Fuzz Face hiss - Mullards AC128

[Silvio55]

Hi, some time ago I put together a fuzz face clone and a Rangemaster TB using some Ge trannies a friend of mine gave me. For the FF I used some NOS Mullards AC128, but not really tested them for leakage, just for hfe with the multimeter and assumed low leakage. I put the lower gain in Q1 and higher gain in Q2, don't remember the exact values but between 90 and 130 I think. I biased it and sounds great to me.
For the TB I used a jap 2sb175, lovely pedal, I love it!
The thing is my FF hisses noticeable more than my TB, and the hiss hardly changes with the fuzz knob settings, just a little bit more with the pot at max. It's still usable thou.
Is it normal? Or there's a hissy transitor there? Should I try with other trannies? Have a lot to pick from!
Thanks!!

[mozz]

Try swapping them q1,q2 if you have sockets. If you don't have freeze spray, try canned air upside down, that should pinpoint which is noisy.

[Silvio55]

I don't have sockets, but have freeze spray. I didn't know that trick! Will try it, thanks!

[BluffChill]

How exactly does the freeze trick work? I'm intrigued!

[idy]

Higher temperature increases gain and leakage in Ge. Under bad circumstances, this will heat up the tranny and...thermal runaway. Guitarists notice Ge fuzzes sound different on a hot day. Some are said to keep one in the ice box at the studio..

[duck_arse]

what are you power supplying with, and does either/both circuit have supply R//C bypasses?

[Silvio55]

what are you power supplying with, and does either/both circuit have supply R//C bypasses?

Battery only, just like the original.

[pinkjimiphoton]

welcome to the wonderful world of germanium. you may have to add some snubbers between b/c to try and tame it down a little. one or both of your transistors is likely doing it. if ya hold your iron near it, the tone will change... the gain going up as it warms up mak make the hiss go away... in that case, you may get away with a bias adjustment, but usually, its gonna be a compromise.

you may be able to get away with one sili too in a pinch if ya have something lower gain than the ge... you can go either in either socket wth good results, but i think ge sounds better in q2, personally.

one thing you can be sure of, is its gonna sound a bit different every time you play it. temperature, humidity, phase of the moon all seem to affect them. magical results literally happen with carbon zinc batteries, if you can find them. they'll last forever in a fuzzface circuit. mercury batteries, even better possibly illegal tho.

so ya may wanna consider adding a bias control like on mike/analogman's sunface so you can adapt it to different environments on the fly.
i've had to chuck 'em in a fridge during hot days outside, and used to travel with an embossing tool to blow heat into them during cold months... would get me thru about a half a set either way

anywho, try the smallest caps you can stomach for the snubbers. if it makes it too dark, consider adding a high pass filter to the input... say, maybe 10k-ish with about a 2.2n cap. that should let ya dial out a little "woof" and make it a bit more versatile... put it right inline with the input to the circuit. also will make your knobs on the guitar work a little better imho, bu try first as ymmv and probably should.

peas