difference between Ge PNP ?

[blanik]

i've seen many Ge PNP used for FFs (faces and factrys) i don't know too much about those...

do they really influence the sound or any Ge PNP will sound the same (in the same circuit?)


R.

[mac]

I have quite a collection of Ge and they sound different. Some sound dark, some sound bright, some have more mids. But if they have the right gain, around 60 - 120, and do not leak more than 200uA, they all sound good. Do not get me wrong, the fuzz is ok for all of them but the freq response is different. It is just a matter of personal taste.


mac

[zjokka]

your bible on this subject is http://www.geofex.com/Article_Folders/fuzzface/fffram.htm
RG article on the subject. Really no general rule to say.

PNP was just more common in the days of germanium. When I built my Ge Fuzz, I only had PNPs so used them. But with NPN GEs you could make a perfect Ge Negative Ground Fuzz, as the second thing to decide is whether to use negative or positive ground. Neg ground would suit your pedalboard best, the interaction with other pedals that is.

I built a GE PNP negative ground, which worked ok, but didn't get much feedback on the project because everybody's convinced that neg ground PNP doesn't work that well. At least Jack Orman believes in it..

But you should also do a search on "piggybacking", there are some great threads on how to use parallel Si trannies to get typical germanium gain

zj

[col]

I have tried a few negative ground pedals using pnp Ge transistors and found them very sensitive to power supply. My -ve ground FF oscillates wildly with anything less than 9v but with a regulated power supply it sounds superb. I got a matched pair from oldradioparts.co.uk and they were worth the extra money! Most of the Ge transistrs I have managed to get hold of are very poor, being full of hiss and low on gain.

Col