Using AA119 to substitute 1n34 diode

cytt0rak · April 30, 2017, 08:31:31 AM

Hello I found some AA119 germanium diodes, could I use it in place of 1n34 diodes?

GibsonGM · April 30, 2017, 08:52:54 AM

If you come across this kind of problem, you might try to find the data sheet online and post a link with the question!

It also depends WHERE in what CIRCUIT you want to replace them, too...

The odds very high are that you CAN replace a 1n34 with this type...what I would do is first, measure the diode's forward voltage drop (Vf) and see if it is close to that of the 1n34, which is given as about .3V. If it is in this area, you should be ok. You can always just try it as a clipping diode, no harm, altho if Vf and a couple other parameters are too far off the distortion may not sound the same as what you're trying to re-create.

rankot · May 10, 2018, 04:30:22 PM

I've bought few Chinese Ge diodes, claimed to be 1N34A. They look like Ge, but I am not sure if they are the right thing. Datasheet for 1N34A says Vf at 7.5mA is maximum 1V (not stating average?), while I got some 0.6 with those diodes. I also have few AAZ24 Ge (definitely Ge) diodes made long ago by Yougoslavian factory EI Niš, they show approx 0.3 Vf at 7.5mA. I also checked 1N270 datasheet and it also has only max Vf declared. How to know if those Chinese diodes are really Ge? I am almost sure they are fake, but I need someone with more experience to clarify this to me

This is how they look like:

Kipper4 · May 10, 2018, 06:09:23 PM

I think the ones i bought years ago are chinese "fakes" too.
But boy do they sound good where I put them in circuits requiring these 1n34.
I'll let your ears be the judge.
If they measure up? Whop 'em in, what have you got to lose If you got 'em.

Couldn't confirm or deny a "fake".

chromesphere · May 10, 2018, 09:15:16 PM

There are so many 1n34a's its hard to pinpoint what should be a 'correct' fv and what's not (at least from what I've seen), if there even is such a thing. I believe genuine 1n34a's have some pretty wild Fv variance!

Anything that comes DO-35 (DO-204AH) packaged is obviously not. These are the fakes I see all the time. I have not encounted DO7 "1n34a" diodes that are not germanium, not to say they don't exist I just haven't seen them before. You could try the heat on them. I've found though even that's not totally accurate, at least not with my DMM (even silicon's can move a bit).

MaxPower · May 10, 2018, 09:42:44 PM

I've tried the two types that tayda sells (ge diodes) and one type sounds good but I didn't like the other. I think they both measured about the same vf. Mayhap they're trying to sneak a schottky past us? Or do some ge diodes just suck?

Rob Strand · May 11, 2018, 12:16:54 AM

It is almost impossible to detect a real Ge diode from a Schottky from the diode voltage at low currents. It's not until you get to about 10mA that things start to become clearer.

Notice how the Schottky voltage is still low at 10mA

Rob measurements (2001)
Unmarked glass Ge diodes. One green stripes and one black stripes
BAT46 is a small-signal Schottky
I [A]   Vge(grn1) Vge(blk2) VBAT46
10u    0.09     0.07 0.13
100u 0.19 0.16 0.20
1m   0.41 0.32 0.27
3m   0.663 0.492 0.311
5m 0.863 0.628 0.34
10m   1.25 0.91 0.40

Even for the larger Ge diodes the voltage starts to take-off at 10mA
1N60 datasheet typ.
0.6V @ 5mA
0.82V @ 10mA
(You might see 0.4V @ 10mA on some but these are deceptive Shottkys I believe.)

Russian Diodes:
The 1N34A in this thread only has a 0.46V voltage drop at 10mA. This is very much on the low voltage side and I'd even start to doubt it.
https://www.diystompboxes.com/smfforum/index.php?topic=118007.0

Fake 1N34A?

https://www.diystompboxes.com/smfforum/index.php?topic=113234.0

http://www.oldradioworld.de/gollum/fig04.jpg

rankot · May 11, 2018, 01:57:24 AM

This makes sense, and means that my Chinese diodes are probably really Ge, but still have no idea which exact model. I have two types, one is with one red stripe, another one with two black, and measurements are almost the same. I believe they are DO7, since they are approx. two times bigger then regular 1N4148, and point contact wire is clearly visible inside.

