Fuzz Face Mod

[Discobungle]

So, in your opinion, what would adding a B2K pot between R2 (33k) and R3 (470R) do in a fuzz face?

 

[Cybercow]

Schematic? (Too many FF schematics from which to choose to simply guess which one.)

 

[CR0SSBL4DE]

Mess with the transistors bias.
What are you trying to achieve with that mod?

 

[Discobungle]

Got the idea from an Aion kit. Here's the schematic. Looks like it's to mess with the mids a bit.

 

[CR0SSBL4DE]

Got the idea from an Aion kit. Here's the schematic. Looks like it's to mess with the mids a bit.

There's no pot between the 33k resistor and the 470 resistor there. Could you draw an schematic?

 

[Discobungle]

Sorry. Here's the schematic I drew and breadboarded. This is what I was thinking.

 

[Giorfida]

Sorry. Here's the schematic I drew and breadboarded. This is what I was thinking.

Never seen it done, but a fuzz face is such a simple circuit, wouldn’t take long to breadboard it and try it!

 

[Discobungle]

I tried it and actually loved the sound. I'm just trying to figure out exactly what that pot is affecting. Is it Q1, Q2?

 

[CR0SSBL4DE]

Sorry. Here's the schematic I drew and breadboarded. This is what I was thinking.

Oh, it's in series with the 470R. (Also, it's a NPN fuzz face)

It's changing a bit of the Q2 bias and common emitter gain, but mostily the output amplitude is increased since the 8k2+470R voltage divider (original circuit values) is been modified. I read the Aion documentation and I dont see how it could affect mids.

 

[Discobungle]

Not sure. He just described it as affecting the mids. Thanks for the detailed description though.

 

[Robert]

Thorpy calls it a "Smooth" pot in the Tacit Blue.

It behaves almost like a presence control.

 

[CR0SSBL4DE]

Thorpy calls it a "Smooth" pot in the Tacit Blue.

It behaves almost like a presence control.

The smooth pot it's at the input. The pot we are referring here it's actually the bias pot.

 

[cdwillis]

The Fulltone 69 has a 1k pot in series with a 220 ohm resistor set up similar to that Tactical Fuzz, but he labeled it Contour. It's going to affect q2 bias, but I'm not sure if he biased Q2 with the pot cranked or at what position.

 

[Robert]

The smooth pot it's at the input. The pot we are referring here it's actually the bias pot.

View attachment 67870

Ahh yeah that's right. Wrong pot.

 

[manfesto]

The Fulltone 69 has a 1k pot in series with a 220 ohm resistor set up similar to that Tactical Fuzz, but he labeled it Contour. It's going to affect q2 bias, but I'm not sure if he biased Q2 with the pot cranked or at what position.

Aion's instructions for their Solaris board say "Set the Contour knob just above 9:00" when biasing, I vaguely remember an earlier version of the board specifically saying they'd borrowed the "Contour" control straight from the Fulltone 69 so I'm assuming just above 9:00 was the case in the original

 

[CR0SSBL4DE]

The Fulltone 69 has a 1k pot in series with a 220 ohm resistor set up similar to that Tactical Fuzz, but he labeled it Contour. It's going to affect q2 bias, but I'm not sure if he biased Q2 with the pot cranked or at what position.

From fulltone website:
A Contour Knob lets you dial in Midrange, Harmonics and Sustain
Seems like the Aion FX Epsilon Silicon Fuzz is pretty close to the Fulltone 69, but adding the Jack Orman pickup simulator at the beginning.

 

[HamishR]

What I want to know is what the transformer is doing in the Thorpy pedal. How can running the signal through the primary of a small transformer change the sound? At most it would be simulating a resistor. Am I missing something?

 

[JamieJ]

@HamishR I think Thorpy is using the transformer as a pick up simulator to allow you to have this pedal not be first in the chain.

 

[HamishR]

Thanks for the response! Hmmm... I wonder how well it might work at that?

 

[Cybercow]

@HamishR I think Thorpy is using the transformer as a pick up simulator to allow you to have this pedal not be first in the chain.

Precisely! That transformer at the input emulates a guitar pickup and changes the input load/impedance.