Hybrid Fuzz Face (Si-Ge)

Started by goo, October 16, 2017, 12:00:58 PM

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goo

I searched Forum and i found some things about better stability if Q1 is more stable (as Silicons are) and it does some effect on Q2 stability too.
I have some low gain PNP Si trannies, so i just want to figure out this kinda possibility of using low Si for Q1 and high Ge for Q2 - will it FUZZ? Shall it FUZZ with low gain Q1 Si (hfe around 30, PNP) and high gain Q2 Ge (hfe 250, PNP)? I mean, will it sound as fuzz and not as some overdrive/booster with low gain.
Thanx, guys.
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Fuzz-O-Rama

I cannot say how it will sound for sure but I strongly suspect it will not sound good and certainly not like an overdrive/boost. Just use transistor sockets and give it a try. I also suggest a potentiometer in series with the Q2 collector resistor for sure. I would suggest a silicon Q1 with a gain of around 120 and a germanium Q2 no higher than 180. These transistors are very easy to find. But by all means try what you have. There is a slight chance it might sound like an octave-up fuzz but I highly doubt it will sound like a standard fuzz. As long as you use sockets, by all means experiment. What do you have to lose? Nobody's watching!

GGBB

The idea of Si Q1 with Ge Q2 in a fuzz is nothing new or unusual, and is popular as the Joe Gagan Easy Face. I suppose that gains are the real question. Generally accepted guidelines suggest the neighborhoods of 70 for Q1 and 120 for Q2, but many great sounding fuzzes are made with much higher gains. Low gains like 30 are less charted territory, but fuzz land is like a wild west - anything goes if it sounds good. Try it and let us know.
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goo

i have some results. PNP trannies.
1. Q1 Si (hfe 30) / Q2 Ge (hfe 110-200) - not enough fuzz, kinda booster, low gain overdrive. And it is pretty hard to find "sweet-spot" resistance at Q1C/Q2C (i used trimpots and i tweaked them).
2. Q1 Ge (hfe 110-200) / Q2 Si (hfe 30) - that's pretty nice fuzzing thing. It does FUZZ. Temperature was at 19°C. Did not put it into the freezer or to some heater to check its stability  :icon_cool:
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pinkjimiphoton

goo, remember too that you can use higher gain si q's and adjust their gain downward in q1 by adding a resistor between e and ground.
if ya wanna lower the gain of a si q that's around 200hfe, try a 22r-100r e resistor. that will drop the gain down into the ballpark you need.
this is different from biasing. this actually "limits" the potential gain of the q, then you bias it from there.

i would socket them and play with them. there are MYRIAD combinations and tones to be had in various combos. once ya decide on what ya like, REMOVE the sockets and hardwire the devices in.

i know its heresy, but SOCKETS SUCK. great for testing, but COMPLETELY unroadworthy
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"When the power of love overcomes the love of power the world will know peace."
Slava Ukraini!
"try whacking the bejesus outta it and see if it works again"....
~Jack Darr

goo

2 pinkjimiphoton
thanx, man. for now i have no medium/high gain pnp-Si trannies (but i may make order with other stuff in future).
i'm a kinda couch-guitarplayer with no band (sometimes i play and record my trax by myself - onemanband'y, but again it's totally diy, no studio and cheap  :icon_cool:), so i can play at home with socketed Ge-Si fuzz (gt402i - 4GS1 (kt814g) which are in cyrillic ГТ402И - 4ГС1 (КТ814Г)).
it sounds nice and pretty low-noise, i mean REALLY low noise (i'll try to make some audio/video clip later).
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goo

#6
some audio.
recorded separately on two dynamic mics. vox pathfinder 15r with boost ON (gain and volume at 8 clock; fuzzface gain at max, volume at 1 clock)
no postprocessing, only converting to mp3.
https://drive.google.com/open?id=0B_LggB4L-uRiaHF0RmlKMHRQT0U
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pinkjimiphoton

i see two files bro, but can't open either one of them
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"When the power of love overcomes the love of power the world will know peace."
Slava Ukraini!
"try whacking the bejesus outta it and see if it works again"....
~Jack Darr

goo

#8
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duck_arse

I had to save the files to disk, but I heard them. clean up high, fuzz down low.
don't make me draw another line.

pinkjimiphoton

its a fuzzbomb, all right.

kinda gated for a FF. i'd probably try adding a small resistance between e and ground on that silicon. try a 1k pot temporarily, and find where it sounds best, and add a fixed resistor that's the closest you got.

to me, its overmodulating the ge. ya get a lot of fuzz, but its gated more. a fuzzface should have a better sustain, at least to me.

how does it react when ya roll the volume down on your guitar?

once ya find the "sweet spot" where ya can do it all from the guitar, you got it bro.

sounds good still, but i think you can improve it just slightly.

yeah, you can play with the bias of q1 too, BUT that doesn't lower the GAIN of the q. the e reistor will tho.
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"When the power of love overcomes the love of power the world will know peace."
Slava Ukraini!
"try whacking the bejesus outta it and see if it works again"....
~Jack Darr

GGBB

Jimi is the expert here, so I defer to his opinion, but I'll just add that the gating is probably why it is quiet. Without a certain level of input signal the Q shuts off the sound. I think one of the early tonebender variations did this on purpose and was known for being quiet. So a little gating can be useful if done right, but done wrong and you lose smoothness and sustain.
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pinkjimiphoton

gord is right. too much gating can sound kinda bad, but a little can sound great. i'm actually just learning about gating fuzzes, so i defer back to gord!!!
to me, the key is to get the "sweet spot" between too gated and too noisy. i built a weird fuzz recently with a gate, i think i posted it on the forum here.

it sounds great as what it is, but is completely opposite of what i was going for. ;)

in my case, where the fuzz  cleaned up best with the guitar knob, was right where the bias range was noisiest and most susceptible to all kindsa noises and rfi... even boxed!!
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"When the power of love overcomes the love of power the world will know peace."
Slava Ukraini!
"try whacking the bejesus outta it and see if it works again"....
~Jack Darr

goo

ok, thanx, i'll try to make some recording with more-sustain-fuzz after the tweaks.
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