More questions on the lengendary FuzzFace.

[Burstbucker]

On the original vintage FuzzFace pedals, was the output capacitor a 0.1uF or a 0.01uF?

I know that the NKT275s are really good but what about the AC128 transistors?  If you get some good N.O.S. AC128s, are they as good as the NKT275 transistors?  Do they sound any different than the NKT275?

Last but not least, when they started making the FuzzFace pedals with silicon transistors, did they use the BC108C or was it the BC109C?  Maybe they used both?

[BD13UK]

http://www.geofex.com/Article_Folders/fuzzface/fffram.htm
If you haven't seen it before this is probably the definitive article on the subject

[Johan]

I got my F.F schematic from guitarplayer ( november -84 and containing errors...argh..) and it says 0,1uF so thats what I've been using.
I cant advice on the NKT275 becouse I never tried them, but i can tell you that if you get some GOOD AC128 ( and I've run into too many bad ones to be exited anymore..) you will have a F.F that is magic. going from cleanest clean to what you always wanted a F.F to be, feverish hot fuzz that is still full of defenition and together with a strat and a marshall will give you that same tone you can here on the "Hey joe" -solo Jimi played with his teeth at monterey...( ..oh, why did I give mine away?...oh, well..)

Johan

[Torchy]

crp

[leonhendrix]

looking on pete roberts website (he used to stock ac128 pairs) he says the ac125 (which he stocks) is the european equivalent of the nkt275

http://hometown.aol.co.uk/qgadgets007/germanium_pnp_fuzzface.htm

leon

[Johan]

You gave your teeth away ?
Did you kept the strat  :wink:

:lol:  ...I guess I could have phrased that a little better...
..and the strat is cursed...no, really..it's one i put together from parts, and everytime i disasemble it to replace a pickup ro refinish it or whatever, I get a lot of gig's ( part time musician..) and everytime it is together and playable, work just dry up, no one calls, no gigs, no monnie..and it's been that way for years and years..so now it just lays disasembled in the basement and I dont dare puting it together...what?..me superstisius?..NOOOO  :shock:

Johan

[phillip]

The most common output capacitor that was installed in the Fuzz Face was the 0.01uF.  I've heard of some 0.047uF capacitors making it into circuits, but the 0.01uF would be the one to use.  You can use a larger value like the 0.047uF and 0.1uF...they'll pass more bass and to me it sounds like it makes the circuit too muddy.  The input and output capacitors are really a matter of taste and your guitar and amp combination.

In all reality, there won't be much difference between the NKT275 and AC128 if you get a good pair with the "right" gains and low leakage.  Some say that the NKT275 sound different, and it's a possibility, but I wouldn't count on much of a difference.  They also used the SFT363E PNP Germanium.  Beware the "NOS" Germanium transistors on eBay.  A lot of them are actually generic new production Germaniums with NKT275 and AC128s stamped on the sides.  Here's a web page that outlines the differences between the old production AC128s and the new production AC128s (notice the difference in the size and shape of the metal cases):

//www.geocities.com/stompbox2001/ac128.htm

Dallas Arbiter and the later manufacturers of the Fuzz Face (like Crest Audio) used several different types of NPN Silicon transistors in the Fuzz Face circuit.  Some of them: BC108C, BC109, BC109C, BC183L and BC209C.  I believe all of those are still in production except the BC209C.

Hope this helps some
Phillip

[Eb7+9]

I know that the NKT275s are really good but what about the AC128 transistors?  If you get some good N.O.S. AC128s, are they as good as the NKT275 transistors?  Do they sound any different than the NKT275?

About eight-nine years ago, me and another long-time DIY'er I know bought NKT275's from a guy who had a biz selling "exclusive source" transistors and JRC4558 op-amps ... both of us have attempted maybe around 20 FF style clones each and traded our personal Germanium stocks to increase our chances of getting ultimate FF sound ... at the time Mike Fuller generously shared some tips over the phone which helped with WAH coupling and biasing (definitely one of the most helpful and knowledgeable old-school dudes out there !) ... we did go through our own small lots of AC128's and generally got good - but not outstanding - results no matter the tweaking ...

The special order 275's turned out to be not-so-outstanding to both of us also no matter the circuit configuration even though the seller said they had been tested in a real circuit and vouched to sound great ... we ended up finding other oddball Germanium devices that outperformed them ... I never found out if it was an accident or what, but the reply to my questions from the seller weren't solid so I dropped it ... the op-amps didn't sound like anything special in my stock and HiFi TS808 clones either ... that's just my experience with those few devices ...

