what does a "bad" Ge Fuzz Face sound like?

[alange5]

I've been playing around with the Fuzz Face for a while.  I bought a bunch of Ge transistors to experiment with, including GT308B, GT308V, ASY73, and NKT OC77.

What I've found through experimentation is other than the subjective preferences of the listener, I have yet to find a poor-sounding combination of transistors, as long as they are biased properly and don't have excessive leakage.  I pretty much stick to this formula: Q2 hfe about 20% higher than Q1, and no more than 400ua leakage.

Over the course of a day, I built three of them.

-#1 used low-hfe GT308's - about 55 for Q1 and 65 for Q2.  Both had just about zero leakage.  I'd describe the sound as "tight".  Very little excess noise, and a really nice cleanup (though rather abrupt). 

-#2 used ASY73 hfe about 100 for Q1 and 120 for Q2, both about 100ua leakage.  It was a bit more aggressive than the GT308's - a bit brighter and a little more "loose".  The cleanup was more gradual, and never got crystal-clean.  Still a very pleasing "clean" sound.

-#3 used OC77 with 70 hfe for Q1 and 90 for Q2.  These were leaky - about 300ua for each.  Sound-wise, it sat between the other two.  It had a really nice "bloom" and decay with a gradual cleanup.  Not too tight, not too mushy.


All three were biased to "traditional" fuzz face voltages, and thus, had different resistor values.  All three sounded different, but they all sounded really good.  I didn't audition a hundred transistors to land on these - I simply grabbed from the pile based on their measurements. And contrary to "mojo" rules, I think I like the low-hfe GT308's the best.

Which begs the question - what does a "bad" Ge Fuzz Face sound like?  Is a "bad" fuzz simply a mis-biased fuzz?  Or, when biased properly, does it all come down to subjectivity and preference? 

[GibsonGM]

I think it is a little of everything, alange...misbiased, leakage, subjective, and preference.    I, like you, have never  had a fuzz sound 'bad' AS LONG AS I tweaked the bias to where it 'was working the way it should' (to my ear), and adjusted bass and treble content via coupling caps (and a couple of other tricks).

I HAVE given up on a couple of designs that were (for reasons unknown to me, perhaps leakage....) unable to hold their bias...very temp. sensitive.  So maybe those transistors were just 'junk'.

[italianguy63]

I like the combo of the GT308V (Q1) and the GT308B (Q2) for a nice mellow fuzz.  If you can do it and can find them, my fav is a GT308B (Q1) with a MP20B  (must be a "B") in Q2.  Much higher gain combo and a great range from mellow to wooley.

MC

[alange5]

I like the combo of the GT308V (Q1) and the GT308B (Q2) for a nice mellow fuzz.  If you can do it and can find them, my fav is a GT308B (Q1) with a MP20B  (must be a "B") in Q2.  Much higher gain combo and a great range from mellow to wooley.

MC

The suffixes get confusing, no?  I built mine with Q1 GT308B (printed IT308b) and Q2 GT308V (printed IT308B).  I used a website with Russian character phonetic translations to decipher between the two.  The B and V distinction gets kinda blurry, especially on Ebay listings.

[italianguy63]

Yes.  It is confusing!  I was telling you because it is easy to find the MP20 or MP20A.  They are low gain.  You need the MP20B.

[a2music]

Once in a while I run into a Ge transistor that has lots of noise (sputtering and cracking) or radio interference due to a bad (objectively) transistor. Otherwise good or bad is in the ear of the beholder. The Tungsram AC125/128 which are available in large quantities from eBay sellers (mostly in Bulgaria and Germany) are passable but not great. I'd describe their tone as brittle and flat when compared to some Japanese, Western European or American brands. I bought some Russian P416 which sounded like crap no matter what I did to the bias. They sounded dull and lifeless. No rich harmonic overtones or complex tone pallet here. I have some to 2SBxxx (early 70s Japan) that sound fantastic in a fuzz face or a Tone Bender. I also have several different 2Nxxx that sound great. I consider one of the main determining factors in a germanium transistors' quality to be frequency response. You can make a great sounding fuzz from a couple of low gain Russian transistors (e.g. Q1=54 and Q2=71) with some but not others. I agree with Italianguy63 that the MP20B sounds great but I've also had good results with the other MP20 types (as well as IT308B).  I'm a big fan of low gain transistors in the Fuzz Face.


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