My neighbor droped off a tube to me and asked if I could try and id it. To me it looks like a 12AX7 or 12AU7 but I know next to nothing about tubes. The only markings I can make out on it are YY3 and L6K do these help to identify the tube? It also has 7 prongs on it.

I`asked him to let me know the radio it was taken out of, becase I could then search for a schematic for him....he's hecking.

Thanks for your help in advance.

Scott

Sometimes you can blow yr breath on a tube to where it "fogs up" & read the type # etched on the glass. It may take doing that a few times, but I'll bet it's there.-Sandy G.

Is it tall with "X" shaped plates inside? "YY" is the Philips code for EZ90, US number - 6X4.

Philips codes are small, often faint, usually at the bottom of the glass. And often the only identifying mark left...

Thanks to Brent Jesse for this list... http://www.audiotubes.com/PhilipsCodeList.pdf

Is it tall with "X" shaped plates inside? "YY" is the Philips code for EZ90, US number - 6X4.

Philips codes are small, often faint, usually at the bottom of the glass. And often the only identifying mark left...

Thanks to Brent Jesse for this list... http://www.audiotubes.com/PhilipsCodeList.pdf

Yes, it has X shaped plates. I've been huffing on the sucker and can't seem to see the etchings.

Scott

Anyone ever try ultraviolet lights to visulize old marks?