Germanium transistors

[Neagu Raul]

What do you guys think about germanium transistors?
Are there any rare ones the market is looking for or only the people using them for audio are interested in them?

 

[crutschow]

The are an archaic device and usually used only for replacement in ancient electronics.
The are seldom use for new designs as they have little advantage over modern silicon devices.

The may be some audio types who like them, but then those are often the types that also think they can tell the difference in sound between a ten dollar and a thousand dollar audio cable.

 

[gophert]

They are desirable for guitar effects pedals because they create distortion and many unusual sounds can be created. The distortion comes from the leakage, nonlinarity and poor temperature linearity. Ask ally they are crap and that crap is an easy way to make a bad amplifier - I think distortion pedals are the only “good” use for them.

if, however, you are taking about the new, SiGe high electron mobility transistors (HEMT), they are almost as amazing as Gallium Nitride transistors - but cheaper snd easier to make. They are strained silicon lattices and allow higher current at lower on-resistance. They will likely be limited to high frequency CPU and radar applications.

 

[Neagu Raul]

I had a tought that maybe i can rebuild a Romanian scope with some germanium transistors but if i can't rely on them, i guess the trace might go wild on the screen
I have a E0102 oscilloscope and i had this on my mind... to make it out of smd's or germanium. Maybe i can find some paired germanium transistors and work with them but i think that would be expensive. Would anyone buy it ?

 

[rjenkinsgb]

The specifications for germanium transistors are very poor compared to modern silicon transistors. The only reason to use germanium parts is repairing/restoring equipment that was designed for them.

I got a big batch a couple of years ago to repair a part of an old Eastern European machine; I was intending to replace all the transistors in the faulty board.

It turned out that only around a third of the "new" parts were usable, most had abysmally high leakage and were not good enough. The original parts were generally better, other than the ones that had totally failed.

There is no good reason to use them, for anything really..

 

[Neagu Raul]

Do people just trow them out?

 

[Nigel Goodwin]

Do people just trow them out?

We did, where I used to work - although by 'throw out' we actually threw them to someone else - along with everything else when we closed. But among all the stuff was a draw full of germanium transistors left over from repairing radios and record players etc.

 

[AnalogKid]

Compared to silicon devices, germanium ones have a lower forward voltage and a "softer" knee, the roundness of the onset of forward conduction. Both of these are desirable characteristics for a guitar effects pedal. The lower forward voltage and saturation voltage in a power transistor means less power dissipation. Back in the 80 or 90's's, one company promoted them heavily in the switching power supply and motor drive markets; geezers around here will remember "Oliver Germanium".

ak

 

[Neagu Raul]

I was asking because i started collecting vintage germanium transistors after my grandpa died, he had an old romanian radio with some pretty nice EFT323's and AC180/181K's in it and i tought i can just take them out and reuse them but they hold a sentimental value so i never used them, i just started collecting some nice transistors over the years and now i have some pretty nice pices and wanted to know if I am the only crazy guy doing this ))))

 

[Nigel Goodwin]

I was asking because i started collecting vintage germanium transistors after my grandpa died, he had an old romanian radio with some pretty nice EFT323's and AC180/181K's in it and i tought i can just take them out and reuse them but they hold a sentimental value so i never used them, i just started collecting some nice transistors over the years and now i have some pretty nice pices and wanted to know if I am the only crazy guy doing this ))))

AC180/181K were the 'later' Germanium devices, output transistors for radios and record players, and replace the AC128/176K - the 'K' meant they were in an extra square casing, with a hole in for bolting to a heatsink.

As for 'the only crazy guy', the one who had all the stuff from where I used to work never throws anything away - his place is unbelievable - stuff piled up everywhere, and it's a pretty large building. In fact, with the demise of TV repairs (which is what he still does) we've taken to passing him some manufacturing work for us - it's a 'win/win', he gets some much needed cash, and it allows us to turn round orders faster.

 

[Neagu Raul]

Good to know i am not alone)))

 

[schmitt trigger]

I do remember good 'ol Oliver Ward, a.k.a Oliver Germanium.

His company Germanium Power Devices, advertised heavily in trade magazines.

 

[Nigel Goodwin]

I do remember good 'ol Oliver Ward, a.k.a Oliver Germanium.

His company Germanium Power Devices, advertised heavily in trade magazines.

Presumably it was an American company?, I've never heard of it - and google hardly has either

So I presume the Germanium thing was a failure?, as you'd expect.

 

[schmitt trigger]

Don Lancaster once wrote this about the CK722, a very popular Ge transistor:

“The nice thing about the CK722 was that you did not have to worry about bias.
ICBO took care of it for you.”

 

[sarahMCML]

Tested half a dozen of my father's ancient Ediswan XA102, XA103 and XB104 germaniums yesterday on a cheap Chinese tester. All still worked, with the lowest an hfe of 24 and the highest 140, and 1 with 0.02mA leakage. Not too bad considering they're over 60 years old!

 

[Neagu Raul]

Does anyone have a CK703?

 

[gophert]

Does anyone have a CK703?

If somebody does have one, I hope they know how valuable it is. Every component collector wants one

 

[Neagu Raul]

How much does it cost? I've never seen one on the market...

 

[Nigel Goodwin]

How much does it cost? I've never seen one on the market...

I've never even heard of one?, presumably it was an American device?.

 

[gophert]

It was the first transistor on the market by Raytheon. Mostly Ute not museums and rich private collectors. There are a few former HP, Motorola and Fairchild engineers/executives that collectors. I’ve sold some early parts to a few. I once stumbled on a salesman’s kit for the first Red LEDs from HP and, after finding the right people, it ended up with someone who will take good care of it