What is the deal with those 1n34a diodes that look like silicon diodes?

[Rob Strand]

Thanks for the discussion. I'm building a couple of EQD Life pedals, I'm using the Parentheses Fuzz PCB:

https://www.pedalpcb.com/docs/Parentheses.pdf

It uses 4 or Ge diodes. The first half of the circuit is a Green Ringer. The two diodes here are listed as Ge but I'm pretty sure I can sub something else and it should sound the same.

The second section is sort of a Rat clone with a switchable diode clipping options. One option is a pair of Ge diodes. From the discussion here the take away suggests the imitations won't sound the same.

All that aside the Ge clipping option is my least favorite choice it's a lot quieter. I feel like I should experiment with a few diodes I have on hand and see what sounds good there.

The two diodes D1 & D2 in the rectifier/doubler  could easily be substituted with Schottky's.

As for the clipper, the level drop is common.  The way around it is to use two Ge's in series in each direction, so four diodes.   If you aren't sold on the germanium, try Schottkys instead.  Try using the 2x2 trick on the Schottky's so you don't lose level.   Some other options are  a series 1N4148+Schottky in each direction, or try power diodes like 1N4007's.   If you want something else try just a resistor, trim the resistor value to match the level against the other diodes then maybe add a cap in parallel with that to tame the highs.

[soggybag]

Thanks Rob those are some good ideas.

I found some 1n60p diodes in my parts bin. These have a larger body opaque blue with a black stripe. I wonder if these are Ge or more "Ge" work alikes?

[Rob Strand]

I found some 1n60p diodes in my parts bin. These have a larger body opaque blue with a black stripe. I wonder if these are Ge or more "Ge" work alikes?

If you can't see the wiggly wire it's pot luck.  Off hand I think the 1N60/1N60P was the diode with Schottky in some datasheets and "Germanium" in others.  It's really confusing.

You could try measuring the diode voltage at 10mA.

Just try them out, even if they do turn out to be Schottky at least you know you have tried the Schottky's.

[antonis]

You could try measuring the diode voltage at 10mA.

Believe it or not Rob, I tested 25 1N60 diodes (the last ones on the same strip bought from a local store ) and got from 270mV up to 460mV forward voltage drop..

To be honest, I didn't care about their actuall voltage drop - just wanted to much a pair of them for a Fender Blender clone..

[Rob Strand]

You could try measuring the diode voltage at 10mA.

Believe it or not Rob, I tested 25 1N60 diodes (the last ones on the same strip bought from a local store ) and got from 270mV up to 460mV forward voltage drop..

To be honest, I didn't care about their actuall voltage drop - just wanted to much a pair of them for a Fender Blender clone..

Those voltages certainly look more like Schottky's than germanium.

These voltages are from some of the older posts.  The 1N60 was from an old "real" germanium datasheet.

Two real germaniums and a BAT46 Schottky

I [A]   Vge(grn1) Vge(blk2) VBAT46
10m   1.25V          0.91V          0.40V

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.)

[Steben]

https://therepaircafe.wordpress.com/2020/07/14/emulating-germanium-diodes/

But as I don't have the gear for that I quietly assume that you can easily donate your germanium diodes to the nearest museum or you know, resell them with an even bigger profit margin to some audiophool who's so obsessed by the germanium placebo that they're willing to pay a good price.

[Steben]

https://therepaircafe.wordpress.com/2019/10/24/forward-voltage-of-various-diodes/

[Gert]

I've recently posted a reply to a closely related topic, "1N34A diodes. Cheap vs expensive."

– https://www.diystompboxes.com/smfforum/index.php?topic=126386.0

In this reply (Reply #54), I firstly addressed the three different types of germanium diodes that have to be carefully distinguished in this context:

– Germanium junction diodes
– Germanium point-contact diodes of the welded contact type
– Germanium point-contact diodes of the non-welded contact type

From the preceding discussions, it seems that the third type ought to be of primary interest here as well. Therefore, my proposed simple measurement method to safely distinguish these germanium diodes from silicon junction and Schottky barrier diodes and also from other types of germanium diodes will probably be of interest to readers of this thread, too.

