Source for true low forward voltage Germanium diodes?

[Focalized]

I've gotten very mixed results with Germanium diodes. I have some that have the green stripe on them, some with the black and some that look just like 1N914 silicon.

The ones with the lowest forward voltage are the last ones mentioned. I don't remember where they were from. The other two styles are pretty much just like silicons.

Looking to get a good bunch with the proper ratings. I see lots of vintage diodes from Russia and Germany but would only try some of those if I could find a decent amount of other things to buy from the same seller.

[Mustachio]

Hmm strange... I guess you will get some variation from component to component .

The black stripe ones I thought where usually 1n34a , and the green stripe ones where 1n270's. But I could be wrong , they may have changed over the years. Not sure about the ones that look like 1n914.

So from the sounds of it you have been testing their forward voltage and getting lots of variation ? For some reason I thought that was normal with germanium.

As for where to get em , I get mine from tayda and haven't noticed any problems with them.


http://www.taydaelectronics.com/diodes/germanium.html

[Focalized]

I've seen all three styles sold as 1N34A. So I don't really know what a real one is. I assumed the green stripe ones were 1N34A from when they were included and listed as in BYOC and GGG kits. But the sellers around now might use that label for other Germaniums. I've seen 1N60 and 1N270 often. Never sure what was what I was looking for.

Sometimes they list them as being different brands.

Technically I think that what I want is the lower range of forward voltage. For octave fuzzes and such. I
m not positive that's what I need for that kind of use for a diode. Only from casual research and experimentation.

[italianguy63]

(deleted)

MC

[Mustachio]

You know Focalized your right ! I remember getting 1n34a's with the green stripe . Maybe its the 1n270 has 2 stripes ? I can't remember off hand. Have you tried the ones from tayda ? I thought the leads seemed a lil weak but they work fine.

I have noticed some inconsistencies In my cheapo metal film resistors recently. Like way off the 1% or 2% they are supposed to be. So it might be a quality problem. Luckily I was bread boarding a green ringer that just didnt sound like it should. pulled a few resistors and put them on the fluke and they where way off. Double checked the stripes and it wasnt just a miss labeled bag.

Just curious which octave fuzz are you working on ? Cause I'm working on a foxx tone machine as we speak! haha 


I thought I read some things on geofex about this before but I can't find it maybe it was here on the forum I read it. But I did find a lil info here

http://www.geofex.com/effxfaq/distn101.htm

Scattered through the page is some info but if you scroll down to the bottom , circuit types , #12

Also this was interesting

http://www.geofex.com/Article_Folders/Screamer%20Octave/tsoctave.htm

[Focalized]

It was also a Foxx Tone Machine I put together. I started measuring the diodes when I found most of my germaniums with the green and black stripes measured the same as thr common silicons. Only the smaller ones I mentioned measured lower voltage. Look just like 1N914 without any writing on them. I just don't know where I got those.

[midwayfair]

Part numbers are manufactured by more than one company. You can't go by the color of a band to determine the part number. You need to know the other characteristics of the diode to determine what makes it any given part number. For our purposes in stompboxes, we mostly care about the forward voltage and nothing else.

If you want the lowest forward voltage possible, don't bother with germanium. Just get Schottky diodes. 1N60P and 1N5817/18/19 regularly have Fv near 0.2V, whereas germanium diodes will read closer to 0.25-0.35 V. If you are using them as rectifiers, you doubly want to avoid germanium because of its temperature instability. As the temperature rises, the forward voltage goes up. Rectifiers need to have predictable results.

In clipping diodes, it doesn't matter as much, and the knee of germanium is different, which can potentially add some interest to the sound between different diode types (this probably matters/is audible less and less the more complicated the circuit gets ... if it's even audible at all).

1N34A should clip near .35v. If yours deviate more than a half volt from that, they are either fake, defective, or another diode type. The ones that look like 1N914s? Those sound like you got them from Tayda, and they're ... 1N914. I seriously don't know why they were ever marked as germanium 1n34As, because they are clearly silicon, their Fv is that of a 1N914, and they look like the 1n914s that Tayda sells. If yours clip near .25V, they are most likely a Shottky work-alike.

If you have black stripe ones that clip all over the place, those sound like a lot of the modern production 1N34As I've tried coming out of China (both from Tayda and from Ebay). The quality control on them is just terrible; I've had batches of 10 all be good and batches of 10 all be bad. At this point, I just buy NOS diodes that I know are genuine from reputable sellers. It's just less to worry about, and the price isn't any higher.

How do you tell if your diode is germanium? The easiest way is to see if it reacts to temperature. Measure the forward voltage with your multimeter by hooking up the diode with alligator clips. now hold your finger to it. The Fv should rise. Silicon is far more stable under such low temperatures, so it won't react.

Diodes are unfortunately one part that it's tough to get a handle on from datasheets, and even worse the difference between your multimeter and mine might produce different forward voltage readings -- there is a Peak meter, I think, that somehow reads germanium as twice the forward voltage it should be. Fortunately, diodes are cheap, and you can build up quite a stash just getting a couple and measuring them yourself.

[Mark Hammer]

My experience is that you just have to measure them, and hand select.  Where the diodes are placed in series with the signal, one generally wants as low a Vf as you can get, so as to allow as much of the entire half wave through as possible, although sometimes the slight delay that a higher Vf can appear to produce can be attractive.

