Keeley Red Dirt Germanium Overdrive?

[RRJackson]

This is a Tube Screamer-style circuit, isn't it? Is he using a germanium transistor as a diode? Anyone know what the deal is with these?

-Rob

[Kipper4]

Just had a quick look at the promos and if like you say its a TS with germ transistors in the feedback loop then this is nothing new around here.
Typically low gain germ transistors are used because they are not good enough for a fuzz face and its a shame to waste them.
I have lots of low gain germs i bought dirt cheap that i may use for the same purpose some time.
Heck you could probably build something similar using tonepads TS and mod it to use germanium transistors instead of diodes in the feedback loop easily.
Put a switchable input cap on the input and your usual TS tonestack and booooom you'd be pretty close to the red dirt.
Do a search for clipping amps and configurations. you will find some intresting combinations.
assymetric, symetric, series zener diodes, body diodes the list is long.

[RRJackson]

You've gotta forgive me, 'cause I'm a little (lot) thick-skulled, but normally that's using the transistor as a diode, right? I mean, with a MOSFET you're just connecting the Gate and Drain if I've been looking at these things right. So with a transistor you'd do what, connect the Base and Collector? Would that work with, "dead" transistors where only two legs test as active and the analyzer identifies them as diodes?

FWIW, I just started an Aion Tube Screamer build that has a pair of switchable clipping sections. I just wired the first one up for asymmetric clipping using four germanium 1N34A diodes on one side and two on the other. I was planning to use MOSFETs and 1N34As in the other clipping section like a Zendrive pedal, but if I can make use of some of my low-gain transistors that would be really cool instead.

-Rob

[Kipper4]

Sure, for example then just look at the schematic diagram for your transistor and you will see where the diode is and which end is the anode or cathode .
NPN  base to emitter.

|  /
|  \
    >


   Anode__> cathode


depending on which direction you want the diode to face is which way round you put it.
(my way of remembering is NPN=not pointing in)

"Would that work with, "dead" transistors where only two legs test as active and the analyzer identifies them as diodes?"

You have nothing to lose, the trannys dead so chuck it on the breadboard and try it.

[RRJackson]

You've got me in an Anything Can Happen Day kinda mood. Thanks! 

-Rob