[pinkjimiphoton]

I'm seeing lots of diodes listed as 1n34a but they look like typical 1n914 or similar diodes? Are these really germanium, or are they silicon work alikes, or just bogus?

ya get what ya pay for. them chinese 1n34's are not 1n34's, shit, if you're LUCKY they'll be 3v schotkes.

i went on a buying spree a few months back to re-stock ge diodes when i realized i was out of them.
i found like, maybe 3 sources for legit ones, sorry, not saying where, cuz every time i post info like that some ass will buy out the whole damn stock and then there's not enough for anybody else which is totally not cool.

most of the glass ones are si, not ge. sadly, the only way to really tell is to test the diode, if it reads above about a third of a volt, its silicon. that said, they're selling 1n60 schotkes now as ge, they react similarly, same voltage drop etc, but they're not ge.

about the only thing you can do these days is buy a bunch from a bunch of vendors, and then test them. if they come up as legit, go back and buy a batch.

i tried the chinese ones. i ordered a bag of 50. none were ge, all were silicon, and about 30 of them were just plain garbage.

off topic, but the chinese ge transistors are crap too, so don't waste your time with them. i ordered a batch of 20 to check 'em out and got ONE decent transistor, and a bunch of crap i can't even use as diodes.

hate to say it, but i'd ride til smallbear is back, at least with them, it was legit components.
surplus electronics sites are selling silicon as ge. beware.

[amptramp]

I have a box of germanium diodes from before the time they started faking them but there is only one problem with these diodes - there is no cathode band!  However, the diode outline is the old fat-bodied glass diode like the original 1N34 and the metal contact going into one side is a bit larger diameter than the other side.  The forward voltage is in the 0.325 to 0.335 region and the glass body is black glass (no doubt to avoid leakage current from light).  The larger diameter contact appears to be the cathode most of the time and there are about 100 of them in the box but I thought some of them had the anode as the larger diameter contact.  I used two meters so I could use one meter to tell which direction was positive in the diode test setting then used the other to measure a number of them.

So I now have a lifetime supply of germanium diodes but I have to measure them before I put them in a circuit to make sure what direction they conduct current.

I also have a small bag of other diodes that look like silicon and have a forward voltage of 0.573 in the small glass case, again with no cathode marking.  But I am not going into series production with either type of diode, so I can live with having to measure each one before I use it.

[soggybag]

This conversation is making it sound like those fake 1n34 type diodes, I'm thinking of the ones that look like 1n914 but little smaller, could be used in places call for Ge diodes in some cases. Would that be correct?

[iainpunk]

Never experienced a genuine Ge diode with a forward voltage drop lower than 450mV or so..

i have. my test Uf setup is trimmed to 10mA, and i have genuine old/salvaged OA31's from a huge old radio, they measured between 70mV and 100mV. and some other old unmarked ones measuring close to 220 to 230 mv.

a good way of finding out if a diode is Ge or schottky is reverse leakage. Schottky diodes leak multiple orders of magnitude less than Ge diodes.

cheers

[Phend]

Measuring included, if they don't look like this then ??
(You ain't got Mojo)

[Rob Strand]

i have. my test Uf setup is trimmed to 10mA, and i have genuine old/salvaged OA31's from a huge old radio, they measured between 70mV and 100mV. and some other old unmarked ones measuring close to 220 to 230 mv.

The low voltage ones won't be the common germanium signal diodes we generally use they will be germanium power diodes (usually quite old and in different packages).

[Phend]

If it looks like chicken it probably is chicken.
We ordered chicken on a stick at the local Chinese restaurant.
The texture and fish like big parallel flakes reminded me of carp.
Did not eat that. So check your diodes before using.

This is real chicken


This is sold as chicken , Chinese style

[PRR]

Our "Asian food" place, the Chicken Teriyaki always tasted/felt like pork.

[pinkjimiphoton]

Our "Asian food" place, the Chicken Teriyaki always tasted/felt like pork.

kittycat is quite versatile in that way i guess. i know it's a cliche, but years ago in my hometown, it led to the demise of a very popular chinese restaurant.

the staff said it was for their consumption only. either way.

tastes kinda like.... mystery meat.

[CheapPedalCollector]

I bought some 1n270 from a supposed reputable seller lately, they are completely fake and measuring .5 and up rather than around .23... very annoying.

[FSFX]

If you can't see a whisker through the glass envelope then it is not a germanium point contact diode like the 1N34A or 1N60.
Well that is unless it is one of the real original Sylvania ceramic tube 1N34 diodes in which case you have a museum piece.
Some manufacturers seem to have produced a Schottky diode and called it a 1N60P so that is silicon, not germanium.
There are, of course, some silicon point contact diodes like the 1N23 but those are usually in metal tubular or ceramic bullet envelopes and pre-date the germanium point contact diodes as they were used as detectors in WWII radar receivers.

A simple one point Vf value doesn't really tell you much unless you measure it over a whole range of voltages and currents like with a curve tracer and measure forward and reverse current at a range of different temperatures to see the thermal characteristics of the diode.

[Steben]

Our "Asian food" place, the Chicken Teriyaki always tasted/felt like pork.

Yes, Pork cuisine.
Just as Indian always tastes like curry (to me). No use in ordering non veggie.