Russian Diodes for dummies

[jubal81]

Did you measure the leakage of any of the germanium diodes?

The 1N270-NOS looks more like a resistor than a diode, for example, and others have similar appearances that stray away from the typical diode junction conduction. Could this be due to leakage currents?

Best regards, Jack

Looking at the same thing. The D9B and D9G I've tested are among the leakiest Ge didoes I've found.

[diy-tubes]

If I'm not mistaken we can measure if everything is ok with ge diodes using multimeter as ohmmeter: D9J gives above 100k wich usually is ok for germanium.
Datasheet says max I(rev) or I(leak) for: D9B,V,G,D,E,J,L - 250uA, D9i - 120uA, D9K - 60uA.
1n34a datasheet says 30-500uA. 1N270 - 100uA max. BTW my diodes I've got from my HK supplier looks like DO-7 1N34a too - two black bands on enhousing... Anyway I'm sure about russians - NOS, OTK, from sealed boxes etc.
Sure Si diodes rev resistance is much more higher, but we are looking for germanium diodes, do we? 
PS: Please correct me if there's any mistakes, I've never thought about ge diodes leakage in this domain. Perhaps multimeter measerement method is wrong, or Peak Atlas DCA75 draws wrong graphs, please let me know how to measure it correctly. What did you mean by saying "The 1N270-NOS looks more like a resistor than a diode"? Thank you!

[Fernando]

Hello Ivan and all,

I have what seems to be genuine NOS BKC 1N270, but most of them (20 units) read 0.236V in my meter (Meterman 37XR).
Should they read 1.10V? (as your plot shows for NOS 1N270)
Also, they have one thick black line, not two, and have printed "BKC 1N 27 0".
Are they "well made" fakes? Are they real BKC but "modern"?

I'd like to experiment with good 1N270 but not sure if this are real NOS ones...

# edit: now that I see my meter test diodes at 1mA, 0.236V@1mA may be OK for NOS 1N270...
I mean, in your curve plots, the NOS 1N270 reads 1.10V but at 12mA, not at 1mA, am I right? #

This are other readings with the same meter (*) :

D311: 0.17-0.18V
OA7 (Valvo): 0.23-0.24V
AA117: 0.23-0.24V
1N270 (BKC): 0.236V
SFD107 (Thomson): 0.35-0.36V
1N457: 0.62-0.63V (Si, for reference)

* Meterman 37XR specs for diode test:
Test current: 1.0 mA (approximate)
Accuracy: ±(1.5 % rdg + 5 dgts)
Resolution: 1 mV
Open circuit volts: 3.0 dc typical

More diodes tests.
1N60 reissue (China), 1N270 reissue (China), 1N270 NOS (two black lines, housing similar to Russian GE diodes) compared with 1N34A, Russian D9E, D9J and si 1N914.

[italianguy63]

Just be careful though, the line on the Russian diodes is generally the anode side, not the cathode, like we're used to. Best test before using them, unless in an opposing pair scenario where it won't matter.

Hey Dino.. thanks for this.  I recently got a batch of D9B's.  Put them in an Octavia.. and it sounded a little "off".

Checked, and indeed the banding on them is reversed!

Good catch.

MC

[Fernando]

Ivan, one more thing.

In two of your plots, the D9V and the D9J seem to be exchanged.
Is this a mistake or just two very different readings of each so they swapped positions in the plots?

Thank you

[Fernando]

hello? llo llo llo llo

someone around? ound ound und nd nd

[digi2t]

hello? llo llo llo llo

someone around? ound ound und nd nd

[diy-tubes]

Sorry guys for slow answers, I will try to find some time to check diodes mentioned and add more plots.
Thank you for your feedback!

[Fernando]

Thank you very much Ivan.

I explain my doubts/questions in my post above (Reply #22 on: 18-08-2018, 07:18:58)

Best,

Fernando

Sorry guys for slow answers, I will try to find some time to check diodes mentioned and add more plots.
Thank you for your feedback!

[zedsnotdead]

Another picture. Added D2D, D18, D311. I will offer diodes kit if it's interesting, so everyone can test them.

I was searching for D2D curves but I can't find them in the graph...

