Fuzz Face Tone Differences and modding?

Beexter

I've got 2 silicon fuzz face style pedals, both with BC108's  - one sounds thick and wooly and the other is quite a bit brighter.

Is it just the difference in transistors that affects the brightness of the tone or is there something else in a fuzz face circuit that affects this?

Also, I wouldn't mind messing around with different transistors, and particularly want to try BC109's and BC183's - anyone know where I can get hold of these in the UK? I've read up on the Geofex "Technology of the Fuzz Face" article and there are a number of suggested gain ranges to try but I'm struggling to find anywhere that stocks gain matched transistors.

stickyfiddle

I have a germanium kit-build from pedalparts. I put some random old transistors in (can't remember what though. K108-N or something?!?!). It's the only fuzz face I've ever really enjoyed using. Mine came from smallbear iirc.

I'm far from a fuzz expert but my experience is that the transistors affect the character of the fuzz more than the brightness, and it's the output caps and value of the volume pot that impact bass and treble response more than any other components

I;m sure someone far more knowledgeable will be along shortly to explain!

juansolo

The Fuzz Face is one of the simplest circuits out there. However people often think because the design is simple it's an easy build. It just isn't. There are so many variables in making a decent sounding FF. Very, very few people even make an attempt at biasing them properly for a start. Then there's accepted wisdom on parts/values vs what works... Then, certainly when it comes to Ge transistors, there's sourcing good transistors... Which is nigh on impossible these days. Add to this that essentially your guitar is part of the circuit (hence they have all sorts of bother with other effects/where they are in the signal chain, etc) you're just in a world of pain.

Now you can make Si fuzz faces 'till the cows come home. Indeed the number of fuzzes out there that underneath are a Si fuzz face is hooooooge. Still I'd go with an alternative. These effects, like MkII tonebenders and the like, are just too much of a PITA to deal with. Yet guitarists hang on to these things because so-and-so used one back in the day. Let me tell you, if so-and-so was around today, he wouldn't be using a fuzz face... Too much of a ball ache.

pintspiller

yeah, it would be interesting to see what those fuzz users would be using if they had the same selection of gear as we have today.

Beexter

What would be your alternative @juansolo? I think I'm definitely more of a fuzz-face fan than a Big Muff. The 2 I keep coming back to are an MXR Classic 108 and your Lunar Module clone. For a straight up fuzz-face - the MXR I have now has seen off quite a few contenders (although I haven't tried an analogman sunface). It's just.......... right

ThorpyFX

Beexter said:

What would be your alternative @juansolo? I think I'm definitely more of a fuzz-face fan than a Big Muff. The 2 I keep coming back to are an MXR Classic 108 and your Lunar Module clone. For a straight up fuzz-face - the MXR I have now has seen off quite a few contenders (although I haven't tried an analogman sunface). It's just.......... right

lunar module clone all day every day.... trust me, its wicked and @juansolo builds a mean pedal.

Beexter

ThorpyFX;1061792" said:

lunar module clone all day every day.... trust me, its wicked and @juansolo builds a mean pedal.

Yep, I've got the Mxr and Juansolo's Lunar Clone (and a Skreddy original!) and I haven't come across anything I prefer more than these 2......yet.

juansolo

Yep, lunar module is a good 'un.

Magnetic_Effects

Beexter said:

I've got 2 silicon fuzz face style pedals, both with BC108's  - one sounds thick and wooly and the other is quite a bit brighter.

Is it just the difference in transistors that affects the brightness of the tone or is there something else in a fuzz face circuit that affects this?

Also, I wouldn't mind messing around with different transistors, and particularly want to try BC109's and BC183's - anyone know where I can get hold of these in the UK? I've read up on the Geofex "Technology of the Fuzz Face" article and there are a number of suggested gain ranges to try but I'm struggling to find anywhere that stocks gain matched transistors.

Are both pedals biased at the same voltage? Different bias points will affect the tone and feel of the fuzz.

Bitsbox stock BC109's and BC183's.

Bitsbox

Beexter

Thanks for the reply @Magnetic_Effects and for the link! Not sure on the bias voltages. the brighter one has an external bias pot but the thicker sounding one is just volume and fuzz and sounds just right as is. I guess there is an internal trimmer but I have no intention of messing with it.

ThePrettyDamned

I made an axis fuzz, which is a silicon fuzz face variant but it's supposed to be somewhat more consistent. I loved mine, but needed to be first in the chain so still a fussy bugger.

I love my ultrastoner, jumbo tonebender and zoom ultra fuzz pedals, though it's fair to say none clean up like the axis fuzz, which will do a wonderful crystal clean.

Magnetic_Effects

@ThePrettyDammed Was it the Fuzz Central Axis Fuzz or the Roger Mayer Axis Fuzz?

babysnake

I have a @ThorpyFX Eagle (Lunar module clone) and a Monsterpiece NPN (Fuzz face clone). Both amazing with my Vox. 

They also stack really well together with my @juansolo Klone. I never thought I would be able to get Marshall style grind from the Vox but these three pedals combined take me close enough!

Roland

The BC108 is a very primitive transistor. There is not a great deal of consistency between individuals. Also they can migrate, and change values, which can have an affect on tone as well as distortion level. Over heating during soldering, or using too high a voltage, can cause this. In fact I've seen a BC108 that was corrected the wrong way around and still worked. 

The resistors and capacitors in the two pedals can also have different values. Tolerances can be +20% on standard components, and even more if they've been heated or aged.

So put all three into the mix and it's not surprising that the pedals sound different.

Beexter

Thanks for the response's everyone. @Roland, my understanding is that the Fuzz-face is a very simple circuit but getting the right component values is the key between good and bad sounding pedals.
Let's say we're sticking with silicon variants, which component in the circuit would you say has the biggest effect on tone?

Roland

Capacitors and resistors. Difficult to say which one(s). Usually you can't measure them without I soldering them, and the heat of doing so could change the value. I used to make these when I was at school. If 'twere me I'd buy a handful of components and some Veroboard, solder up a couple of new circuits, and see which one I liked best.

ThePrettyDamned

Magnetic_Effects;1064443" said:

@ThePrettyDammed Was it the Fuzz Central Axis Fuzz or the Roger Mayer Axis Fuzz?

It's a Roger mayer alike from poodle pedals.

Great thing, though I broke the pcb when I smashed a pot. Oops.

I'd have another though. Even with pickups hot enough to cause squish in the tone, just max volume, max gain, take a hair off each until it's not squealing and voila, clean as you like, crunchy as you like, filthy as you like.