Russian Germanium Content - Is This Normal?!

[Strange]

I sat down today to finally go through a pile of those good old Russian Germanium trannys that I picked up from a forumite a long time ago. These had already been audited for leakage and gain characteristics so I was simply determining resistor values for the classic Rangemaster circut in efforts of picking out a few tasty trannys.

So I am sitting down with my coffee and trusty multimeter and simply set my first resistor to 4K7 and see how close I could get with the +/- 68K value. To my surprise, all of the 108Gs biased up at -7V with the same resistor value (56K). I mean these were all very close and deviated at 0.1V to 0.2V difference. When I moved on to the lower gain 308Vs I was again pleasantly surprised that these all biased up in a similar regard (68K).

Does anyone else have any similar experiences? I expected way more deviation from device to device than what I actually found.

[rousejeremy]

I think they have some internal resistance that makes leakage hard to read. You might be better of using your ears in this case.

[Strange]

I have no problems with how any of them sound - they all sound decent to good - one sounds the best to my ears - with the values I biased them with.

[rousejeremy]

Then you found a keeper!

[Strange]

Has anyone else found these devices easy to work with?

[Colonel Angus]

I'll find out soon. I got a pile of them coming from USSR, should be here in a week. I've read a lot of different info regarding USSR GEs, but the consensus seems to indicate that leakage is very low for these devices. I suppose we'll see soon enough.

http://www.ebay.com/itm/310390948516?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

More available BTW. They might be awful, but at least it will be something to play with in PNP circuits before taking a soldering iron to a set of OC75s that basically cost as much as 50 of these

[pinkjimiphoton]

i bought a big bag of russian mp16b's, they're like 2n404 germaniums. they're all great, useful ranges, and i think it cost me like 5 bux for 40 of 'em!

[chromesphere]

I was thinking about getting a bunch of germaniums, dont suppose you have a link to those mb16'bs?  I found some on ebay they are about 20 for 16 shipped, random hfe i think, which still probably doesnt sound too bad from what i know...?
I'm new to germaniums and have NFI what im doing
Paul

[DDD]

Some of the Russian Ge BJT has special marks on the case - a star mark and/or a little rhombus.
These marking means a military standard trannies that many times are better than general purpose standard.
But, to be frank, I'm greately surprised with your situation.

[Toney]

 Hey Dmitriy, I remember some of your earlier posts re Russian germaniums.
I know the GT313 have an internal resistor that can affect readings but I thought the GT308 type did not.
Can you comment?

[pinkjimiphoton]

sorry, i bought more than i'll probably ever need, so no idea which vendor i got 'em from, i figured for the price, if i got screwed, i got screwed!

[Strange]

But, to be frank, I'm greately surprised with your situation.

No kidding - I still am surprised.

Edit: I will check my readings again today - perhaps I hadn't drank enough coffee at that point and i might have made an error.

[Earthscum]

Any chance anyone's come across low leakage (I can work with anything down to <2 gain) NPN Ge's? I wouldn't mind getting my hands on a dozen for Buzzards. I'm gonna order some of the ones Steve carries at smallbear, but a handfull for $20 or something like that would be a cool bonus.

[Colonel Angus]

http://www.ebay.com/itm/MP38-2N445-USSR-Germanium-NPN-transistor-Lot-20-/200713653741?pt=LH_DefaultDomain_0&hash=item2ebb774ded
http://www.ebay.com/itm/Mn38-GERMANIUM-NPN-TRANSISTORS-LOT-25-Hfe-40s-/160753044567?pt=LH_DefaultDomain_0&hash=item256da0cc57

looks like pretty low HFEs but the price is right.

[brett]

Hi
many of these devices were made from 1975 to 1990, and are vastly improved from old AC and OC devices from the sixties. As people have noted, leakage is negligible. They are also very quiet.
I haven't bought any Russian NPN devices, but if they were made after 1980 they should have benefitted from the improved technology of the time.
In my opinion, for building a Rangemaster or a Fuzzface the GT308 is the most consistent, best quality Ge transistor available.
cheers

[DDD]

I know the GT313 have an internal resistor that can affect readings but I thought the GT308 type did not.
Can you comment?

Wow! I've never heard of the GT313 internal resistor and never mentioned it in my posts (?). IMHO GT313 has no any internal resistor at all.
Here is an English description of GT313:
http://alltransistors.com/transistor.php?transistor=36068
--------------------
GT308 seems to be the best among Soviet Ge BJTs, especially GT308Vi (ГТ308В in Russian). It has a good beta and noise figures.
Description :
http://alltransistors.com/transistor.php?transistor=36045

[Toney]

You got my meaning slightly wrong: there was speculation that the GT313 and certain others have an internal resistor. Quite a few threads such as:
http://www.diystompboxes.com/smfforum/index.php?topic=62472.0

I remember that you are quite knowledgeable about these devices IE you would be able to answer 
Cheers for the links.

[DDD]

As far as I remember, there were some topics on the Soviet Ge trannies, and there were some opinions on the above mentioned internal resistor.
Today I've asked some experienced men, and all of them said there are absolutely no such a resistor in the Soviet RF Ge transistors such as GT313 and GT311, as well as in the lower-frequency ones.
Also they said that leakage currents and beta can vary greately even in one party of such a trannies (including military standard).

[IvIark]

My Peak DCA55 says there's an internal B-E shunt resistor in the GT313A's that I've got.  With the other Russian germaniums that I have there is no such reading.  These are the other ones I have:

GT108G
GT308B
GT309B
GT320B
GT322A
GT402B
GT404B
MP38A
P416A
P416B

[chromesphere]

Just pulled the trigger on 50 x GT108V's.  As i have no idea what im doing with these germ's i hope i bought the right ones.  Reported gains from other forumites seem pretty good.  They are 10v though which is cutting it close, but others are using them and seem to think they are ok.  Apart from that they are supposed to be low noise, low / almost non-existant leakage etc.   This is quite new to me but since i built my zombii fuzz with small bears US pair of germs, im excited to learn more. The texture / noise / oscillation of that thing is out of this world!
Paul