3AX31C Germanium gain

M

makisushi

Member
I ordered some germanium transistor from AliExpress before I knew eBay was a better source. The gain is all over the place with theses AX31C. I'm currently working on a tone bender and fuzz face pnp. Where should I start in term of gain ? I'm also waiting for more germanium from eBay
 

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I also bought a batch of these and had to trash most of them.

Which Tone Bender? There are at least 4 different circuits.
 
makisushi said:
The tayda one. Waiting for the pump charge inverter.
Click to expand...
Is the Tayda PCB a Tone Bender Mk. I? Mk. 1.5? Mk. II? Mk. III? Each one is a very different circuit. With that said, leakage will matter more than hFE. I’d recommend breadboarding the circuit before building it, especially if it’s not a Tone Bender Mk. III.
 
I don't know which version it is. They are using 3x 2N3904 for the NPN version, so 100 hfe +? . I use socket for the transistors so I can swap them... Does leakage needs to be high or low? do they all need to be around the same values or one pair and one other?

Tone Bender

This is the Tonebender, one of the most iconic fuzz effects from the 60s.
www.taydakits.com
 
here's the recommend value from Tayda but can I really use 3 differents gain with 2 bias?


Q1: β = 70-90
Q2: β = 50-70
Q3: β = 110-130
 
It's the MK2 then. A Fuzz Face with a transistor stage in front.
Those are the gain ranges. You want leakage in Q2 and Q3 above 100uA.
Q3 should be around -8V
 
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