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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.

Let's say I made an LPB-1 but converted to PNP Germanium, and biased "optimally", would the only difference between say a 40 HFE transistor, an 80 HFE transistor be the total dB gain available, or would saturation characteristic be different too?

I've been reading up on diode softness and curve tracing and all that kind of stuff. 2 threads in particular have made me question some of our understanding of practicalities of measuring the softness of the clipping/conduction knee. Take this thread for instance on MOSFET clipping, in this...

I'm curious how low HFE affects the sound of the circuit, I've never actually built, or really even engaged with Germanium type circuits before, I fall on 2 extremes when it comes to circuits, subtle "sweetner" type effects, over drives used as boosts, and tight metal distortions. It seems...

They're PNP unfortunately.

If anyone has followed my recent NOS [PNP] Gemanium transistor box adventures you would know I now own a large number of ~40 hFE, low leakage Germaniums. These are obviously not at all suited for Fuzz circuits, but that's ok, I like more subtle pre-amp like effects a lot of the time anyway. My...

I tested one of the PNPs (3AX31C) that I had tested on the TCR-1. The TCR-1 tested a hFE of 64 and an Iceo of 66uA. My Keen tester (assuming it worked) read a voltage of 0.075v with 2M2 floating and 0.566v with 2M2 connected to ground which would equate to a hFE of 49.1 and a leakage of <50uA...

Ok so I made the RG Keen tester, I think based on the continuity test, when the switch is in the up position, the bottom two poles are connected? And in the down position, the top two poles are connected? I wired it so the 2m2 is connected to the top lug, and the middle lug is connected to the...

Here's the results for the box of 100 1T313V, though there were 4 or 5, 1T313B sprinkled in. The data sheet suggested a hFE range of 20 - 250 so I had high hopes there would be a nice range of gains in the box. However, as you will see from the results, that was not the case. In fact I would say...

Bought a box of 50 П416Б Russian NOS Germanium Transistors from eBay. Spent the day in between working chucking them in the TC1 tester, so take the results with a grain of salt I guess. Apparently these are known for being low leakage, in fact the TC1 did not report an Iceo for most of them...

Would it be super gated essentially?

For more context, all of the Russian ones I've tested so far have been ND on the Iceo and I know they have a reputation for very low leakage.

I guess it would be nice if the NPNs were low leakage cause NPN germs are so rare. Guess I'll have to construct the RG Keen tester after all.

These are the results of my tests so far. All done on the TC1 edit: updated table ND means not detected / reported. Unfortunately I have no way to know if ND means the leakage is too low to detect or is crazy high.

Hmm so I've been testing the NPN versions the 3BX31C, and the TC1 doesn't detect the Iceo leakage on them, I'm not sure if that means the leakage is just very low, or if because it's NPN it doesn't think they are Germanium? Anyone got experience testing NPN Germs with a TC1?

Question for you. When might I want leakier transistors? Just took receipt of this haul and will test them before buying other Germs, but I guess might look into a small batch of GT402s. I'm mostly interested in preamp designs for both guitar, microphone, and live level. But everyone should...

Update, here's a re-test with the TC1. This actually seems useful? Having said that, they've just been sat at room temperature. Do they need to be used actively to stabilise?

This is the cheapest quality one I could find. https://nz.rs-online.com/web/p/rackmount-cases/8104264 No Tayda level stuff for rack enclosures it seems.