Hi I'm new and: Fuzzrite stuff

[sunder]

Hi,

I'm new on this forum. Short introduction:

I'm 29 and have played guitar for 20 years now. Got into building/modding some years ago. I've been lurking here now and then, and now I hope I can contribute something to the community.

Fuzzrite... I have built a clone with BC108 A transistors and messed around with some values. Here are my findings.

The BC108 seems to have been a lucky choice for this; it seems to sound really good, not much gain really but nice breakup and texture. I found out that the original TZ82's were small signal silicon NPN's (on the American Semiconductors page IIRC), so I grabbed these (leftovers from fuzz face experiments).

I used 470 k resistors on both collectors, which sounded OK but not great. I then tried 4k7 resistors and the unit got really loud and noisy. With the 4k7's I measured  ca. 6.5 v on Q2's collector, that seems to have been too much...

Right now I have 68k resistors in there and it sounds just right. Most of the noise is gone, it has a little better bass response (...?) and it sounds a little "tighter". I measure under 1v on Q2's collector, a little over 1v on Q1.

I used a 22k volume pot and a 470k fuzz pot, just because that's what I had in my scrap box. The caps are .0022 and .047 sizes. I might play around with them to get a little more bass, although that may take away from the midrange buzziness...

The overall sound is bright, ratty and 60's style buzzy. With my Tele and AC30 I came very close to the "Satisfaction" sound (as well as some "Sticky Fingers" style riffing). Satisfied! I didn't notice the octave up effect some of you wrote about, that may have something to do with the transistors? don't know.

It's a "character" fuzz for sure.  This pedal has sharp teeth.

[petemoore]

We used to live in Bitburg///I'll Never forgter living in the Eifel !!
 Really, a magical place !!!
 You've done some 'Homework' on this circuit!!!
 Those 470k's just never looked 'right'...I tried this one a couple times before I knew anything about biasing transistors, and got limited returns/nothing.
 I chose it at the time because of the schematic's unuasually symmetrical appearance.

[sunder]

Never lived in the Eifel, but my family stayed around Frankfurt for some time. Nice place, though I missed the water/beaches... Kiel is about 100km north of Hamburg (no, that's still germany, not Denmark) port town with ferries to Scandinavia, those ships are bigger than most houses here. (heh)

Fuzzrite: I had no 47k (might have tried them), but found some 68k and tried them.

Try it! It sounds cool. Very few parts, too.

I just drew an alternate schematic that doesn't show the symmetry. Looks a lot like a Fuzz Face without the feedback resistor. Of course, there are fewer components (even fewer) and the fuzz control works totally different. It's like a balance/blend control which mixes the output from each transistor stage. As you mix in the second stage, you get more gain (obviously) and more mids/highs.

It's really just two identical (and very rudimentary) transistor stages in series, with the blend control between the two outputs.