A few years later, a young customer of mine decided to try his hand at building a simple fuzz ... we agreed a variable bias FF would be a great first project and I would coach him if he had trouble ... wouldn't you know it, he goes out and buys two AC128's from the local surplus shop (at $6 each) and he nails the most awesome FF tone on his first try ... the sound of his pedal remains to this day my FF reference ... his devices didn't test significantly different than anything I'd tried ...

There's something to be said about DC leakage specs but by the same token there's more than leakage specs to determine how sharp the transition edge of a clipping stage is going to be in a high-dynamic situation, how it goes from saturation into active again - at that boundary ... it's a known fact that the Base-Collector junction parasitic capacitance plays a role in determining how fast the device can go from one state to the other, especially if you're overcharging that capacitance ... regretably you can't do a DC test for this ... and then there's the issue of what happens to the Base transit times when that very thin Base-Emitter junction heats up ...

In this way it's not surprising to me there be so many posts asking for better FF tone even after doing Hfe or DC leakage testing and "recommended" device combinations ... with the "loose" nature of Germanium devices I'm of the opinion that nailing the HolyGrail comes down to some kind of divine luck - consistent with stories of Jimi's roadies going through boxes of these things ...

I never came close to what that kid did ...

so, I gave up ! ... :wink:

[phillip]

we ended up finding other oddball Germanium devices that outperformed them ...

You've had that happen too?  I couldn't believe that I spent good money on "specially tested" Germanium devices from Europe, and I ended up getting some wierd oddball NPN and PNP Germanium transistors from the college I was going to as they were housecleaning and planned on throwing them in the garbage.  So I carried them away for free and didn't think much of them since they didn't have any legible part number of manufacturer marks.  But once I tried them in a Fuzz Face circuit (without even testing them for gain or leakage!) my opinion of them changed.  

To this day I still don't know what part number those transistors are or who manufactured them...but those little beauties kicked all over those "magic" part numbers.

Goes to show that we shouldn't get caught up in the part number game

Phillip

[mojotron]

I don't listen to hype too much... I got really great results using an NTE102 for Q1 and NTE102A for Q2 and my ears like either .047uF or .1uF output caps. I started using the Boutique Fuzz schematic from GGG, went through a ton of Ge parts.. finally came up with the NTE combo that sounded like a pair of NKT275's without the hisssssssssssssss.

You will still need to buy 10 transistors of each.. only about 40% are usable...

[MartyMart]

I bought a "Matched" pair of AC128's from steve at smallbear some time ago, they were for a FF but I just decided to use them in his "2 knob tone bender" yesterday.
They went into Q2/Q3 as recommended and I had a few "Ge" trannies around, so tried several in Q1.
Settled on a "new" AC128 with a Hfe of about 58-63 ( couldn't get a more accurate reading )  !
SOUNDS KILLER !!
I guess I just got lucky, but the matched pair helped a lot.
BTW he sells a matched set of three now for the "tonebenders"

Marty.

[Eb7+9]

great ! I was thinking of trying Steve's combo out on the 2-knober considering all the positive reviews ...

[inverseroom]

The Build Your Own Clone kit I just built & posted is with matched AC128's and I think it sounds wonderful.  Very much like Gary Louris's Fuzz Face tone on the Jayhawks albums--nicely squared off with some gravelly unpredictability in the hights, and no mud at all.  Interestingly, the instructions for this kit refer to 0.1, but on the board itself it says 0.01, and that's what the cap is, too.  I didn't try switching it and given the great sound, I don't think I'm going to bother...

[MartyMart]

The Build Your Own Clone kit I just built & posted is with matched AC128's and I think it sounds wonderful.  Very much like Gary Louris's Fuzz Face tone on the Jayhawks albums--nicely squared off with some gravelly unpredictability in the hights, and no mud at all.  Interestingly, the instructions for this kit refer to 0.1, but on the board itself it says 0.01, and that's what the cap is, too.  I didn't try switching it and given the great sound, I don't think I'm going to bother...

I just posted a thread about "improving" a Roger Mayer FF ( rocket )
and thats one thing that I found lacking on my rig, I increased the 0.01 output cap to a 0.068 ( 0.1 could be too much ! ) it sounds great now, just a bit more "low mid".
Also put a 2.2n cap on the input jack to ground to roll off some "fizz" which helped to "smooth" things a bit  
If your happy then dont touch it !!

Regards,
Marty.

[RLBJR65]

I've got to agree about the oddball's. I went into a surplus store, bought a couple of eveything that looked like it might be a germ. for 25 cents each. Took them home and got busy testing. I came up with great sounding pair, hardly any hiss, got that great fat mushy Hendrix type fuzz. Also another pair that have a tighter crunchy fuzz. Can't find squat for data on any of them, but who cares! I went back and bought another dozon of each. I have less in all those than the 1 matched pair I bought that hissed and sounded like crap.