IN34A spec
- Thread starter makisushi
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PedalBuilder
Well-known member
Both of those look like fakes. Real germanium diodes look like this:
The ones in your pictures look like Schottky diodes.
The ones in your pictures look like Schottky diodes.
PedalBuilder
Well-known member
What did you plan on building with them? For lots of circuits (Klon, Distortion+, Super Fuzz, etc.), schottky diodes make excellent substitutes for germanium diodes.
yeah they don't even look like the sku number on the package: https://www.jameco.com/z/1N34A-Major-Brands-Diode-1N34A-General-Purpose-Germanium_2220533.html
hmmm, that's weird I also have some AA112 germanium from small bear electronic and they don't seem to be on spec either.
smallbear-electronics.mybigcommerce.com
AA112 NOS Germanium Diode 25v 40mA Thomson CSF
AA112 NOS Germanium Diode
smallbear-electronics.mybigcommerce.com
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falco_femoralis
Well-known member
From what I've read the 1n34a was a generic part number that referred to any number of Ge diodes, and then later on was repurposed/reassigned as a Schottky diode.
I bought some NOS ones from antique electronic supply (I think) but it's just not something I want to chase. I like the sound of cascading transistor overdrives more anyway.
I bought some NOS ones from antique electronic supply (I think) but it's just not something I want to chase. I like the sound of cascading transistor overdrives more anyway.
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I can hear a difference when changing transistors on something like a Fuzz Face, but I haven't used sockets for clipping diodes in my builds so far. One pedal in progress is the TG Music DOD 250 clone. I might use a socket in this one to try different clipping diodes. Does temperature in a germanium diode affect the tone as much as it does with transistors?
PedalBuilder
Well-known member
That diode looks like a germanium diode. The Vf figure that Small Bear lists is the Vf for that diode at a specific current and temperature. If you're measuring the diode at a higher current and/or a higher temperature than Small Bear, then the Vf that you measure will be higher.hmmm, that's weird I also have some AA112 germanium from small bear electronic and they don't seem to be on spec either.
AA112 NOS Germanium Diode 25v 40mA Thomson CSF
AA112 NOS Germanium Diode
PedalBuilder
Well-known member
It does somewhat. As the temperature gets hotter, the diode's Vf increases. So you get slightly less clipping and compression as the temperature goes up. It's not nearly as drastic a change as a fuzz face, where the temperature change shifts the bias of the entire circuit.
"These are NOS, in the standard DO-7 glass case. They have the part number printed on the body. Vf is in the .28-.29 range. 25v, 40mA. These are high quality parts in perfect condition."
My Vf is 774mV that's almost triple the .28 spec... I thought the voltage drop was constant in diode.
PedalBuilder
Well-known member
The 25v, 40mA spec is probably the maximum that the diode can handle, not the test specs. The .28-.29v that Small Bear measured was probably measured at 1mA, which is the test current for many multimeters. If your tester tests at 5mA, which is not unusual for testers like yours, then a Vf of .77v is well within spec, as is the .28-.29v at 1mA:
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BrainDrain
Active member
You probably already know this but pretty much any of the Russian D9 series diodes work great as replacements for a 1N34A. I use the D9K mostly. They’re cheap and readily available on eBay from sellers in Ukraine.
Thank you still have much to learn about electronic
PedalBuilder
Well-known member
The D9 series are all quite similar and are good substitutes for 1N34A as clipping diodes. The D2 series are similar to the D9 series and have a slightly higher Vf. The D18 has an even higher Vf and much lower reverse current leakage; I really like those as the diode in Tone Bender Mk. III/Buzzaround/Dizzytone type circuits. D310 and D312 have much lower Vf and a harder knee; I've used those in my Harmonic Percolator builds and they sound great. They'd probably also sound great in a Super Fuzz, as the lower Vf will make the octave sound more pronounced. Bear in mind that the D18, D310, and D312 come in a much larger package size, so it takes a little bit of creativity to get them to fit on the PedalPCB boards.
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