help identify this tube.....

[Guest]

I have a couple 12ax7's that I'm trying to identify.

The glass envelop is very skinny. Skinnier than any other preamp tube I've seen. They are a long plate design and they are stamped with "12ax7" and "Yugoslavia" in large white letters. In very small gold letters it looks like maybe "AOA" and something else I can't read. They sound fairly bright and thin with lots of high end sizzle. Anyone know what these might be? I don't know if they are old stock, or something new. They came in a used 1973 Marshall SL I bought.

If necessary, I can try to post a picture.

Thanks,
Steve

[Dai H.]

sound like Eis

[sub]

I know only yugoslavian made tube --> Ei