Is it really germanium ? - Page 1
Forum section: electronics / beginners

author: Jan Audio
author_rank: Frequent Contributor
timestamp: January 26, 2020, 04:40:13 pm
content: Hi, i have "germanium" diodes from china.How can you know if it is really germanium ?

author: BravoV
author_rank: Super Contributor
timestamp: January 26, 2020, 04:41:43 pm
content: Test the forward voltage, should be about 0.2 to 0.3 volt, compared to silicon is about 0.6 to 0.7 volt.

author: bd139
author_rank: Super Contributor
timestamp: January 26, 2020, 04:49:23 pm
content: Difficult to tell. I suspect many are schottky diodes.If you look a the low part of the V-I curve you can see the difference:Really you need a curve tracer but you can work it out manually with a variable bench supply, a 10K resistor and two DMMsI've got some Tayda "1N34A" diodes here. I will plot them vs genuine ST 1N5711 at some point.

author: schmitt trigger
author_rank: Super Contributor
timestamp: January 26, 2020, 04:50:01 pm
content: What part number?If you have access to a micro ammeter, you should be able to measure its leakage current.

author: tkamiya
author_rank: Super Contributor
timestamp: January 26, 2020, 06:08:07 pm
content: The real IN34A was a point contact diode. I could literally see with naked eyes, thin wire in the glass envelope making contact to a tiny silicone wafer.What I've seen on eBay a lot is nothing like that. Looks like generic silicone diode to me.

author: bd139
author_rank: Super Contributor
timestamp: January 26, 2020, 06:23:09 pm
content: You can get point contact ones still. The ones masquerading as 1n34a units may be 1n270 which are still produced.

author: exe
author_rank: Unknown
timestamp: January 26, 2020, 07:49:15 pm
content: I have them too. Also other forum members. I'm too busy to do a research on them. The only thing I measured was forward voltage, and it was surprisingly low (as displayed by my dmm). If I find them, I'll measure forward voltage under a few currents...UP: it seems I lost them or threw away. Still curious to see their VA plot.

author: Jwillis
author_rank: Super Contributor
timestamp: January 27, 2020, 08:11:08 am
content: Germanium diodes will have a much higher reverse current than a Schottky diodes.You don't have to get the crystal radio he's using here to check. Just put a small reverse voltage across the diode and check with an amp meter to see the leakage current.

author: Jan Audio
author_rank: Frequent Contributor
timestamp: January 27, 2020, 02:46:00 pm
content: Quote from: bd139 on January 26, 2020, 04:49:23 pmThanks, indeed i got those transparant ones.I also have some original blue ones somewhere, dont know the number.

author: Jan Audio
author_rank: Frequent Contributor
timestamp: January 27, 2020, 02:46:57 pm
content: Quote from: Jwillis on January 27, 2020, 08:11:08 amThanks i will try putting 5 volt on the black side, and measure on the other side ?edit : watching the movie nowThe movie says they are fake.Need to find my blue ones.

author: Jan Audio
author_rank: Frequent Contributor
timestamp: January 27, 2020, 03:25:35 pm
content: What is this then :https://www.ebay.com/itm/OA1160-TUNGSRAM-LOT-OF-10-GERMANIUM-DIODE-15V-5mA-GLASS-CASE-DO-7-OA160/283683557377?hash=item420cdb9001:g:0lYAAOSwJ8ldleG2Less packets available then viewers on this page.

author: bd139
author_rank: Super Contributor
timestamp: January 27, 2020, 03:43:25 pm
content: Ooooh a whole 15V before they blow up. Grab 1N270. Dirt cheap. Work just the same. Considerably less fragile than 1N34A and all the other ones.

author: Gyro
author_rank: Super Contributor
timestamp: January 27, 2020, 04:43:42 pm
content: Quote from: Jan Audio on January 27, 2020, 03:25:35 pmI've found it pretty unusual to get fake stuff from Bulgaria. It's usually NOS / ex military warehouse stuff.(Often fun stuff to be found).

author: Jan Audio
author_rank: Frequent Contributor
timestamp: January 27, 2020, 05:31:24 pm
content: How about russian diodes ?The last hour i found a lot on ebay.So much choice.I bet they all real those russian ones.

author: Gyro
author_rank: Super Contributor
timestamp: January 27, 2020, 05:37:22 pm
content: Yes, much the same, lots of warehouses full of goodies. Particularly RF Stuff, valves/tubes, hermetic caps etc. The only problem is that prices have gone up over the years as word got around.

author: SeanB
author_rank: Super Contributor
timestamp: January 27, 2020, 05:52:45 pm
content: Wonder what the green band point contact diodes i have are, must check out a few, after carefully removing them from the boards they are on.

author: Jan Audio
author_rank: Frequent Contributor
timestamp: February 22, 2020, 02:22:52 pm
content: I have 2 types russian germanium diodes in house now, waiting for the third type.

author: Jwillis
author_rank: Super Contributor
timestamp: February 23, 2020, 12:37:04 am
content: Quote from: SeanB on January 27, 2020, 05:52:45 pmGreen band is usually Schottky. Germanium have a red band. When it comes to vintage components it can get confusing .And where they were made the colour code can be different. Point contact can have a tungsten or phosphor bronze wire (Cat whisker). I have heard of gold but can't confirm that. The contact point can be either germanium or silicon.

author: Jan Audio
author_rank: Frequent Contributor
timestamp: February 25, 2020, 04:53:51 pm
content: I soldered the distortion the same and it sound much rounder lower and cleaner, less noisey.It has a different character, just soldered sounds vintage already.

author: Jan Audio
author_rank: Frequent Contributor
timestamp: March 19, 2020, 03:40:22 pm
content: I recommend this seller for germanium diodes, just arrived in the post :https://www.ebay.com/itm/200-x-D9K-GERMANIC-DIODE-30V-30mA-OTK-USSR-1-LOT-200-PCS/264594127116?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649Trusted seller, gave me 3 x 10 extra sorts.2 packages from 200 piece avaiable.

author: schmitt trigger
author_rank: Super Contributor
timestamp: March 19, 2020, 03:44:30 pm
content: JanAudio;please illustrate and educate me....what characteristic makes the germanium diode so desirable in guitar pedals?Thanks

author: Jan Audio
author_rank: Frequent Contributor
timestamp: March 19, 2020, 04:32:38 pm
content: You get a pure note.Not difficult to get a pure note in compate with a fake one from china "scottky diode".When you are slightly off with a fake you hear noise.

author: bsfeechannel
author_rank: Super Contributor
timestamp: March 19, 2020, 11:04:12 pm
content: Quote from: schmitt trigger on March 19, 2020, 03:44:30 pmDiodes are used in pedals for the non-linearities they introduce in solid-state amplifiers to mimic the non-linearities you find in tube amps.There are several designs employing all kinds of signal diodes. Some use silicon, others use germanium and even schottky diodes and LEDs. Each claim to add a specific sonic characteristic to the effect, based on each V-I curve.

author: Jan Audio
author_rank: Frequent Contributor
timestamp: March 20, 2020, 03:56:13 pm
content: I only use them in distortion btw.Quote from: bsfeechannel on March 19, 2020, 11:04:12 pmWhere in the schematic are they used ?, in the distortion in the amplifier ?I am searching for more applications since i have 570 germanium diodes in house at the moment ( 5 types ).Maybe it is a addiction : i know there are more out there that i dont have, while i dont need more.In a diode ladder filter ?, lets see.