#1
Hey guys, I recently ordered a fuzz face clone but it comes with silicon transistors and I've read that the fuzz face Hendrix used had germanium transistors, so I ordered some and will be replacing the silicon transistors (and making the appropriate mods), but I was just wondering if there were any differences other than reliability and temperature sensitivity/leakage.

I've heard gearmandude's shootout on youtube and the Ge one sounds a bit sweeter than the Si one, but are there any differences in sustain? Also, what are the differences between different Ge transistors?

I ordered a pair of matched low gain AC128s, but people say the AC188 are much better, and I think Hendrix used the NKT275s. I know there's low vs. high gain differences, but anything else? The sound I'm aiming for is low gain but lots of thick throaty sustain (and I want the sustain to oscillate at the end, any tips on that?) thanks!

btw, I'm playing an American strat into a Vox AC15 C1.

I have a Big Muff but it's too gainy and noisy (and has no mids - gets totally lost when I play with my band), and I have a fuzz factory which has no bass (too harsh and trebly) and I have issues dialing in a sound that mixes well with the band (but by itself is amazing). I just want a vintage fuzz that doesn't get too crazy but still holds its own in a band.
Epi Sheraton II or MIA FSR strat > wah Q535 > fuzzface > Keeley C4 > Qtron > Whammy > Liquid Chorus > Triboost > Hotcake > BigMuff > Small Stone > VolumePlus > SpaceEcho > Cathedral Reverb > LoFi > MemoryMan > BYOC vibrato > DD-7 > Vox AC15 C1
Last edited by cheeekens at May 10, 2011,
#2
to most people the hendrix fuzzes were absolute dogs. horrible sound.

most people like germanium because it sounds "warmer" than silicon. silicon can sound harsh (and germanium can get buzzy). there is definitely a difference and audiophools argue that if it has to be solid state, then it has to be germanium...

honestly you should go with what you think sounds better.

as far as getting "correct" transistors, you can use any PNP ge type for the vintage sound or silicon for the modern sound. people get way too hung up on type numbers...AC128 were just cheap low-quality generics anyway. there's no magic about them. in fact i built a good fuzz face using some cheap (and fairly common) old 2SB175 transistors. these can be found in lots of cheesy old japanese-made stereos.

what you should be worrying about is the gain (not hfe/beta, as that does not take leakage into account...and ge transistors definitely leak, and it gets worse in higher temperatures). basically, with ge types, simple hfe is not enough. you need to seperate the wheat from the chaff, so to speak. here is a handy device to do just that. it tells you the true gain of the transistor, and the leakage current (if you dont want to to any simple math, then it's just another hfe meter). to most people the ideal gain range is 70-100 for Q1 and 90-130 for Q2.

http://www.geofex.com/Article_Folders/ffselect.htm

also there are alot of people selling fakes and re-branded/new-production parts these days. beware.
Last edited by Invader Jim at May 10, 2011,
#3
ok thanks for the link! yeah I'm just starting to get into building and modding so any resources are welcomed. I've also read that switching out some of the resistors for higher values (sometimes double the original value) increases the bass response, which I think I will definitely try, but like you said, I just need to try different thing and see what sounds good. I'll keep an eye on the gain; the resistors I ordered are supposedly low gain, but I think this will require some experimentation nonetheless.

I also found this: http://www.geofex.com/Article_Folders/fuzzface/fffram.htm

very helpfull too. Thanks again! =)
Epi Sheraton II or MIA FSR strat > wah Q535 > fuzzface > Keeley C4 > Qtron > Whammy > Liquid Chorus > Triboost > Hotcake > BigMuff > Small Stone > VolumePlus > SpaceEcho > Cathedral Reverb > LoFi > MemoryMan > BYOC vibrato > DD-7 > Vox AC15 C1
#4
resistors dont have gain...

but yeah, geofex is a great place to learn from. lots of tech articles.

just fyi, fuzz faces are easy to build but quite hard to get to sound right (or good). you'll want to read up on transistor biasing. you may need to tweak the bias of the transistors. alot of times I've had to deviate from the original circuit values becasue the transistors would be biased too close to cutoff, giving a splatty fizzy ugly sound.

here's a good place to start...
http://www.williamson-labs.com/480_xtor.htm
#5
oh sorry I meant transistor not resistor (when referring to gain). Thanks again!
Epi Sheraton II or MIA FSR strat > wah Q535 > fuzzface > Keeley C4 > Qtron > Whammy > Liquid Chorus > Triboost > Hotcake > BigMuff > Small Stone > VolumePlus > SpaceEcho > Cathedral Reverb > LoFi > MemoryMan > BYOC vibrato > DD-7 > Vox AC15 C1
#6
When I build these I use variable resistors and then test a bunch of resistors to find an exact match. They very rarely measure at what they are labeled. Every single circuit is different...

