Donate or sell them to a historical radio society or a museum if you don't want to use them yourself.
Damn it! I could swear it's used just for FIR not NIR or Gamma radiation ... Thanks for letting me look up the proper information! I need to revise my old knowledge.
https://www.stsci.edu/stsci/meetings/space_detectors/gdfi.htmhttps://www.google.com/url?sa=t&sou...0QFnoECA0QAQ&usg=AOvVaw0Gk6x-kaMk5QvbgfQg1x4v
https://www.google.com/url?sa=t&sou...0QFnoECAMQBg&usg=AOvVaw1fy0nTZcMpX7dW5ZfM795Whttp://www.teledynejudson.com/products/germanium-detectorshttps://www.newport.com/n/ingaas-vs-ge-ir-detectorshttps://www.google.com/url?sa=t&sou...0QFnoECAwQAQ&usg=AOvVaw1rdciCFa_LjJFziSrYlob2
https://arxiv.org/pdf/1809.03046
There are thousands of pages of such detectors mostly used for military or space equipment and indeed they have almost nothing to do with the 60's transistors...but their sensing temperature properties are as predictable as silicon ones just faster so the fast current drift due to temperature of a germanium transistor should be naturally sensed better with a similar germanium device. The fact that very few audio companies used germanium transistors for superdiode thermal compensation of final power stages was due to the prohibitive cost of the germanium transistors at the time while NTC resistors were far cheaper to make.In the 60's or even 70's early silicon transistors all electronic equipment mentioned how many transistors had inside to justify the price of those components as they were pretty expensive.
Hi , Parkerdiy ! I see that this topic was started a year ago. And if you haven 't decided to build a germanium preamp , I want to say this . Don 't listen to the skeptics . Germanium preamps sound good and their construction even now still makes sense . I say this as a person who built 6 phonopreamps on germanium transistors . I have preamps on JFET and silicon bipolar transistors . But I really like to listen to records through germanium preamps . The result by sound - justified all efforts .
First, Germanium transistors are mostly out of production, so what is available is limited in choice.
Second, they needed protection against atmospheric conditions, metal can was needed. Plastic Ge types are really rare.
Third, I think Germanium lost its purity over time.
So do your preparation, obtain all the devices you need, and a few extra, and make yourself happy, in the sense that enjoy listening to something you actually made.
That is a different kind of satisfaction, is it not?
Second, they needed protection against atmospheric conditions, metal can was needed. Plastic Ge types are really rare.
Third, I think Germanium lost its purity over time.
So do your preparation, obtain all the devices you need, and a few extra, and make yourself happy, in the sense that enjoy listening to something you actually made.
That is a different kind of satisfaction, is it not?
First , the acquisition of germanium transistors is not difficult . In the USSR , the production of germanium transistors continued until 1991 inclusive - I have such copies . A huge number of them were produced , and although many were scrapped in the 1990s and 2000s, there are still a lot left . And they are inexpensive ( especially in Russia ) . In order to do something , you just need to want to do it ..... Secondly , the transistors of the USSR were made qualitatively - many types had leakage currents much less than those of the AC-122/ AC-151 transistors. This is a fact that I have been measuring . To build my germanium preamps - I had no problems with purchasing transistors . You can view some of these preamps here - https://www.lencoheaven.net/forum/index.php?topic=36187.0 . And as I have already written , I also have silicon products , but I listen to germanium more often .
Russian audio quality was terrific, a fact not well known to the West.
Many components were nearly interchangeable with Western parts...same performance.
1991 was 30 years ago, so some changes may have occurred (it seems that happens whether or no it is in circuit).
Test them and make them sing!
Many components were nearly interchangeable with Western parts...same performance.
1991 was 30 years ago, so some changes may have occurred (it seems that happens whether or no it is in circuit).
Test them and make them sing!
Of course , many years have passed since 1991 . But I 've bought more than 200 germanium transistors in the last few years . They are on sale now .
Over the past few years ( in the manufacture of preamps ) - I measured a large number of germanium transistors . All transistors manufactured in the USSR were in order - not one was rejected .... Among several dozen pieces of AC122 / OC-1071 /OC-1044 - several transistors with very large leakage currents were found - the leakage was much greater than indicated in the datasheet. But these are only a few pieces . Everyone else was fine . And the selection of these transistors by parameters is not difficult . This procedure is much easier than selecting tubes for an amplifier . For example, matching pairs of identical JFET transistors is much more troublesome than measuring germanium transistors.
One of the popular silicon phonopreamps ( Elektor Preconsonant -1978 ) was successfully assembled on germanium transistors . Of course , some changes had to be made to the scheme . https://www.lencoheaven.net/forum/index.php?topic=38309.60
Germanium transistors are a fine thing. Unfortunately, they are only available in old package types, which are disadvantageous in terms of sound: more undefined current: more undefined signal.
If I would build trannies, I would like to use germanium, but in current respecting packages. One chance: mill the housings, cut.
One conceivable advantage: the lower "bias voltage", about 0.3 volts.
Another advantage: (at moment) no complementary transistors, so no complementary transistor push-pull amplifiers, whose half-waves sound very different, which has nothing to do with "high end".
If I would build trannies, I would like to use germanium, but in current respecting packages. One chance: mill the housings, cut.
One conceivable advantage: the lower "bias voltage", about 0.3 volts.
Another advantage: (at moment) no complementary transistors, so no complementary transistor push-pull amplifiers, whose half-waves sound very different, which has nothing to do with "high end".
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Also, GT402/404 and some other Soviet transistors that were in production until relatively recently.
I’m not entirely sure that the old Ge processes would even be compatible with modern epoxy over-molded packages. All those old hard to work with packages were air cavity, and I sure don’t recall any TO-92 Ge’s. So I doubt the TO-3P would fly, and they’ll have to stay in metal cans.
Complementary transistors are not required to get symmetrical waveforms, if one is open to the use of transformers. A pair of the same PNP match better than any so-called complementary. Iron was cheaper than germanium (and much cheaper than silicon) in the old days. You can still get it, you just have to pay for it. Even at $25, a driver transformer may be cheaper than an NPN Ge transistor these days. Especially one good for 10+ watts output.
I remember 2SB56 transistors in electronic project kits. The 0.2V Vbe was advantageous with battery power. Otherwise, germanium transistors had high leakage currents and easily went into thermal runaway. I was happy when silicon transistors became widely available.
Ed
Ed