what can I do with a box of very old germanium transistors?

[Mark Hennessy]

What about AC176 and AC128 NPN and PNP.
I have 30 - 40 of each, never used. I got them from a collegue of mine who at some long time ago worked for B&O.

I use them for restoring old transistor radios from the '60s and '70s. Let me know if you'd like to part with any.

Omg that looks like new! Great restoration work! I bet it looks even better inside!

Thank you 

Rather than taking this thread OT, I'll point you towards the story and more pictures here: http://golbornevintageradio.co.uk/forum/showthread.php?tid=653

I do many other things besides restoration work, but I do find it relaxing and therapeutic. It makes a nice change to deal with older components and techniques, and you really have to admire the designers who were still new to transistors and didn't have the tools (hardware and software) that we have today.

When people talk about the "germanium sound", I suspect that has more to do with the topologies that people were using at the time. For example, a lot of audio amplifiers in those days were using interstage coupling transformers, which restricts the amount of negative feedback you can safely apply. And transistors were incredibly expensive at the time (several £s in today's money) so designers used them very sparingly, which sometimes leads to higher noise and distortion levels that we're used to today. Of course, coming from the valve/tube era, designers were used to getting the most performance from a single active device.

[SL4P]

Good for white noise and pure random number generation...!

[German_EE]

Build a Deacy Amplifier

https://en.wikipedia.org/wiki/Deacy_Amp

[calexanian]

BTW 2N585  is £7 GBP / piece on Ebay. There is definitely a market for old parts especially for "authentic" restoration.

Is there something unique about OLD germanium transistors? Can they be used for niche apps like avalanche pulse generators, noise sources, some other solid state physics experiments etc. where modern versions don't work as well?

Apart from what the purists will tell you about the sound of germanium transistors in fuzz circuits and the like the main technical reason to use them as replacement parts is that the circuits that use them are often designed to take advantage of their very low BE voltage threshold. Using a silicon pnp device may result in improper biasing in linear circuits. I just cleaned up a radio from the Datsun roadster I am restoring. Built in 68 with just 7 transistors. All germanium. It actually sounds quite good for such a simple design. They truly did more with less in those days.

[CatalinaWOW]

How about a thermal runaway demonstrator?  Making one of these run away is easy, the fun part would be putting the controls on so you didn't use up one of your stock each time you demonstrated it.

Thermal runaway was the reason silicon took over from germanium.  One of my professors was an early TI employee and he told a great story about how TI combined technical expertise with commercial subterfuge in those first commercial silicon transistors.  At the time the problem was getting silicon pure enough to then dope and get good junctions.  Zone refining was the technology of the day, but single passes weren't delivering the desired results and multiple passes would not be commercially viable in the long run.  To get to the market first, and to give the impression of a greater technical lead than they actually had at the time they set up a convoluted scheme where silicon boules would be run through the zone refiner, then spirited off to a "storage room" where the serial numbers on the boules where changed and a secret set of books kept.  After several passes through the refiner the boules were of the desired purity.  The process gave the impression of both a high level of production and of a superior refining technology.  Eventually the processes were dialed in and the financial results began to match the show which had been put on.

[krivx]

BTW 2N585  is £7 GBP / piece on Ebay. There is definitely a market for old parts especially for "authentic" restoration.

Is there something unique about OLD germanium transistors? Can they be used for niche apps like avalanche pulse generators, noise sources, some other solid state physics experiments etc. where modern versions don't work as well?

Apart from what the purists will tell you about the sound of germanium transistors in fuzz circuits and the like the main technical reason to use them as replacement parts is that the circuits that use them are often designed to take advantage of their very low BE voltage threshold. Using a silicon pnp device may result in improper biasing in linear circuits. I just cleaned up a radio from the Datsun roadster I am restoring. Built in 68 with just 7 transistors. All germanium. It actually sounds quite good for such a simple design. They truly did more with less in those days.

