Twin Face PNP Biasing

[JetFixxxer]

I went to check the biasing of my Twin Face with the trim pot fully CCW I can only get it to -5.35v. Bad trim pot?

 

[ferdinandstrat]

I went to check the biasing of my Twin Face with the trim pot fully CCW I can only get it to -5.35v. Bad trim pot?

Actually there's another option: You are most likely using PNP Germaniums right? Well they are incredibly sensitive to heat. It happened to me too, I built a PNP Germ Fuzz Face and suddenly it sounded splatty and....crap, checked the voltages, pot vaules, tried a 500K bias pot and nothing....turns out I had to throw the thing in the fridge cos it was middle of the summer

 

[music6000]

Did you change the toggle mode switch to the PNP side to adjust Bias.
Toggle switch feeds voltage seperately to each side!

 

[JetFixxxer]

Did you change the toggle mode switch to the PNP side to adjust Bias.
Toggle switch feeds voltage seperately to each side!

Yes I did.

 

[Many__Of__Horror]

Yes I did.

Did you end up figuring this out, I just built one and am finding the exact same thing. Though I seem to be getting no sound out of the PNP side so i have some more investigating to do.

EDIT: I had the PNP trannie in the wrong way with the base & collector swapped. Put them in the right way & the voltage is now correct & I get fuzz.

 

[JetFixxxer]

Nope.

 

[benny_profane]

What was the source of your transistors? Were they measured for gain/leakage?

 

[JetFixxxer]

What was the source of your transistors? Were they measured for gain/leakage?

I got them ebay about 8 years ago and they were in my original Fuzz Face Clone. I don't remember leakage measurements.