OA128 diodes

[nieradka]

Are these germanium or silicon? Ive seen differing descriptions online. Has anyone use them and if so, how do they sound, say in comparison with a oa126?

[soldersqueeze]

Are you asking because you saw them on Chromesphere's new site? I checked them out for the same reason, and they're certainly silicon. Hard to find much more than that- maybe Paul will chip in with some real experience with the things.
I can highly recommend trying out the OA126's he sells. Germanium sound with silicon volume makes for a tasty clipping section, perfect for giving any overdrive pedal some hairier balls.

[alanp]

Yer mean bourbon's not enuff?

[chromesphere]

Hey guys, ill have to check the FV when i get home, but im pretty sure the oa128 is around 0.7v, approx double that of the OA126.  This would definitely put them in the realm of silicon.  Pretty sure the oa126 is silicon as well?  I'm not 100% on those details but i can check them out tonight when i get home if you like?
Paul

[midwayfair]

Hey guys, ill have to check the FV when i get home, but im pretty sure the oa128 is around 0.7v, approx double that of the OA126.  This would definitely put them in the realm of silicon.  Pretty sure the oa126 is silicon as well?  I'm not 100% on those details but i can check them out tonight when i get home if you like?
Paul

Here's a datasheet with a list of all the OA diodes in one place:
http://www.datasheetarchive.com/OA128-datasheet.html

OA128 is silicon. OA126 is a Z (zener) diode, but it "passes" the heat test (Fv rises with finger heat, and it has pretty severe reverse leakage when it's warm), I've seen them listed as germanium in more than one place, and they sure as hell sound different from zener diodes I know are silicon. The lower wattage could also be a clue (I've seen other germanium zener diodes and they're always 1/4 watt Both clip around 0.6-0.7v. I don't know the reverse voltage on the OA126.

OA is *supposed* to be the continental designation for germanium. The silicon diodes are usually BA, and zener ZA. There's a handful of outliers on the OA series, and I have no idea why that is.

[nieradka]

Ok thanks for the info, I was confused, as well its confusing. I love the sound of the oa126s in alot of circuits, was looking similar options, maybe ill start watching ebay for other germanium zeners.

[midwayfair]

germanium zeners.

They're usually kind of expensive, unfortanately.

Don't forget you can just stick two germaniums in series to get the Ge sound at silicon pric ... er, I mean, silicon Fv. The OA126 was convenient for sure, but it's not the only way to make something sound like that.

[nieradka]

Oh I know, I just often like the sound of the oa126s, and its is convient. And i have an itching to buy another pile of dubious diodes from eastern europe. I have an addiction to having a salad of weird diodes available when it comes to do the clipping section of a pedal, and was thinking of what to add to my options. 

[chromesphere]

Hey guys,
Finally got a chance to test the FV drop for these. I've added them to the store listing. (They were both around 0.65v):

OA126:
http://www.diyguitarpedals.com.au/shop/index.php?main_page=product_info&cPath=2&products_id=10

OA128:
http://www.diyguitarpedals.com.au/shop/index.php?main_page=product_info&cPath=2&products_id=14

Paul