get treble bleed and make the  tone control a odd sort of mid scoop.  The other switch changes the output cap from stock (bassy) to a smaller one (70's midrange flavor) or to a tiny one hooked directly to the output (it lost too much volume in front of the SWTC) , for thin radio sounds.  The latter is one of my favorite sounds.  I'd show how to do it, but they aren't intuitive controls, though the sounds are good.   

Also it has a photo cell in parallel with the stab pot, but it hasn't gotten a lot of use unfortunately.  Some other dynamic control of it might be better.

The original is a really classic pedal design.  Musicians I've lent mine to have really liked it, and recorded some creative sounds with it (especially multiple overdubs with different settings).

[dukie]

Soo now we can talk about "The Fuzz Factory"?
Well i never had luck with any of Fuzz Face circuit out there, too much mojo in it i guess  . i mean its soo simple circuit but i just cant make it work, its squeal, motor boating, noises and all of them ends up in my trash bin. So i never bother to try the famous ZVEX Fuzz Factory and since it was forbidden to talk about it here discouraged me even more.

But the itch still there and now the tide is turn ashore bringing new waves of policy and knowledge, i better grab my  perfboard  and surf in the sea of fuzz!
So help me guys... do you  have any link to FF schematic and layout?

Cheers!

[bumblebee]

OK, so I have a question... What should the HFE be for the AC128'S ? Banzai has them, but in many ranges.

I have a set of ZVEX Ge trannies here I can measure them if you want?!?!?!?!

[knealebrown]

Soo now we can talk about "The Fuzz Factory"?

So help me guys... do you  have any link to FF schematic and layout?

+1 for that, would be nice to build a clone. Thanks mr Vex

[John Lyons]

Joe
That looks really cool. The dual Twin t/cap blend sound like it takes it to another world.
You're the master of the dual pot 

Here the schematic for the Fuzz Factory as redrawn by Gaussmarkov.
This one is a lot easier to understand than the others I have.

[CynicalMan]

I'm working on a BMP style tone control, to be attached to the output of the pedal.

Code Select Expand



            68k
     |--- \/\/\/\-------|
     |            |     \
     |        6n8 =     / 50k lin
     |            |     \  <--------- Out
     |           ///    /
------|                  \
     |   6n8            |
     |---||----|--------|
               |
               \
               /
               \ 47k
               /
               |
              ///




It's designed to not take away too much signal, but a bypass control can be implemented by connecting a spst switch to either end of the tone control. I might be adding a mid scoop switch too.

Also, I would suggest adding a filter cap of 10u to 100u between power and ground. My breadboarded version sound horrible without one.

[boogietube]

OK, so I have a question... What should the HFE be for the AC128'S ? Banzai has them, but in many ranges.

I have a set of ZVEX Ge trannies here I can measure them if you want?!?!?!?!

I'd love to have the numbers. Thanks, man!

[bumblebee]

Ok I'll check the hFE today sometime.

[CynicalMan]

I'm working on a BMP style tone control, to be attached to the output of the pedal.

It's designed to not take away too much signal, but a bypass control can be implemented by connecting a spst switch to either end of the tone control. I might be adding a mid scoop switch too.

Also, I would suggest adding a filter cap of 10u to 100u between power and ground. My breadboarded version sound horrible without one.

OK, here's the scoop switch:

Code Select Expand


                       10n
                   |---||----|
                   o         |
            Scoop   \       ///
                   o
                   |
             68k   |
      |--- \/\/\/\---------|
      |            |       \
      |        6n8 =       / 50k lin
      |            |       \  <--------- Out
      |           ///      /
------|                    \
      |   6n8              |
      |---||----|----------|
                |
                \
                /
                \ 47k
                /
                |
               ///




[Joe Hart]

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