Cracking the fuzz factory

[Brownmatthall]

G.A.S. has come for me yet again, this time for the fuzz factory pedal that litters most muse records. After doing some homework on the pedal I read that the heart of it is 2 Ge diodes feeding into each other to create the chaos that its most known for, so i loaded up the bender fuzz with a feeback send and return feeding the signal out of the pedal and right back in. The results were a very thick woolly sound that once you turned, well ANY of the knobs past noon would send it into a noisy whir that very slightly changed pitch the more the knob went up. Besides the FB S/R I switched the clip type to Ge and set the bias to fully CCW in this clip with the oscillations being cause by the knobs on the drive followed by the level of the send and return blocks.

The clip was recorded silently through headphones so the feedback is probably significantly worse but within the next couple days I want to test different combos of the FB loop blocks and 1/2 drive blocks in tandem with the pitch and volume blocks on controllers. My hoping is that the seeds here will allow someone willing and much more capable than me to figure this sound out!

 

[mongey]

sounds cool . I have a older fuzz factory form when there was no power jack and they were all hand painted

thing about it is a fuzz factory doesn't sound like the same fuzz factory from day to day .its the most fineky pedal I own. it almost plays you

 

[mr_fender]

That's the germanium transistors. They drift a lot, especially with temperature. You can hold your finger on the little metal can cases and the warmth from your finger can audibly change the response. Silicon is much more stable in that regard.

 

[dr bonkers]

This is madness but this is cool.

 

[KG MD]

That's the germanium transistors. They drift a lot, especially with temperature. You can hold your finger on the little metal can cases and the warmth from your finger can audibly change the response. Silicon is much more stable in that regard.

We need an "ambient temperature" control in an advanced parameter page.

 

[barhrecords]

We need an "ambient temperature" control in an advanced parameter page.

A temperature sensor as a modifier would be cool

 

[komorebi_dayo]

Another challenge is that the Axe can't translate the variable output impedance of a passive instrument to internal processing. It was my dream for the longest time to play bass in a MUSE cover band and even now that I've got the awesome AX8 I still expect to run a couple pedals prior in the chain if that ever happens.

 

[mr_fender]

True. That's why the Axe fuzzes respond differently to changes in guitar volume and tone controls compared to the physical pedals. That impedance interaction is isolated by the Axe's input circuit. With all the parameters in the fuzz models and the variable input impedance, you can mostly recreate specific combinations of fuzz and guitar settings, but it won't respond to the guitar changes on the fly like the real pedal will. Many of the same tones are there, you just have to tweak them out individually in a different way. Part of the magic of the old fuzz face circuit is all the subtle "in between" tones you get when messing with the guitar controls. The way they can go from woolly spitting distortion madness to sweet glassy clean and everything in between with just a roll of the guitar volume knob. Of course that interaction depends entirely on the guitar and pickups used too. Given they are buffered, the Axe fuzz models do clean up surprisingly well. Most real fuzz pedals placed after a buffer sound like steaming crap, so Cliff has definitely done some wizardry there.

 

[StickMan]

Given they are buffered, the Axe fuzz models do clean up surprisingly well. Most real fuzz pedals placed after a buffer sound like steaming crap, so Cliff has definitely done some wizardry there.

Don't forget that the Axe fuzzes are digital models, not actual fuzz circuits. So having buffered or pre-processed input shouldn't be an issue. What I would like to see is a parameter to model rolling back the volume on the guitar, set up so that you can put an external controller on it and control it with an expression pedal.

 

[StickMan]

That's the germanium transistors. They drift a lot, especially with temperature. You can hold your finger on the little metal can cases and the warmth from your finger can audibly change the response. Silicon is much more stable in that regard.

There's a reason that Ge transistors were replaced with silicon transistors for virtually all purposes. No two units are the same, and they are very sensitive to environmental factors and their specs are totally crap for precision and hifi applications.

Silicon Fuzz Faces, on the other hand, make a sound that makes me feel like someone is digging into my forehead with an ice pick.

 

[mr_fender]

From Cliff in another thread: "The Fuzz in the Axe-Fx reacts as though there is a buffer in front of it (because there is). It's a limitation inherent to all modeling products. I modeled it using a nominal source resistance. I forget what I used for the source resistance but it was probably around 100K ohms. As you said to really simulate it you would need a controller to simulate the changing output impedance of the guitar."

It would be cool to have such a parameter. You could tie it to the input volume and more accurately simulate the effects of rolling off the guitar volume.

Silicon Fuzz Faces get a bad wrap. Some can sound like crap, but so can some germanium ones. The Fuzz Face circuit is very sensitive to transistor selection, so some units sound much better than others. Most of Hendrix's later work is silicon fuzz (tweaked by Roger Mayer) and those tracks sound pretty darn good to me. Contrast the rhythm tones of Purple Haze (Ge fuzz) to Bold as Love (Si fuzz). Amp settings have just as much to do with it as the fuzz itself.

 

[Fatam]

It is funny I run a few pedals into my axe and the fuzz factory is one, just for the, "I have no what it will do when I stomp on it" vibe. No idea how to do that in the axe though!

 

[StickMan]

Silicon Fuzz Faces get a bad wrap. Some can sound like crap, but so can some germanium ones.

The circuit is so simple that the only difference between a good Ge FF and a bad one is the transistors. Each Ge transistor is an individual, some are just crappy, and the two units in the FF have to be matched to each other. I think one person who makes a fair number of FF pedals says that he's lucky if he can get a dozen or so good matched pairs out of a batch of 100 NOS Ge transistors.

Also a couple of the resistor values have to be tweaked to match the transistors.

I also suspect that a hell of a lot of Hendrix's tone came from his fingers, not his gear. The rest of us should just stay away from silicon fuzz faces.

 

[Muad'zin]

David Gilmour used silicon fuzz faces to devastating effect on Pink Floyd albums from Meddle to Wish You Were Here, and on the Live in Pompeii vid. It's all over Dark Side of the Moon. So silicone seems just fine to me. Even if requires a little more effort to get a good tone, it beats having to deal with finicky germanium.

 

[dr bonkers]

If you need to simulate the variances of tone and drive based on the output of your guitar, it seems like you could tie one or both of those controls to eithe the dynamics controller and or the pitch controller.

The main thing though is figuring out the range and slope of the controllers for the range of sounds you want as well as if you want both controlls to increase at the same time or one to decrease while the other increases. Now I have to look when I have more time to see if the pedal bias and slew rate can also be tied to controllers, as that may yield even more unpredictable or guitar playing dependent behavior.

 

[jakbur]

Don't forget that the Axe fuzzes are digital models, not actual fuzz circuits. So having buffered or pre-processed input shouldn't be an issue. What I would like to see is a parameter to model rolling back the volume on the guitar, set up so that you can put an external controller on it and control it with an expression pedal.

That was my wish on Fractal wish list from maybe 2 years ago. At the time everyone said it couldn't be done but I'm sure it hasn't been a priority for Cliff or it would be done!