Somehow I thought that Ge diodes shall have low Vf, like Schottky, but it seems I was wrong.

Rob Strand · May 11, 2018, 02:57:28 AM

QuoteSomehow I thought that Ge diodes shall have low Vf, like Schottky, but it seems I was wrong.

They do but only at low currents.

QuoteI've tried the two types that tayda sells (ge diodes) and one type sounds good but I didn't like the other. I think they both measured about the same vf. Mayhap they're trying to sneak a schottky past us? Or do some ge diodes just suck?

Some companies have been very sneaky. They have 1N34 and 1N60 diodes but if you look at their datasheets they are marked Shottky diodes. So they are sneakily redefining what those part numbers mean. The people that do the buying for companies like Tayda, ~~Mouser~~ etc. should be aware of this practice and reject those manufacturers, not go along with them. If your order says Germanium diodes and you get Shottky diodes then you have not been supplied the correct part!

Rob Strand · May 11, 2018, 03:49:18 AM

Here's some original Sylvania diode data (1N34):

Original Telefunken Data (AA119):

[Edit: one more]
Toshiba Data (1N60):

chromesphere · May 16, 2018, 05:40:39 AM

A friend in Japan found some 1n34a's and sent me a few in the mail by surprise, i got them today. Im not sure of the brand, could be toshiba. Heres an example of how far they can vary, PN junction I/V test on the DCA45. I have seen other brands vary even more drastically.

thermionix · May 16, 2018, 06:05:36 AM

Paul, can your friend in Japan find any Panasonic MA150s? They are simply unavailable here in the US.

Rob Strand · May 17, 2018, 03:03:26 AM

QuoteA friend in Japan found some 1n34a's and sent me a few in the mail by surprise, i got them today.

Pretty cool the middle of your results is close to the datasheet (which is typ.)

MaxPower · May 17, 2018, 02:26:37 PM

Forgot about this thread. I tested my diodes (the 1n270's and the 1n34a's). I used a 680 ohm resistor in series with the diodes (one at a time) using a 9 volt battery. I measured about 11ma of current with each and about 1.0 volt across one diode and about 1.1 volts on the other. This time they both sounded similar. I don't know why the previous time the 1n34a sounded horrible to me. Must of been the test circuit I used or was just having a crap day. So, yeah, I guess Tayda did give me germanium diodes. Or I don't know what ge diodes are supposed to sound like, which is always a possibility...

Oh yeah, the battery tested as being 9.00 volts. Never had that happen before. Well, I don't know! Seemed noteworthy at the time... lay off me...

chromesphere · May 17, 2018, 07:32:28 PM

Quote from: thermionix on May 16, 2018, 06:05:36 AM
Paul, can your friend in Japan find any Panasonic MA150s? They are simply unavailable here in the US.

Hey mate, I asked, he said this particular electronics store doesn't have any but he will keep an eye out for them. If they show up ill pm you.

thermionix · May 17, 2018, 07:39:50 PM

Quote from: chromesphere on May 17, 2018, 07:32:28 PM
Quote from: thermionix on May 16, 2018, 06:05:36 AM
Paul, can your friend in Japan find any Panasonic MA150s? They are simply unavailable here in the US.

Hey mate, I asked, he said this particular electronics store doesn't have any but he will keep an eye out for them. If they show up ill pm you.

Awesome, thanks!

PRR · December 25, 2018, 02:27:57 PM

FYI-- In 1948 (early commercial availability), 1N3x were sold in "tiny fuse" packages.

Before that GE diodes were in machined brass shells (not as "1N34").

The glass package came later.

PRR · February 07, 2022, 02:45:04 PM

One year before: conflicting pictures. The drawing shows an unspecified thin sleeve with wax seals. The photo shows a fuse-like mounting.

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Using AA119 to substitute 1n34 diode

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