Great Soft Fuzz/Dist

[Nick C.]

Ironically, while messing with a light overdrive on my breadboard I accidentally knocked off the grain pot wire and discovered this great fuzz. No resistance in the feedback loop! Or maybe it's infinite? Really nice smooth and "creamy". Tons of sustain AND quiet too! Very controllable. Almost has a gating or trigger effect, but that doesn't affect smooth feel of the attack. No oscillation or runaway feedback. Input signal, pickup, volume, tone, picking have little affect, but very musical. I'm sure others have made this one too, must be a name for it. Great fun!

[knutolai]

isn't this what you would call a log amp? What opamp are you using?

this here stuff http://en.wikipedia.org/wiki/Log_amplifier

[Nick C.]

"isn't this what you would call a log amp?" Don't know, but that shows only one diode in an inverting stage.

Running  LTSpice, it shows the output with rounded peaks, due to the nature of a non-inverting stage where 1x the dry signal is mixed with the clipped. The sound is very saturated, and compressed, but not harsh.

What opamp are you using?"  TI RC4558 That could be a factor.

[knutolai]

Just noting the similarity. Soundclips would be awesome.

[nocentelli]

How different is it to having a massive, eg 10M resistor in the fb loop? Usually once you go very high it stops making much audible difference in the amount of fuzz, I just wonder if a large resistor is a different sound, more stable, less stable, noisier/quieter, more consistent with different chips etc.

[Gus]

I posted this some time ago


You can find a EH muff fuzz schematic in schematics (a link at the top of the page)
http://www.montagar.com/~patj/mufffuzz.gif

[Nick C.]

Muff Fuzz. Yea that's basically it with a boost in front,  inverting stages and different filtering.  It's so simple, so easy just to accidentally make it.
Gus, I was thinking of trying an adjustable bias too to get a brassy sound.

knutolai, I tryed it with a 1Meg and it just wasent as saturated.

Just played it now and I see that there is a slight gate, which is why it's cool to me. It keeps the noise really low. Rub the strings with my finger produces a very slight sound out of the amp. Light pick and your maxed out. Almost a Shmitt trigger?

[knutolai]

knutolai, I tryed it with a 1Meg and it just wasent as saturated.

wrong user 

[Nick C.]

Oops.

I forgot to mention my plan is to continue to develop the overdrive and then build it with a switch to put it into Fuzz mode.

[Nick C.]

Gus, if I understand yours design, you've got a bias pot that is labeled threshold-gate. How well does that work? I ask because I plugged other guitars into this and the response changed unpleasantly. Gating, glitchy, oscillations, yuck. Ok, some people like this, like Jack White, but not me.