Germanium diode

[micromusic]

Hi

Any one more knowledgeable than me know what to replace an OA95 with a modern equivalent, I can get some but would be easier if Rapid ,Farnell RS etc would have an alternative

Thanks

[blue hell]

It depends on what they are used for .. like in a distortion circuit you'd probably want to use Germanium as has a lowish voltage drop which kicks in slowly ... when softness is not needed, for the voltage you could use a Schottky type .. when the exact volltage is not interesting a silicon diode or even an LED.

The OA95 very much is a general purpose diode, so for types it could just be a general purpose thing too - provided the design constraints dont get in the way.

[Grumble]

also, not known to everybody: when the black paint is damaged or (partially gone) the diode get very sensitive to (changes of) light.

[AlanP]

There is ungodly amounts of variation in Ge diodes, even within the same production code. Same with Ge transistors.

If you're able to, socket the position and audition a few diodes. I've got a bagful of Russian D9D diodes I just use.

[sompost]

In the ASM-2 synth that I'm building, the designer suggests using a 1N34A as a substitute for the OA95.

But I'm just an ignoramus.

[Grumble]

I tend to disagree with your designer, ok, they are both Ge diodes, but the OA95 has a reverse current of max 10uA at 10volt while the 1N34A has a reverse current of max 30uA at 10volt.
Also the max reverse voltage of the OA95 is 90volt (peak repetitive 100volt), and of the 1N34A it is 20volt (peak repetitive 65volt).
Because that's what its all about in the world of synths:) the voltage drop of the OA95 is 1.05volt at 10mA according to the datasheet, while it is 1.0volt max at 5 mA for the 1N34A.
You might consider that equal
The modern datasheets all give nice voltage/current diagrams, but (maybe because the spread in data was to large) the old ones don't.

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[sompost]

I'd say it depends on the details of the circuit. In his suggestion "my designer" wrote: "Any germanium will work fine here" (magic word: "here"). So there appear to be situations where a 1N34A will do the trick if you can't get OA95s. In all honesty, I'm the not most qualified person to tell.

In any case, I believe you can still get OA95s at places like utsource.com or on ebay.

Ralph

[Grumble]

thats why i wrote:" i tend to..."

[AlanP]

How is it used? The BOM indicates it's in the VCO, but I can't find a schematic.

[Grumble]