Silicon Fuzz Face issues or not?

[selfdestroyer]

I just built a small Si FF using this build doc
http://music.codydeschenes.com/wp-content/uploads/2013/12/Fuzz-Face-Silicon-Espanhol-Transfer.pdf

It went together just fine, and I know what your thinking.. "stand up resistors.. but why?" I just wanted a tiny etch-able build for a 1590B multi-pedal. So it fit the bill.

I used a pair of BC237's I had laying around with Q1 HFe 281 Q2 HFe 330 and I get really cool/brutal fuzz (which I like) at full gain. But I notice when I roll the gain back I also loose a noticeable amount of high end. Is this normal for a Si FF? I watched a few YouTube videos of Si FF clones but they all play them maxed gain.

Thoughts?

Cody

[Bret608]

That is very typical of silicon fuzz faces. I played a brand new Fulltone '70 in a shop once and it got pretty dull as soon as the gain was below, like, 95%.

Interestingly, I recently built up a hybrid ge/si version with the ge in Q1 and the si in Q2. Not only does it do volume knob cleanup better than an all-si type; I don't think rolling off the gain dulls it quite as quickly. Then again I haven't fooled around with it much below max gain. I did use bigger in and out caps, FWIW.

[JakeFuzz]

Yep the FF circuit tends to dull out a lot when the gain is down. Most people don't worry about it though as the volume knob roll off on your guitar at maximum fuzz sounds very good. A while ago I was playing around with ways to make it so you get a big bass cut when the fuzz pot was turned down. I cant remember the exact arrangement but the only addition was a single capacitor and it worked very well. I think it was a much smaller (10nF maybe) cap from the emitter of Q2 to ground but I would have to go back and check. Ill look more into it if you are interested in trying it out.

[selfdestroyer]

Thanks for the reply, I am glad that this is normal and I will take a look closer of the suggestions suggested. I may just remove the gain pot and make it "balls to the wall" and just use my volume knob. lol

On a side note, I may try a few other Si PNPs I had but the BC237's do sound pretty "wall of fuzz" and I just could not stop playing with it last night.