low gain AC128

[arielfx]

So basicly I took some of these to test at a friend's and it seems that some of them are pretty low gain and I am wondering if there something I can do to be able to use in them fuzz faces and other effects?

[bwanasonic]

So basically I took some of these to test at a friend's and it seems that some of them are pretty low gain and I am wondering if there something I can do to be able to use in them fuzz faces and other effects?

How low?   :? My problem has been finding low enough ones! Ideally all DIY builders should have a Fuzz Face test bed with sockets and trim pots for testing ( I don't! ). As always the best bet is to use your ears and try them, but maybe you will want a higher gain device for Q2 in a FF. Also try them in any other circuit calling for a PNP Ge ( Q2 in a Green Ringer for ex.)

Kerry M

[stm]

Hi,

Reading RS Components catalog on the Ge trannies section they have the AC128 PNP germanium device listed with an hfe 50-175.

More interesting, they also have the AC127, a NPN device with gain indicated as hfe = 50 norm.  If this is true, this one is pretty low (in theory) and also since it is NPN allows for a negative ground circuit allowing compatibility with the rest of the effects.

Anyway, one would need to buy a bunch of them (perhaps 10 at least) and do some sorting to see if you can get a magic pair (i.e. hfe 70 & 130).  P/N is 294-621.  Gotta check pricing, but I guess its better to buy a prematched pair from Small Bear.

[R.G.]

Unusably low gain germaniums make pretty good germanium clipping diodes if you clip off the emitter lead.