This Week on the Breadboard: The Spirit in the Sky Fuzz

[Chuck D. Bones]

Mode 4 allows Q2 to be biased at or near saturation. The FUZZ pot not only varies the gain. it also varies the bias.

 

[Chuck D. Bones]

Here's an alternate BIAS circuit:


Q1 HFE ~ 100
Q2 HFE ~ 140

 

[Cybercow]

So place the 22k between the collector and BIAS-1, or betwixt BIAS-3 and the gate?
Based on the discussion thus far, I imagine it should be the former (green below) not the latter (blue below):

View attachment 119560

Hm I think I thinkered it out, should be the green.

Green is certainly the easiest. Blue entails cutting a trace cuz lugs #2 & #3 are joined on the PCB.

 

[genXslacker]

Here's an alternate BIAS circuit:

View attachment 120748
Q1 HFE ~ 100
Q2 HFE ~ 140

I'm away from home for a few more days, but that's going on a breadboard as soon as I get one in arm's length.

 

[Chuck D. Bones]

One more mod. It lets us set the SUSTAIN lower if we want. Maybe nobody does. Max sustain is the same. I also reduced C1.

 

[genXslacker]

It lets us set the SUSTAIN lower if we want. Maybe nobody does. Max sustain is the same.

To me, more choice is always better on a pot, so long as it's functional. The only thing I don't like is when a pot lets me paralyze an LFO or something like that... not an issue here, obviously.

I'm really eager to get these on a breadboard. I'm in the cult that is obsessed by the tone on the record.

 

[Feral Feline]

Green is certainly the easiest. Blue entails cutting a trace cuz lugs #2 & #3 are joined on the PCB.

View attachment 120760

Agreed GREEN is the way to go, as stated in my post, but if blue — NO NEED TO CUT A TRACE!

Should I have gone for blue I'd simply use a solder-lug pot (or simply not solder legs 2&3 to the board — tie lugs/legs 2&3 together on the pot and run the resistor to the Q2-side of C4. Lug 1 as it is, of course.


Nonetheless, I think we're green, Super, even...