fuzz face attack control

[pat styles]

Hello.

A few years ago, I built The Fuzz Face onto my Beavis Board.  The FF circuit I built was the one that came with the manual. It used the BC109 transistors that he delivered with the kit.

The fuzz was noisy and not too stable, but about what I would expect from a bread-board layout job. However, there was something I really loved about it. It seems the attack of the picked notes was more abrupt and slightly percussive in a way I have never before or since experienced in any of my other FF pedals. Same with the Fuzz Factory - it also did not have this characteristic. I have heard some of the more insane fuzzes like Devi Ever and others make and some of them have some over-the-top sonic disruption. What I heard was not extreme like that, musical, but a little less smooth than I was used to.

I missed this so and I pulled out the old Beavis Board and built it again. And the sound was back. I love this, and I would love to figure out how I could get this into an actual constructed and soldered pedal. I have a couple FF, a Fuzz Factory, and a kit fuzz I could add this to. What I don't have is any idea what it is about the Beavis circuit that provides this slightly percussive sound.

You folks are the experts. Do you know what kind of adjustment I could make to a fuzz that would give me this sound? It would be even cooler if I could adjust the attack to make it more or less abrupt.

thanks,
.pat

[thermionix]

Is it just a difference between Si and Ge fuzzes?

[pat styles]

Anyone else have any thoughts? I would really like to learn how to control the attack characteristics.

[kaycee]

you might be able to recreate the effect by putting bias adjustment trims on both Q1 & Q2 collectors, 50k on Q1 and 20k on Q2. it will be easier with silicon transistors than germanium.

its difficult to know exactly the effect you are after, but from my understanding of it, you might try the tonebender mk1, the germanium version is a tricky beast, but I believe there is a silicon version which might be easier?

[Plexi]

Can you share the resistors and caps values are you using?

I'm 80% sure that the attack comes from the high gain of the BC109.

You can:
- Use bias controls, to decompress the transistors.
- Use 100k volume pot instead of 500k to have a bit more bright end.
- Reduce input cap; but this will produce more harsh sound...not good.

I tried severals changes in the FF circuit, and the most usefull was the bias in Q2, and 100k volume pot.
2N2222 transistors, to-18 and matched hfe (very very important thing to reach a "creamy" fuzz).

[Quackzed]

you might be able to recreate the effect by putting bias adjustment trims on both Q1 & Q2 collectors, 50k on Q1 and 20k on Q2.

i think it's likely that a bias pot on q2 especially will do this, at one side of 4.5v a fuzz gets more compressed then gated at the other it gets more attacky then blatty , if you got the bias juust right on the attacky / blatty side it would be a bit more percussive on the attack.
if you got the bias close to the right spot with a 20k you could use a more sensitive trimmer like a 1k ( or a multi turn trimmer even better) to dial it in more precisely to that spot. transistor gains will have some effect but imho theres a 'range' of bias that is a little compressed or a little percussive on the attack on either side of  the sweet spot when biasing up fuzzes that sounds like what you're describing, each transistor is a bit different and so copying resistor values isn't likely to get you all the way there, you'll need some kind of trimmer on q2 (and possibly q1) to get it  right at that spot.