4-Knob Fuzz Face

[pickdropper]

I think I posted a built like this a number of years ago, but this is a bit different so I'll post again.  I slightly tweaked the board so I can use ribbon cable for the footswitch I/O wires.

I used a gold enclosure and backfilled the text.  It's a PITA, but the combination is usually one of the better color looks.

[Leevibe]

I really love that laser etch ink fill technique. It looks superb on this. Guts are perfect right down to the fillets on the 3PDT board. Everything about this looks perfect.

[culturejam]

That's sick.

[jimilee]

Immaculate as always!


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[diablochris6]

Oooh, so nice! Great job, as usual.

[matmosphere]

Dang, those guts, sooooo good.

[jjjimi84]

Just beautiful, nice work

[peAk]

Holy Crap!

So kewl

[TGP39]

So professional.  I thought you burned the bias trim, but quickly realized you're just marking where the bias trim should be set.   You are definitely one of my favorite builders.  Steve. 

[cooder]

Right in yer face....

[JackSkellington]

I'm figuring the schematic, nothing new, I supposed.
The transistors should be the modern germanium, right?
A classic Fuzz Face with a charge pump; a Body control, maybe the Mid control like in the Fulltone 70? Voltage is the Bias, I guess.
I'd like to build something like that, but I didn't think about the charge pump, is it worth?
I wont't find proper hfe of AC128, probably. What about AC126, or AC125 (of this I'd have a larger range of hfe)?

[somnif]

I'm figuring the schematic, nothing new, I supposed.
The transistors should be the modern germanium, right?
A classic Fuzz Face with a charge pump; a Body control, maybe the Mid control like in the Fulltone 70? Voltage is the Bias, I guess.
I'd like to build something like that, but I didn't think about the charge pump, is it worth?
I wont't find proper hfe of AC128, probably. What about AC126, or AC125 (of this I'd have a larger range of hfe)?

The charge pump is there as an inverter. The Fuzz Face was from an era where transistor technology meant it was easier to design with a Positive Ground in mind. Makes using one with a modern power supply a pain in the ass, so adding little extra circuitry to get around the headache is worth the "mojo" cost.

[pickdropper]

I'm figuring the schematic, nothing new, I supposed.
The transistors should be the modern germanium, right?
A classic Fuzz Face with a charge pump; a Body control, maybe the Mid control like in the Fulltone 70? Voltage is the Bias, I guess.
I'd like to build something like that, but I didn't think about the charge pump, is it worth?
I wont't find proper hfe of AC128, probably. What about AC126, or AC125 (of this I'd have a larger range of hfe)?

The charge pump is there as an inverter. The Fuzz Face was from an era where transistor technology meant it was easier to design with a Positive Ground in mind. Makes using one with a modern power supply a pain in the ass, so adding little extra circuitry to get around the headache is worth the "mojo" cost.

Yep, exactly this.

And the voltage control is a voltage reduction not a bias control.  It allows you to run the circuit at a lower voltgae, as if the battery is sagging.

[JackSkellington]

I'm figuring the schematic, nothing new, I supposed.
The transistors should be the modern germanium, right?
A classic Fuzz Face with a charge pump; a Body control, maybe the Mid control like in the Fulltone 70? Voltage is the Bias, I guess.
I'd like to build something like that, but I didn't think about the charge pump, is it worth?
I wont't find proper hfe of AC128, probably. What about AC126, or AC125 (of this I'd have a larger range of hfe)?

The charge pump is there as an inverter. The Fuzz Face was from an era where transistor technology meant it was easier to design with a Positive Ground in mind. Makes using one with a modern power supply a pain in the ass, so adding little extra circuitry to get around the headache is worth the "mojo" cost.

Ok! So it can works at 9v with a standard PSU, but it has positive ground, if I understand. Cool!

And the voltage control is a voltage reduction not a bias control.  It allows you to run the circuit at a lower voltgae, as if the battery is sagging.

Yes, it was that I meant, I just told wrongly! Bias and Voltage controls are two different kind of mod.

Thanks!

[somnif]

Ok! So it can works at 9v with a standard PSU, but it has positive ground, if I understand. Cool!

With the charge pump inverter, the thing has a normal negative ground (so you can use a normal power supply, daisy-chain it with other effects, all that fun stuff). The power portion of the circuit just "wraps around" the classic FF circuit. So the FF "sees" -9V, but you power it with a normal +9V power adapter.