Fuzz Face

[Bad Chizzle]

Hello, Solder Junkies

Well, after all these years building things, I finally built a Fuzz Face. I didn't have a 1k or 500k pot, so I had to use 3k and 1m, but it sounds pretty good.I also used Silicon npn transistors. I remember trying to build one back when I was using the wrong end of my soldering iron and failing miserably. I am going to order the correct pots and put them in, in hopes that it will sound even better. Guess I could get to my point sometime in this post! I'd like to add some switchable mods. I've seen a few, but I'm sure there are many. Which mods are the best?

Thanks

[petemoore]

  It's always better to use what you like best.
  the 3k could be trimmed with trim resistors [make the total value smaller, since it is a bias resistor also].
  The 3k could alter the capacitor impedance instead too, put a 1k fixed resistor [or whatever you like] where the gain pot lugs 1/3 were, and use a pot to let the AC bypass be adjustable.
  The mods are:
  Any one of the 12 part values, part substitutions to like...completely different parts, added parts...
  don't know that any can be taken away and it still be a FF.
  I like post-HF-tone control .1uf and <~100k pot to ground.
  And 100k volume pot, 1k or 1k2 '330ohm' resistor [also shown as 470ohm etc., the 'across the top' resistor.
  Reducing the 100k feedback resistor is a good one.
  Obviously biasing using a 'corrected' value for Q2collector resistor.
  Input and output capacitor values...easily revalued in the wire [especially easy if the board value is 'large' and series value is 'added' to make the 2 caps = smaller selected [by ear] value.
  Turn the guitar to like 7, get the FF to clean up...pre-resistor, pre-gain [like volume knob at input, which, btw = volume knob of guitar...another one to preset the max gain at input]. The YAFF's [AMZ] 100ohm Q1emitter resistor is a good/easy to defeat mod, especially if the leads of the 100ohm are made long enough to tack-solder a jumper wire [or alternate value] to.
  Same thing with the 100k feedback resistor, easy to jumper, start with 150k then jumper some value resistor across it, try a pot there etc.
  FF board w/socketed transistors, input/output caps, long legged big resistors [easy to make smaller value with leg above board..just jumper it], big caps on board [so another cap can be seriesed by splice into input wire or output wire]...1k2 for starters then trimmed w/parallel R...all this makes a pretty sturdy [I box and use them after modding/swapping etc.] circuit board, if just for trying trasistors/values then building what you end up with on a different new, more compact board.
 

[Bad Chizzle]

Thanks so much for all that info!

Wow! Cool!

[petemoore]

  I use those methods anyway, but for the 12 part FF build, each part makes a difference, so swapping Q's and diddling with bias is fun/rewarding and necessary if you want to really choose your FF sound, get the rolloff thing happnin' at the Guitar volume knob...or anything else.
  Fun to diddle with but boild down right [knowing the 'temperature'' of the pickups may help ~some] to match your recipe doesn't have even to be all that, basically the 'interactive' fuzzface, IME is all about the not completely fuzzed on tone, somewhere between 5 and 9 [depending...could be a weak output at 10 doesn't get an otherwise 'mild or fierce' fuzzface to be real fierce.
  33k...stays, 100k [47k] 8k2 [trimpot, I prefer 10k trimpot with added 5k6 there...whatever..adjustable between about 5k6 and 15k6 or better].
  I had input cap too thin for a time...
  So yepp, IMO perfect candidate for fiddlin' to set/use type circuit, worth the time if you like FF tones..
  Much of it depends on the type of amplifier though also.
  I have #1 or #2 [really nice FF, that is close to Axis Face at Fuzzcentral, a Ge FF, Tonebender, And and EZ face which is very easy on the ears, easy to use, does the rolloff thing, is temperature stable [reliability of the Si version is a big deal to me].

[Bad Chizzle]

Thanks, Petemoore

I'm having more fun with this build than I thought I would. I can't in truth say that I think I have the best ear for the dead on Fuzz Face sound, but I've been able to get some very Cool settings out of it so far. As is, I believe it's doing the volume roll off thing nicely, although there is a point around 7 that it's a little abrupt. I made the mistake of judging the sound of the thing the other night using the headphone out on my Pathfinder, so at first thought it sounded really bad. But, today when I let the speaker do it's thing it really came alive! Hey, I guess we can all make a rookie mistake once in a while, right?

[Bad Chizzle]

@PeteMoore

So, anyway, I'm going to save this build and put it in a nice box and work up another for messing around with. Thanks for all the great ideas! You can bet that I'll be going through most of them to pimp out the next one!

Still can't believe a haven't built one of these til now!

Thanks again dude, I really appreciate all your time Ann trouble!

[brett]

Hi
one of the key differences between FFs is from the choice of Q1.  Some of the effects are:
low hFE, germanium = xtra bloom, high cut, low gain, vintage dirty fuzz tone
high hFE, germanium = mild bloom, more highs, high gain, very versatile fuzz sound
low hFE Si (e.g. 2N2369A) = bloom, high cut, vintage sound but less fuzzy than Ge
high hFE Si (hFE>100) = minor bloom, more highs, high gain, raucous fuzz tone

Pickups with high output impedance usually benefit from higher hFE.  The classic hFE=70 is fine for many single coils, but was muddy and dull with my high-output, humbucked Les Paul.

IMO it doesn't get any better for Q1 with a strat than a Ge device with hFE=70 to 90 from Japan or Russia (made in the 1970s or 1980s). 
cheers

[Bad Chizzle]

Thanks Brett

I'll look into the GE transistors.

[Bad Chizzle]

Hey, Brett

I'm going to build another Fuzz Face today and I will
Be trying some of the ideas you guys have given me. But, I keep thinking about this (Bloom) you were talking about. Could you elaborate on this for me? It sounds as if it may be the most important part of the sound I'm trying to find from this circuit. I use single coils in my Strat or Tele almost exclusively, so I really need to pretty much tune it to those pickups. Also, would 2n4401 transistors be a good choice for low gain in this circuit?

Thanks!

[brett]

Hi
when you first play a string, the fuzzface "soaks up" volume and treble.  There is some complicated electronics in the fuzzface, and this effect in particular (RG's article "technology of the FuzzFace" at geofex.com is a must-read).  Suffice to say here that low hFE in Q1 is associated with low gain and low input impedance.  The latter causes much of the bloom due to voltage losses in the pickup.  The end result of all this is that many people like a setup where Q1 has a hFE of about 70.  From memory, that gives an input impedance of about 20 k ohms (ie a quarter or less than other pedals), and a solid amount of "sag and bloom".  hFEs of 40 and 140 aren't much good in general.

I have 2N4401s in my current FF.  hFEs of 100 (Q1) and 140 (Q2) (approx).  So it's lowish on bloom.  Things that I like are that they are quite low on leakage, there's plenty of gain, and the mid-high end shows through. 
cheers 

[Bad Chizzle]

Brett,

Cool, thanks again! I'll start measuring my 2n4401's. I'll be searching for the sag and bloom! Although I like the sounds I'm getting so far, I don't think the magic I there yet.

I gotsta find it!