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Alright, back with another round of Ge transistor testing this time the GT309B. These were quite a bit more expensive per transistor than the previous boxes I purchased. However if you want higher gain but low leakage these definitely seem worth taking a risk on. Out of 20, only 1 device is...

Hey folks. I built my first ever bread board circuit, an LPB-1 and tested the NPN 3BX31C. It biased up nicely, here's the oscope results, 1000khz 0.6v P-P signal input 1000khz 1.2v P-P signal input Haven't measured the biasing resistor values yet, but seems like the low leakage readings...

This quote on an old thread discussing diode Vf and knee made me realise, in a lot of circuit analysis, a lot is mentioned of the voltage but rarely the current. It made me want to do some simulations and examine this topic further. Thing is I've only ever used LiveSpice, does any have a SPICE...

Yeah there's no reason the design needs to be all Germanium, would be fine to use a JFET input buffer for instance, and a Si BJT follower to buffer the output.

Could be fun, any sweet example circuits? I probably have like 100 devices in this range, so I could make quite a few things ha ha. Would really love to do a microphone preamp, and line amp too.

In the above examples though, the clipping would be symmetrical in both typologies though right?

Hey folks, just looking at this "tape simulator" schematic, the original schematic is on the left, what I'm wondering is, would there be any difference compared to the version of the right? I'm vaguely aware of the concept of diode ladders, but usually I think there are some resistors in the...

The other thing of course is, I'm not married to 9v. Using an external supply and an LT1054 means that anything up to 15v is possible, not sure how that affects things but maybe it will help these lower beta devices be more useful.

I think you would treat the composite like this, using the marked point as Bass, Collector, and Emitter for the test.

Yeah, I hate the idea of these devices just rotting away doing nothing. I know we have a tendency match a device to the circuit, and not the other way round, but that seems so wasteful? Surely there are some clever circuit designers around that can make these things useful.

Nice! I wonder if bootstrapping and/or negative feedback can help stabilise low Hfe Ge Transistor circuits. I'm curious eventually to make a cascading preamp design similar to the JFET amp simulators and see how it sounds.

How did vintage Fuzz Faces and Rangemasters handle this problem then? Given they would be connected to an amplifier down range? Once I built something permanent I will definitely use the charge pump inverter.

Nice, been interested in a Vari-Mu type thing.

Diezel and VHT sort of share a similar sound in my opinion, that dry percussive Marshall on 11 type of thing. I think the Valhalla is a good shout.

Ok, so I have decided to try my hand at the PNP Ge LPB-1 breadboarding. And wouldn't you know it, there's already a guide to do that (sort of) https://barbarach.com/npn-to-pnp-transistor/ I wanted to ask a clarifying question though, in this example below, this to me looks a lot like the...

Have yet to put any of these devices in a circuit. Funnily enough I'm not a big fuzz guy, I prefer the more "preamp" type stuff. I have so many on hand though I will likely give it a try.

Also very true, given how much signal amplification is happening before diode clipping, the softness or not probably has diminishing effects on the actual output.

Regarding the feedback, these Russian Germaniums have almost undetectable leakage so I'm guessing the negative feedback will be an important parameter.

Absolutely! I guess what I'm saying is, there seems to be some conventional wisdom that actually doesn't hold true according to some testing. For instance this statement: https://www.diystompboxes.com/smfforum/index.php?msg=1148986 I've heard many times that stacking diodes not only...

I actually do have a breadboard but I've never used it, but this whole endavour has deffinitely ignited my urge to learn. I've learned a lot since I first bought them so breadboarding seems a lot less intimidating now.