fuzz face/white noise?

[Booga]

Hi, first time here, and I have a question if anyone would be so kind.

I've finished my BC108 fuzz face to original specs except for using 10K trim.  It works OK-ish.  With the 1K LIN pot set between 3/4 - 4/5 to full I get serious white noise and oscilation, maybe it's just oscilation depending on your description.  Anyone have any thoughts as to why?

I'm also having to max the 10k pot to get Q2 base and emitter voltage close, below that, it's the usual farty / gatey story.

Many Thanks.

[Booga]

Ah.... Done some more research.  47 or 100 pF cap betwen the two collectors correct?  Thanks to runoffgroove's site.

[Sir H C]

oscillation is often poor wiring or soldering.  If things are too close together these high gain circuits can oscillate.  The cap (really from the base to collector of one device) will kill some oscillations but will also cut the brightness of the pedal.  Okay, so you get .7V over the 1k resistor (or should be somewhere around there) so now the collector should have 7V if it is 10k.  If not, your pots might be off in value.

[Booga]

Thanks for that, I'll check it out.  It's built on perfboard with my own component layout, which may not be the best.

Thanks.