Fuzz with variable voltage

[Big Monk]

Omit R5 from the Executive Fuzz PCB.
Connect a wire from the top pad of R5 to lug 3 of your new Starve pot.
Connect a 10K resistor from lug 2 of the Starve pot to the lower pad of R5 on the PCB.

It just dawned on me that this is exactly what we're describing right here, so take a look at this schematic:

Ermahgerd! Fuzz - PedalPCB.com

Compare to J.Rockett WTF

www.pedalpcb.com

The Ermahgerd uses a 1K resistor and 100K pot.

Here's a bigger / higher res version of the pic above.

Glad to see they are branching out from the Electra…

Wait a minute…

(says the guy building Fuzz Faces…)

 

[Robert]

Do any PPCB fuzzes have voltage control ala mythos hephaestus.

To answer your question directly, this is almost exactly that, except it also includes a Volume and Gain pot, and an EQ switch.

Ermahgerd! Fuzz - PedalPCB.com

Compare to J.Rockett WTF

www.pedalpcb.com

If you really want a 1-Knobber jump the gain and volume pots and omit the EQ switch.

 

[Big Monk]

To answer your question directly, this is almost exactly that, except it also includes a Volume and Gain pot, and an EQ switch.

Ermahgerd! Fuzz - PedalPCB.com

Compare to J.Rockett WTF

www.pedalpcb.com

If you really want a 1-Knobber jump the gain and volume pots and omit the EQ switch.

So is the Mythos a clone of a clone?

 

[Robert]

So is the Mythos a clone of a clone?

It doesn't have the EQ switch and the Starve values are different so it's probably just a clone, not a clone of a clone.


This is also the basis for some (most?) of the Trombetta fuzzes as well. If I'm not mistaken Paul Trombetta designed the WTF for Rockett.

 

[Ginsly]

Omit R5 from the Executive Fuzz PCB.
Connect a wire from the top pad of R5 to lug 3 of your new Starve pot.
Connect a 10K resistor from lug 2 of the Starve pot to the lower pad of R5 on the PCB.

Ah! Ok, this is very interesting. In the original thread they mentioned using a 1k resistor to connect the lower pad of R5 to lug 2 of the new pot (B50K was mentioned by a very helpful @PedalBuilder ), then connecting lug 3 directly to the emitter leg of Q2, and connecting (the unused) lug 1 to lug 2. Nothing connects to the top of R5.

Beginner’s question: are both methods achieving the same thing?

Do I still connect lugs 1 and 2 in your method?

Funny enough, I was THIS close to getting an Ermahgerd! In my last PedalPCB order. Doh! Guess I’ll have to mangle this Executive instead!

Also - @Robert you mentioned that the Starve values are different between the WTF and the Hephaestus - how can you tell? The pic doesn't show the pot value for the Mythos. Curious, as I'm gonna try this mod on the Executive very soon - thanks!!

 

[Ginsly]

Voltage Sag/Bias control is super overrated in my opinion. Everything is happening at the extremes so a bias switch is a better option.

Can I ask you to explain how I would set up a transistor bias knob on the Executive? I added an overall voltage starve following Robert's very helpful instructions, and it actually sounds excellent.

I think I'd ALSO like to be able to adjust the transistor bias, as it might help me dial out some of the circuit hiss. I think having both of those controls could be interesting, too. Thanks @Big Monk!