BC108 Sunface oscillates when gain is maxed out

[GrooveChampion]

I built the entire thing to spec as said in the layout. Everything words right, but the damn thing oscillates and makes this annoying high pitched squeel when the fuzz is maxed out.

Is there a way to solve this? I tried replacing both transistors and absolutely nothing.

[Neil mcNasty]

This has happened to all my fuzz face style builds (and the One Knob fuzz variants), using BC108/109...
The fact that the emitters are connected directly to ground sets it to maximum gain, this is obviously to much...
By adding a 100 Ohm (or a bit more) between emitter an ground (for Q1) or between the Fuzz pot's lug 1 and it's ground connection (Q2), you will prevent it from going to max gain and into oscillation.

Here's a second thought: Have you tried it with batteries or a different power-supply?
The reason I ask is that when using poorly filtered power-supplies, you sometimes can get oscillation with very high gain circuits.
This issue includes many of the "professional" power-supplies as well, like the horrible T-Rex units, and not just the cheap one-spot units.
Many of them only has just one regulator for all the 9V outputs and no decoupling/separation between the outputs, making it function just like a one-spot with a daisy chain.
This is why I mainly buy one-spots and build myself a one-input with multiple output power-filtering box, with a "Huminator" decoupling circuit for each outlet.
Here is a couple of forum links with information and layout regarding the Huminator:
http://guitar-fx-layouts.42897.x6.nabble.com/Bypass-bleeding-td33074.html;cid=1486678163399-94#a33084
http://guitar-fx-layouts.42897.x6.nabble.com/Weird-quot-hum-quot-from-a-couple-of-pedals-td20501.html;cid=1486678163399-94#a20504

[GrooveChampion]

Well, I will try the resistor idea out, see what happens.

Actually I didnt, I will give it a try.