I've never owned a Fuzz Face.

[1878]

Hello Everyone...

As the title says, I've never owned a Fuzz Face, which I find a bit weird considering the amount of pedals I've used, tried and owned over the years. I think it's time I remedied this, so I'm gonna build myself one or maybe two. My questions are:

What types of transistors (Germanium and Silicon) do people recommend ?? As of now, I've got a couple of AC128's with a hfe of approx 100 and a load of untested BC108's. I've also got a few OC44's knocking about somewhere.

Is there any value in replacing the 8.2k resistor with a trimpot ?? I've read some people who say it really helps with the biasing, and some who say it does almost nothing ?!?!

Lastly, is there any way of switching between Germanium & Silicon transistors in one unit.

Thanks in advance.

[CynicalMan]

A couple of things for you to read:
www.beavisaudio.com/Projects/FuzzLab/FuzzCloneMods_V2.gif
www.geofex.com/Article_Folders/fuzzface/fffram.htm

IMO the biasing mod is sometimes worth it, but it depends on the transistors. If their bias is way off, the fuzz will sound gated. None of the vintage mojo-riffic fuzzes did it, but it's probably worth doing just in case.

[Solidhex]

The circuit is so simple you might as well breadboard it to see if you like silicon or germanium better.

--Brad

[1878]

Thanks for the replies...

I'd read the Geofex article and I can't believe I missed the Beavis one !?!? It was just what I was after.

Anyone got any thoughts/experiences with different types of transistors ?? I always socket transistors as a rule, but I suppose what I'm after is a sort of 'best of both worlds' deal. I'd decided on either one unit with switchable transistors, or two separate units.

One of the reasons I've never owned a Fuzz Face is because most of ones I've tried have been crap !! It's only since I've been building effects and seen what other people have done that I've thought, 'Aaah... That's what it's supposed to sound like !!'. It's still THAT sound, but better.

[brett]

Hi
there is general consensus, and good theoretical reasons why a good Ge transistor is the best device for Q1 in a fuzzface.  The clipping will be more asymetric.
However, FINDING a good Ge transistor isn't as easy as finding a good Si transistor.  Although many people advocate AC and NKT devices, the reasons are largely nostalgic IMO.  Japanese (2SB) and Russian (GT) devices have much lower leakage, lower noise and tighter hFE ranges.  The Russians were still making Ge devices in the mid 1980s and had sorted out the technology to a great degree.  GT308s are fairly easy to find, and have lovely low hFE (maybe too low for some people) and almost no leakage.  The minimal leakage means you can get a realistic hFE measurement for many Japanese and Russian devices in a DMM (with hFE indicator).
cheers 

[tcobretti]

Easy - just build Fuzz Central's Axis Face.  Just amazing.  My 'Go To' Fuzz Face, and I have a few including Ge.

[amptramp]

The problem with a fuzz face is that if you have low-gain transistors (which many people prefer), you have little DC feedback to stabilize the bias point.  If you are using one in a studio, this may not be a problem.  If you go out on gigs, you may find that temperature effects change the current gain and bias to the extent that the unit sounds different depending on whether you just came in from tundra cold or desert heat.  You can add bias controls to help accommodate this, but there are fuzz type effects based on diode clipping that will have more predictable and repeatable response.

Germanium as built in the US in the 1950's and 1960's had about 1000 times the leakage current of silicon and this current doubles with each 10 degree C rise in temperature.  If the later Japanese and Russian transistors are sufficiently stable they may be usable but you can passivate silicon with its oxide (which is basically non-conductive quartz) but if you oxidize germanium, the oxide is conductive, so no one passivates germanium that way.

[ckyvick]

Build the one knob fuzz with high hfe(I like 500+) silicon transistors, just try out standard npns in sockets until you find a set you like. my favorite fuzz face variation.
or build a tonebender with a matched set of germaniums from smallbear

[petemoore]

  The board is inexpensive, and sockets can be used to make a still inexpensive FF Test-Perf build.
  The 8k2 is a good 'center #', but when you this and then that or the other transistors, to bias the amplifier you'll need to adjust the Q2collector bias. I start with 4k7 or so and add a 10k trimpot [for 14k7 - 4k7 adjustment spread evenly across the pot], 20k does as well but is a bit touchier to adjust.
  Then make the 100k start as 150k feedback resistor, long legs boosting the body 1/4'' above the board makes it really easy to clip on a pot to find what different values do there [when-and-if] or / and then piggybacking a permanent resistor to achieve preferred value.
  Input cap, output cap, and even the 22uf bypass cap can all be socketted, then to reverse NpN for PnP [reversing polarity on...everything for sure] can be done with a red for black leadswap on the battery, a flip of the 22uf [and everything that is polarized component being polarized by the PS needs 'flipped around.
  There's your board that can have pretty much any FF type, all transistors etc. for testing out your FF sounds.
  I have one of these, 2 of the other. I find having them in bypassable, shielded boxes fascilitates the advanced testing the circuit needs. Having 2 such boxes allowed tweeking this one, re-tweeking that one, then seeing which [for instance input cap choosing, gain setting etc.] has the greatest versatility and also grinds out heavy fuzz.
  Remember that the FF can put the volume knob on the guitar pickup into gain-knob-mode, use the rolloff feature to reduce gain/clean up the sound. Transistors that are over the top with gain/fuzz won't feature the same clean-up-ability, try lower Hfe in Q1.
  Read the GEO article on technology of the FF.

[1878]

I'm thinking I'll just build a Fuzz Face but socket all the important components. It's not a priority build so I'll take my time.

I own a 70's Supa Tonebender which I was given in the early 90's. Everyone else wanted to sound like someone with huge hair at the time, but I loved it. I'll do myself a copy one of these days 'cos the original doesn't leave the house.

[solderman]

I made s shoot out between the two a while ago
for what it's worth

http://www.diystompboxes.com/smfforum/index.php?topic=76047.msg620484#msg620484