My favorite that I built is an Si NPN version with 2n2222 and I think a 3904... I'd have to look at it. Its subjective of course but I've never bought into the Ge sounds better stuff... with my gear, they sound a little different, but not THAT different... not worth the cost of the NOS Ge transistors anyway...
#7
yeah I agree that it definitely varies especially how the circuit might work with other pedals in the chain or the amp. My fuzz factory sounded really sweet when I have a Valveking, but sounds horrible with my AC15, and it has to be the first pedal in the chain. My big muff is more friendly with other gear... I know they're different circuits, but I think the transistors (si vs ge) might have something to do with it?
Epi Sheraton II or MIA FSR strat > wah Q535 > fuzzface > Keeley C4 > Qtron > Whammy > Liquid Chorus > Triboost > Hotcake > BigMuff > Small Stone > VolumePlus > SpaceEcho > Cathedral Reverb > LoFi > MemoryMan > BYOC vibrato > DD-7 > Vox AC15 C1
#8
Quote by cheeekens
yeah I agree that it definitely varies especially how the circuit might work with other pedals in the chain or the amp. My fuzz factory sounded really sweet when I have a Valveking, but sounds horrible with my AC15, and it has to be the first pedal in the chain. My big muff is more friendly with other gear... I know they're different circuits, but I think the transistors (si vs ge) might have something to do with it?


I'd guess that it has more to do with buffered/unbuffered rather than transistor type. Get any old Boss pedal (don't turn it on, just leave it plugged in) and try it before and after your fuzz factory. Crybabys are very weird like this too.
#10
^oh yeah I used to have my pedals set up like in my sig and the wah wouldn't work with the fuzz factory, but a few months ago i put the fuzz factory first and it improved my set up a lot. Totally forgot about the buffers... my SpaceEcho and Visual Sound liquid chorus have a similar effect on other pedals (but not as noticeable as the wah)
Epi Sheraton II or MIA FSR strat > wah Q535 > fuzzface > Keeley C4 > Qtron > Whammy > Liquid Chorus > Triboost > Hotcake > BigMuff > Small Stone > VolumePlus > SpaceEcho > Cathedral Reverb > LoFi > MemoryMan > BYOC vibrato > DD-7 > Vox AC15 C1
#11
Quote by Invader Jim
to most people the hendrix fuzzes were absolute dogs. horrible sound.

most people like germanium because it sounds "warmer" than silicon. silicon can sound harsh (and germanium can get buzzy). there is definitely a difference and audiophools argue that if it has to be solid state, then it has to be germanium...

honestly you should go with what you think sounds better.

as far as getting "correct" transistors, you can use any PNP ge type for the vintage sound or silicon for the modern sound. people get way too hung up on type numbers...AC128 were just cheap low-quality generics anyway. there's no magic about them. in fact i built a good fuzz face using some cheap (and fairly common) old 2SB175 transistors. these can be found in lots of cheesy old japanese-made stereos.

what you should be worrying about is the gain (not hfe/beta, as that does not take leakage into account...and ge transistors definitely leak, and it gets worse in higher temperatures). basically, with ge types, simple hfe is not enough. you need to seperate the wheat from the chaff, so to speak. here is a handy device to do just that. it tells you the true gain of the transistor, and the leakage current (if you dont want to to any simple math, then it's just another hfe meter). to most people the ideal gain range is 70-100 for Q1 and 90-130 for Q2.

http://www.geofex.com/Article_Folders/ffselect.htm

also there are alot of people selling fakes and re-branded/new-production parts these days. beware.


This. So much. I've built a couple dozen Fuzz Faces with varying transistor types. My stash of 2SBXXXs sound exactly the same as the CV7003/OC44s I've used and the OC81 I've got lying around, provided the gain is similar and it's biased properly.

For the NKT type clean up, you want a Q1 with around 60hfe and a Q2 with around 70hfe. Leakage under 100uA is common with those but anything under 300uA is acceptable. They're just a little less stable with temp changes.

I'd also take a look into some of the Russian GT series germanium transistors. They're silicon/germanium hybrids with near 0 leakage, NKT type gains and they're real cheap and readily available on eBay. Plus they're NPN so can be daisy chained with your other FX. The only downside is shipping from Russia takes a while. But a bag full of good Ge transistors for $15-20 shipped is worth it.

You can also use low gain silicon transistors like the PN2369 as in Phillip Bryant's Axis Face.
E-peen:
Rhodes Gemini
Fryette Ultra Lead
Peavey 6505
THD Flexi 50

Gibson R0 Prototype
EBMM JP13 Rosewood
Fender CS Mary Kaye

WTLT

(512) Audio Engineering - Custom Pedal Builds, Mods and Repairs
#12
^have you tried Ge's with an hfe of around 30-50? I have some old Ge NPN's (don't remember the type number) and I set out to measure the hfe, and for most it is quite low (the hfe was too low to even make a wah pedal wah). I do have some that have "usable" hfe though. but i was jsut wondering.