GE Transistor in SD-1 Mod

[seanm]

Keeley's SD-1 mods mentions replacing D6 with a GE transistor. Does it matter much what model of transistor? I have some old 2N571s that are listed as being "PNP GERMANIUM RF/IF AMP".

I know I should just try it, but I was looking for some pointers.

[cd]

Nope.  The transistor is used as a diode.  Good way to use up the Ge transistors that are leaky or don't measure up to Fuzz Face/Rangemaster/etc. specs.

[seanm]

I figured as much. Thanks!

[petemoore]

Sounds like a B/E junction used as a diode, that's how I get service from old FF and TB and Rmaster 'reject' Ge's...use 'em as diodes.
 I once used a Ge as an input buffer on an SD-1...never extensively tested that, made a just noticable difference IIRC.

[seanm]

Sounds like a B/E junction used as a diode, that's how I get service from old FF and TB and Rmaster 'reject' Ge's...use 'em as diodes.
 I once used a Ge as an input buffer on an SD-1...never extensively tested that, made a just noticable difference IIRC.

When I was first moding the SD-1 I added a blend. I noticed a big difference with the opamp as the input buffer. I then tried a JFET and didn't really notice a difference

How about the caps? Keeley recommends metal stack film. What is the advantage of metal stack film over poly film?

[RobbieD_216]

I'm also looking into these mods. I am from Sydney and having problems finding anything along the lines of a Ge transistor at all.  I went onto smallbearelec and noticed a dew different types. Does anyone know what the difference is?

[Rick]

Does anyone know if using a really leaky germanium transistor as a diode
will usually make a great germ diode? Or can the junction used (base - emitter etc.) be less than perfect in these leaky ones? Sorry I have not
tested any yet in this configuration (I will test some) - but just looking for others with previous experience with this.
Anyone? ...Rick

[stumper1]

Is there any difference between a Ge diode and Ge transistor wired as a diode?  I don't have any Ge transistors and they are alot more expensive than a diode.