Keep in mind the fuzz circuits are absolutely not linear circuits, nor are they meant to be. The original designs were usually very simple (2 or 3 transistors) and tended to vary with transistor parameters. You can rework them for Si parts but usually you get something that works differently (not necessarily better or worse as that's just preference, but just different).

FWIW when I've built this stuff I have been happy with Russian parts, they seem to have continued producing general-purpose Ge parts into the 1980s and the devices are very consistent and conveniently quite cheap. I understand why people like "original" replacements for aesthetics in old equipment or replicas of old equipment though.

[MrSlack]

Build a joule thief that beat those silicon based ones with lower start up voltage. 

Neckbeard time...

Germanium transistors would probably die after about five minutes doing that. They died everywhere else.

My first experience was with AC127/AC128s  salvaged from radios from jumble sales in the early 1980s. Half of them didn't work at all to start with, about half of the other half barely worked and the half of the remaining half worked but only for about an hour. And the successful few? The moment you went near them with the primitive Tandy firestick I had, they died instantly. Apart from an AC128 I had which was named for prosperity (Dave ironically) because I couldn't kill it.

Then I spent 10 quid on some 2n2222 units from Tandy/Radio Shack and never looked back other than to lament the repetitive shafting because I bought a sack of 200 Fairchild bc337s from Farnell a few weeks back for the same cash. Ugh.

Back on topic, sell 'em to audiofools. I did that it about 2009 on eBay when there was 'peak pedal' and got £5 a transistor. I have been considering buying bulk soviet germanium stuff (Tesla) which is pretty close characteristic-wise from a friend I have in the Ukraine and selling it in Western Europe as the new sound. But then the shame sets in.

[calexanian]

Speaking of early tom foolery in semiconductor sales, I heard in an interview from the computer history museum that the salesmen would sabotage competitors products by various means. The old epoxy blob UFO shaped transistors could be damaged by flicking the top just right. The early TI metal can types could have their characteristics changed by squeezing them between your thumb and forefinger making design engineers think the parts are not holding spec in their designs and going with other parts the salesman just happened to have with him, etc. Wild days. One of the ladies we have had do assembly at our place for 30 years now used to work at Fairchild in the 60's and told us stories i never believed, until I learned the story about the Traitorous Eight. Crazy times.

[MrSlack]

Interesting times indeed. Never trust a salesman!

[Halvmand]

What about AC176 and AC128 NPN and PNP.
I have 30 - 40 of each, never used. I got them from a collegue of mine who at some long time ago worked for B&O.

I use them for restoring old transistor radios from the '60s and '70s. Let me know if you'd like to part with any.

Good work on that restoration.
If we can get them shipped to the UK then they're yours. Given the answers in the thread, I don't think I'll ever use them. Ill keep a couple though.

[Mark Hennessy]

What about AC176 and AC128 NPN and PNP.
I have 30 - 40 of each, never used. I got them from a collegue of mine who at some long time ago worked for B&O.

I use them for restoring old transistor radios from the '60s and '70s. Let me know if you'd like to part with any.

Good work on that restoration.
If we can get them shipped to the UK then they're yours. Given the answers in the thread, I don't think I'll ever use them. Ill keep a couple though.

Thank you - that's very kind. I'll send you a PM 

[IdahoMan]

I have a VT-51 Megaphone (rectangle-shape) that does not work. When opening the battery compartment there are two 2SB337 power transistors sitting atop the inside casing. Googling them, they appear to be germanium.

Should I suspect them as the problem, or some other cause?

The megaphone is dead as a doornail. When germanium transistors fail or are failing, what are the symptoms?

I also have a large, portable "all transistor" Zenith shortwave radio. It is germanium, and has a positive ground?

Thank you.


Sincerely,
IM

[jonovid]

They are actually in great condition, given the age. Unfortunately, not much practical uses.

never throw out old electronic components that are in a never used condition & more than 40yr old . very rare electronics - the economics of scarcity =$