[MJ_Sound_Cubed]

Good read

[Fernando]

Ivan and all, here are two more readings @1mA (can't edit my post above, #22) :

D18:  0.30-0.34V@1mA  (glass capsule covered in black rubbery material, white letters "Д18")
AA119:   0.33-34V@1mA * (Siemens NOS, glass, slightly green tint with light red print "AA" "119")

For my readings, I test at least 20 diodes of each type.


(*) Datasheets say 0.56V@1mA typical for AA119, but this is my reading...

[thermionix]

Another picture. Added D2D, D18, D311. I will offer diodes kit if it's interesting, so everyone can test them.

I was searching for D2D curves but I can't find them in the graph...

I'm wondering if you took a dozen of the same type, the curves would be almost as varied.

[diy-tubes]

Ivan, one more thing.

In two of your plots, the D9V and the D9J seem to be exchanged.
Is this a mistake or just two very different readings of each so they swapped positions in the plots?

Thank you

Yes mistakes are possible. I will check them again and add missed D2D.

Meantime another picture. 1n34a, D9E compared to D9i and D9g


PS: What about your question about 1mA tests, it seems that your measurements are ok. Please check zoomed pic from DCA75. D9E is about 0.29V at 1mA

[diy-tubes]

Tested D9J and D9V again. Just to note - ge diodes have the same deviation as transistors' hFE 
Please check the plot. A-K - A-K2 are D9V. 
So the pics 0-12mA

But zoomed is about 0.3mA all the diodes (from 0.28 to 0.33mA).

So I think anyway we can use all of them and just listen. It's a question of sound color.
Please correct me if I'm mistaken.

[Fernando]

thanks a lot Ivan!

When I find time, I'll build a circuit to measure diode Vf at 0.1, 1, 5 and 12 mA, so I can manually trace their curves;
I see that measuring only at 1mA tells too little about their response.
But, of course, the most important is to listen.

Also, I just bought one of your transistor testers, it will be a big help

[Fernando]

Ivan, why the 3 D9V (Д9В) plots are so different? Specially one of them.
Older and newer units? Totally random?

Tested D9J and D9V again. Just to note - ge diodes have the same deviation as transistors' hFE 
Please check the plot. A-K - A-K2 are D9V. 
So the pics 0-12mA

But zoomed is about 0.3mA all the diodes (from 0.28 to 0.33mA).

So I think anyway we can use all of them and just listen. It's a question of sound color.
Please correct me if I'm mistaken.

[diy-tubes]

All from  the same package. Germanium is not "stable" I suppose. Need comment from real specialists. 

[Fernando]

some more readings

I was able to read at 6mA as well as 1mA, so I have a better idea of their curve now, very interesting:

1N270   0.236V@1mA, 0.34V@6mA FAKE? - sold as BKC but suspicious reading. One thick black line (see below) - STEEP CURVE
1N270  0.265-275V@1mA, 0.58-0.62V@6mA - (ST) two black lines. - SMOOTH CURVE
1N270  0.30-32V@1mA, 0.79-1V@6mA  -  (Unknown brand) two black lines. - VERY SMOOTH CURVE
Д18      0.30-34V@1mA, 0.55-0.62V@6mA  -  (D18) - SMOOTH CURVE
Д9В      0.265-285V@1mA, 0.52-0.59V@6mA  -  (D9V) - SMOOTH CURVE
Д311    0.177-19V@1mA, 0.28-0.30V@6mA  -  (D311) - STEEP CURVE but smoother than OA7
OA7      0.23-24V@1mA, 0.33-0.34V@6mA (Valvo) - STEEP CURVE

I was very surprised of such a different readings from the 3 different types of 1N270 diodes (I tested many specimens of each type)
The type sold as "BKC" on the bay (showing a picture of a BKC bobbin and even having "BKC 1N270" printed on their body) match Ivan's plot for "1N270-Modern" (at least up to 6mA). They have one thick black line. FAKE ?
The other two 1N270 types had different Vf but with a more credible curve, both close to Ivan's plot for "1N270-NOS".

My D18, D9V and D311 specimens match Ivan's curve plots very well (up to 6mA at least).

[Giglawyer]

Good stuff here.  Thanks for posting.