Face Full of Fuzz...

[Coda]

Built this one yesterday: its a Fuzz Face PCB from Tayda. First, a story: a month or so ago, a friend of mine came over with his Hartman BC108 Silicon Fuzz. He bought it about a dozen years ago, and was never too impressed. I was entering my seasonal Fuzz Face phase, and wanted to shoot the Hartman out with my BC109 Sunface (they were nearly identical). The next day I was itchin' for a BC108 Fuzz Face...well, a new one. My first ever build was the Twin Face. I concentrated on the Ge side mainly, and the Si side never really sounded that good (I knew nothing of Hfe, Ge were bought measured from Pedalhacker).

I breadboarded this a week ago. It was...interesting. I started with the schematic Tayda provides with the PCB. It was definitely a schematic. Firstly, the only schematic provided is for PNP. All it says for Si is to swap the electrolytics. It also had a 470R in at R3, and a 50k trimmer for the bias. This was hilarious: the only useable tone was to the extreme of the trimpot, and it was cleaner than it should be. I ended up with a 680R at R3, and a 10k trimmer for the bias. Much better. Once it was assembled (Tayda pre-drill) I wired it up, and added a 47p cap from Q1's collector to base (cures oscillation). Paint is from a can; hammered bronze. It turned out pretty good...

It sounds like a BC108 Fuzz Face: a bit fizzy, a bit raw, both thin and thick at the same time. Cleans up pretty well (as well as it needs to, anyway). The only issue, which I knew going in, is that this pedal does NOT like being on my board. By itself its excellent. On the board its dark, muddy, and doesn't really clean up at all. Oh well...

I think I'm gonna add a battery snap...

 

[steviejr92]

DUUUDE this is awesome! Great build man!

 

[Big Monk]

Looks great!

Little tidbit for the future: feedback bypass cap is usually better (i.e. you can use a smaller cap) at killing oscillation. Somewhere between 47-150pF should work.

The smaller cap means you get less attenuation in the high frequencies.

 

[Coda]

Looks great!

Little tidbit for the future: feedback bypass cap is usually better (i.e. you can use a smaller cap) at killing oscillation. Somewhere between 47-150pF should work.

The smaller cap means you get less attenuation in the high frequencies.

I meant 47p...

 

[Harry Klippton]

I like that enclosure finish. What is it

 

[Synchrony Pedalworks]

Great build!

 

[Big Monk]

@Coda

What did you use for gains on the transistors?

 

[benny_profane]

@Coda

What did you use for gains on the transistors?

42

Nice one, @Coda. Glad you finally made a fuzz face!

 

[Coda]

I like that enclosure finish. What is it

Rustoleum Hammered Bronze. I’ve had mixed success. It always works, but sometimes the effect is different. Sometimes it never really ‘fires’ off, or barely does, resulting is small ‘hammer marks’. This time it went especially well…

 

[Coda]

@Coda

What did you use for gains on the transistors?

I don’t recall 100%, but I think it’s something like 200/400…maybe 210 and 420. It wasn’t the lowest gain 108 for Q1, but it was the highest for Q2…

 

[Harry Klippton]

Rustoleum Hammered Bronze. I’ve had mixed success. It always works, but sometimes the effect is different. Sometimes it never really ‘fires’ off, or barely does, resulting is small ‘hammer marks’. This time it went especially well…

I've used it too. How light or heavy you spray it matters, and I think temp and humidity seem to have an effect on how it comes out too

 

[MichaelW]

I've used it too. How light or heavy you spray it matters, and I think temp and humidity seem to have an effect on how it comes out too

I’ve had mixed results with this too. Did you use the “mail box paint” type? Or regular hammered bronze? I’ve found the reeeeeaaaaly thin coats, about 3 over a base of primer helps a lot. It takes forever to dry for me.

 

[Big Monk]

I don’t recall 100%, but I think it’s something like 200/400…maybe 210 and 420. It wasn’t the lowest gain 108 for Q1, but it was the highest for Q2…

I've been thinking lately that staggered gains seems to make it "fuzzier", i.e. more square wave distortion, even at dirtier amp settings, but the cleanup suffers.

It's amazing to me how much mileage you can get out of this circuit.

 

[steviejr92]

I've been thinking lately that staggered gains seems to make it "fuzzier", i.e. more square wave distortion, even at dirtier amp settings, but the cleanup suffers.

It's amazing to me how much mileage you can get out of this circuit.

When you say the cleanup suffers how bad is it? Almost no cleanup at all?

 

[Big Monk]

When you say the cleanup suffers how bad is it? Almost no cleanup at all?

No, no. Not that bad.

Matched gains around 285 hFE, plus some strategic gain reductions seems to give almost Germanium type cleanup around 6 on the guitar volume. Not the same feel of course because Germanium seems to have a different feel under the fingers but the quality of the cleanup is close.

With staggered gains, i.e. Q2 reasonably higher than Q1, in silicon Fuzz Faces things seem to get fuzzier, more zingy and doesn't clean up as fully.

 

[Coda]

I've been thinking lately that staggered gains seems to make it "fuzzier", i.e. more square wave distortion, even at dirtier amp settings, but the cleanup suffers.

It's amazing to me how much mileage you can get out of this circuit.

I agree.

When you say the cleanup suffers how bad is it? Almost no cleanup at all?

Full fuzz at full volume, medium distortion at 8, various levels of OD anywhere beyond that...

 

[steviejr92]

This is good to know. I plan on making a fuzz face on vero now that i have a few Ge transistors laying around.

 

[Coda]

With staggered gains, i.e. Q2 reasonably higher than Q1, in silicon Fuzz Faces things seem to get fuzzier, more zingy and doesn't clean up as fully.

As it should be...into a clean amp...

 

[Harry Klippton]

I’ve had mixed results with this too. Did you use the “mail box paint” type? Or regular hammered bronze? I’ve found the reeeeeaaaaly thin coats, about 3 over a base of primer helps a lot. It takes forever to dry for me.

this is the one I use

 

[MichaelW]

this is the one I useView attachment 34154

Yah, that's what I used except the copper colored.