Fuzz bottoming out...

[petemoore]

  There's a parameter.
  You cross it.
  The circuit misbehaves.
  Hopefully that misbehavior can be cajoled to behave in a certain way..or at least that was the default goal that somehow became the target sound...pressed to misbehaviour with some predicatable behaviour.
  Or...'how' that line is crossed, which of course depends on which line or lines...
  Just tweeking bias...
  Just dropping PS voltage
  Just Boosting input signal and bass
  Tweek your brains out, don't forget to make knobs where they need be and tweek the old knobs too, see if you can get it down to something reliable and then simpler? million options.

[gutsofgold]

well that was my first idea...larger input cap. the stock is 2.2uF on a fuzz face so I upped it to 22uF which is what Fulltone uses in their 70s fuzz pedal. it didn't really do much 

[Gus]

With FF types try different value feedback resistors check/write down your operating points and note the changes in sound.

[caress]

higher gain transistors, slight misbias, larger input caps, change the voltage feedback resistor?

[doug deeper]

yeah i agree with up the input caps and or any coupling caps in pretty much any circuit far enough and you will be shaking hands with the avalanche effect! (not really, but ive always wanted to call a pedal that)
but the extra bass with make that sound happen pretty quick! 

[earthtonesaudio]

If increasing the input cap didn't change things much, then the next step would be increasing the feedback cap.  The value of that cap partially determines the input impedance, and a higher input impedance will let more bass into the first transistor.  After that I'd increase the collector resistor on the first transistor... then on the second transistor... but by that point  you might as well have started with something from here:

http://www.geocities.com/tpe123/folkurban/fuzz/fuzzyfaces.html

...Particularly the MOS-based ones.

[waveman]

If increasing the input cap didn't change things much, then the next step would be increasing the feedback cap.  The value of that cap partially determines the input impedance, and a higher input impedance will let more bass into the first transistor.  After that I'd increase the collector resistor on the first transistor... then on the second transistor... but by that point  you might as well have started with something from here:

http://www.geocities.com/tpe123/folkurban/fuzz/fuzzyfaces.html

...Particularly the MOS-based ones.

Yeah my first Fuzz Face does this sort of sound... I used 4.7uf input cap 47k resistor off of transistor 1, 22k off of transistor 2, and 2.2k between the two resistors, along with a .1uf output cap. I'd bet if you made the input cap 10uf and increased the resistor values even a little more, it would get you even more unruly.

[Pedal love]

I do something not so kosher. I use a larger capacitor and then I add a large (~1m) resistor across (parelell) to the input capacitor. That is a personal thing I do and probably not a great thing to do.

[John Lyons]

So this basically lowers the impedance and boosts right?
It seems like a full range boost. What is the effect you are getting with this one pedal love?
I can imagine what I think it's doing but though maybe you could comment further my good man. 

john

[gutsofgold]

If increasing the input cap didn't change things much, then the next step would be increasing the feedback cap.  The value of that cap partially determines the input impedance, and a higher input impedance will let more bass into the first transistor.  After that I'd increase the collector resistor on the first transistor... then on the second transistor... but by that point  you might as well have started with something from here:

http://www.geocities.com/tpe123/folkurban/fuzz/fuzzyfaces.html

...Particularly the MOS-based ones.

Yeah my first Fuzz Face does this sort of sound... I used 4.7uf input cap 47k resistor off of transistor 1, 22k off of transistor 2, and 2.2k between the two resistors, along with a .1uf output cap. I'd bet if you made the input cap 10uf and increased the resistor values even a little more, it would get you even more unruly.

I just did exactly this minus the 22k off transistor 2 (which I'm assuming is the bias resistor) I just left my trim pot in there. I also increased the feedback cap to 200k. It's REAL gainy now but still not bassy enough. I even plugged my bass into it and it won't do this bottoming out effect.

[GREEN FUZ]

Can you name a recorded example (track/song) featuring the type of sound you`re referring to? It might help to pinpoint the exact effect you`re looking for.