If one is dead set on as low a Vf as possible, consider Schottkys.  I can't imagine that their composition will have any effect on the tone apart from whatever a lower Vf does.

[PRR]

You know that all Germanium *transistors* have two Ge *diodes* in them??

I don't think transistors get as mis-marked as diodes do.

[Harry]

1N34A should clip near .35v. If yours deviate more than a half volt from that, they are either fake, defective, or another diode type. The ones that look like 1N914s? Those sound like you got them from Tayda, and they're ... 1N914. I seriously don't know why they were ever marked as germanium 1n34As, because they are clearly silicon, their Fv is that of a 1N914, and they look like the 1n914s that Tayda sells. If yours clip near .25V, they are most likely a Shottky work-alike.

If you have black stripe ones that clip all over the place, those sound like a lot of the modern production 1N34As I've tried coming out of China (both from Tayda and from Ebay). The quality control on them is just terrible; I've had batches of 10 all be good and batches of 10 all be bad. At this point, I just buy NOS diodes that I know are genuine from reputable sellers. It's just less to worry about, and the price isn't any higher.

How do you tell if your diode is germanium? The easiest way is to see if it reacts to temperature. Measure the forward voltage with your multimeter by hooking up the diode with alligator clips. now hold your finger to it. The Fv should rise. Silicon is far more stable under such low temperatures, so it won't react.

Diodes are unfortunately one part that it's tough to get a handle on from datasheets, and even worse the difference between your multimeter and mine might produce different forward voltage readings -- there is a Peak meter, I think, that somehow reads germanium as twice the forward voltage it should be. Fortunately, diodes are cheap, and you can build up quite a stash just getting a couple and measuring them yourself.

Interesting, thanks for this info. I just got my 10 "1n34's" from Tayda today so I decided to investigate as well. Double black bands all reading between .28-.31V. The Fv drops by about .005V when touched about the same reaction I got from measuring some 1n914s. The bat41s I received from Tayda measure slightly lower and are much more temperature stable than even the 1n914s I have. A\Bing the 1n34as against the bat41s in a clipping circuit and they sound nothing alike?

[Focalized]

Just to show the ones I have.

I'm out of the green striped ones. But they had the highest voltage of what I have. Up near 0.6v.

The top two read about the same. Around 0.36v to 0.4v. The black stripe ones were listed as 1N270 I think.

I bought some of the red stripe ones listed just as NOS Germanium.

The bottom one has the lowest voltage around 0.26v. The range that might be best for say an octavia maybe? I can see clearer, now in the pic they have 1N60 on them but look just like 1N914.

A google search of 1N60 comes up with pictures of all three in the picture plus the green stripe ones. I suppose sellers often just interchange some of these styles just calling them Germanium?

Also you see the "joint" the tiny ones came in labeled with 1N34A. Anyone recognize the packing? Can't remember where they came from.

[psychedelicfish]

If you only need a few diodes, look out for kid's electronic kits in garage sales, on freecycle etc. They quite often have Ge diodes for crystal radios in them.

Otherwise, as PRR hints at, you could get a whole bunch of low gain Ge transistors and use either the B-E or B-C junction as a diode. If your transistor is PNP, then the cathode will be your base, collector/emitter your anode, other way round for NPN.

[guitarkill]

I just got some 1N270s which are supposed to have a low forward voltage, but they all measured just about what my 1N34As did. Both types measure around 340-360mV  Guess I'm going to have to get some schottky types in order to get about 250mV for my orange squeezer build.

[duck_arse]

I have some yellow banded Ge diodes I can still make out "60" on, which makes it an "OA60", and therefore the green banded ones I have are "OA47". I've always had the black banded ones as "AA" something, like AA110.

whatever happened to all the OA diodes?

[midwayfair]

The bottom one has the lowest voltage around 0.26v. The range that might be best for say an octavia maybe? I can see clearer, now in the pic they have 1N60 on them but look just like 1N914.

A google search of 1N60 comes up with pictures of all three in the picture plus the green stripe ones. I suppose sellers often just interchange some of these styles just calling them Germanium?

Those are 1N60P, a Schottky (silicon) workalike for the germanium 1N60 diode.

You can't go by the visual appearance of a diode to tell what it is. And the part number will pretty much never matter. If it's marked, fine. If it isn't, figure out what the Fv is and if it's germanium, and move on.

duck_arse: OA was the continental designation for germanium diodes, with many having equivalents for the US numbering system. AA is for silicon. I imagine they went the way of the dodo at the same time as other germanium parts.

[Govmnt_Lacky]

I have a metric crap ton of 1N781A Germ diodes. Cant remember what the Fv is but, I remember sending some to LucifersTrip (maybe) and they sounded great!

[duck_arse]

http://pdf.datasheetcatalog.com/datasheets2/32/32423_1.pdf

silicon? this is the AA119 I was thinking of, and I forgot the OA90.

[midwayfair]

http://pdf.datasheetcatalog.com/datasheets2/32/32423_1.pdf

silicon? this is the AA119 I was thinking of, and I forgot the OA90.

I stand corrected! And I was wrong. The "A" before the number is what designates it as germanium, as opposed to "B" for silicon. I was wrong! http://en.wikipedia.org/wiki/Diode#Pro_Electron