Piggyback Ge's

[petemoore]

Just kinda wondering why I haven't seen reads about people using Ge's of various gains with piggyback gain reducers on them.
 Anyone try marrying the Ge's to Miss Piggy?
 Would the non-active transistors have to also be GE? [For some reason Si's PNP's as 'dummy' Q's would change the tone compared to ge?]

[brett]

Hi Pete
for every Ge tranny that I have with hFE around 130 I have two with hFE around 70.  So I'd rather have a mod to INCREASE the hFE of Ge trannies.  

Of course, as you know, with Si the curse is too high hFE, so the piggyback thing is quite handy for Si.

cheers

[Paul Perry (Frostwave)]

I'd rather have a mod to INCREASE the hFE of Ge trannies.

Maybe a darlington combination, with a Si followed by a Ge? The Ge character should remain for the critical soft output saturation.

A good story about the first Darlington here:
andros.eecs.berkeley.edu/~hodges/DarlingtonCircuit.pdf

What they DON'T say (and probably don't know!) is that the Darlington combo was discovered earlier, by A.R.Perlman (of ARP synth fame) who didn't patent it at all, because he (not being a lawyer) thought it was "obvious".

[brett]

Cool idea Perry

Also, your idea made me realise that a simple stage with adjustable gain (say 1.1 to 3) might make a lot more Ge transistors acceptable as Q2 in a fuzzface.  (it would fool with the input impedance of Q1, so I don't think you could use it there)

Hmm.... must test this out.  Simple BJT with floating base and 100k collector resistor and 22k resistor + 50k trimpot on the emitter... Hmmm...

[Paul Perry (Frostwave)]

go fer it Brett! sometimes you just have to "suck it and see"!

[WGTP]

Some of the Tone Bender circuits use a darlington in the first stage.  Check Fuzz Central.