[waveman]

If increasing the input cap didn't change things much, then the next step would be increasing the feedback cap.  The value of that cap partially determines the input impedance, and a higher input impedance will let more bass into the first transistor.  After that I'd increase the collector resistor on the first transistor... then on the second transistor... but by that point  you might as well have started with something from here:

http://www.geocities.com/tpe123/folkurban/fuzz/fuzzyfaces.html

...Particularly the MOS-based ones.

Yeah my first Fuzz Face does this sort of sound... I used 4.7uf input cap 47k resistor off of transistor 1, 22k off of transistor 2, and 2.2k between the two resistors, along with a .1uf output cap. I'd bet if you made the input cap 10uf and increased the resistor values even a little more, it would get you even more unruly.

I just did exactly this minus the 22k off transistor 2 (which I'm assuming is the bias resistor) I just left my trim pot in there. I also increased the feedback cap to 200k. It's REAL gainy now but still not bassy enough. I even plugged my bass into it and it won't do this bottoming out effect.

Add another trim 10-20k trim or resistor in series with the trim off of transistor 2 and go back to the 100k feedback resistor and see if that gets you any closer. The 200k feedback resistor seems to rebalance the bias and make it more distortiony (which I love) than fuzzy...at least from what I have seen in my couple of builds.

[gutsofgold]

well I've been through this circuit more times than I can count, at one point I had a trim pot for every resistor in there. I've tried increasing the input and output cap values, increasing the fuzz pot cap, still nowehere near that effect. Lowering the voltage source to about 7.9v and having a Q2 bias around 3.3v somewhat replicates the effect but without the bass intensity I'm thinking of. I know the bass needs to come from the input because the sound is definitely a product of "overloading" the input/transistors.

Next step is building a LPB-1 or Hogs Foot at the input of this.

[John Lyons]

gutsofgold

Go to my sound clips page and listen to:

Octave Up Sickbox
Orpheum

Are these similar to the sound you are looking for?

http://www.mrdwab.com/john/soundclipspage.html


john

[alex frias]

I wanted to thank you a long time ago for your soumdclips webpage, because it was a huge and helpfull contribution for all of us.

so I am going to use this trhead for that: thanx!

[gutsofgold]

the orpheum does it on the high gain clip!!! while it's not exactly what i am talking about I can bet if he just played the low E or a power chord off the low E it would do it. you can definitely hear it going on in the clip.

thanks john!

[John Lyons]

Ok, now were getting somewhere!
Cool, glad I could help.
Mess around with the Orpheum and see what you get.
It's a simple circuit and if you make the caps bigger you can get a bigger sound out of it.

Thanks for the knod Alex!
I sometimes wonder if anyone refers to the page...
Actually. I could host so clips for you if you want. Just short audio clips though...I only have dial-up modem service here 
If you send me the clips I can edit them as need be.

john

[GREEN FUZ]

I sometimes wonder if anyone refers to the page...

Absolutely. It`s great having a yardstick with which to compare one`s own builds. This seems like a good oppurtunity to ask, by the way, what happened to the Bosstone clip? Presuming there ever was one of course.

[John Lyons]

I put up the boss tone  heading but never put up a clip.
The boss tones I have made were with very high gain transistors or modded a good way from stock.
I have done some monkeying with the circuit and the only ones I have around now aren't stock so I wouldn't want to
deceive anyone... I'll have to put up some "stock" boss tone clips whenever I breadboard that one again.

If anyone has a clip of there's let me know and I can host it. Same goe's for any other circuit really....

john

[gutsofgold]

check this pedal out...

http://cgi.ebay.com/Basicaudio-Solar-Myth-fuzz-pedal-beyond-fuzz-face_W0QQitemZ190245165473QQihZ009QQcategoryZ41418QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

It has a blendable bass input, which I am guessing is a pot wired to somehow vary the input capacitance? Ex: you turn that pot and the input capacitance increases allowing more bass in? Think this would be worth an experiment?