Can anyone tell what tube this is?

[petercintn]

I ordered a Crack but it will be awhile till it gets to me.  I bought a couple of tubes to roll in it when I get it built.  After I got home from having the doctor cut out an ingrown toenail (did I mention my toe hurts?) one of the tubes was waiting for me in the mail.  So i took a look at my new pretty and here's what I saw,

(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fimg196.imageshack.us%2Fimg196%2F6979%2F037ro.jpg&hash=304f852b025e8edbc7a78e6c36c924d07199a9ec)

(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fimg94.imageshack.us%2Fimg94%2F1047%2F038bkd.jpg&hash=e6fb63eae8fd5c865f953c5e8a6a5f7e440ff230)

(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fimg851.imageshack.us%2Fimg851%2F9974%2F041dk.jpg&hash=4e4fa579a4065e7171770263c9a51a52f093b891)

Not a marking on it.  I sure hope one of you fine folks can identfy or verify what this tube is.  It was listed as a RCA 6AS7G Black Plate, but I'm kinda leery about sticking this tube in... the amp.  ( I just couldn't bring myself to say it the other way!)   

Thanks

[jrihs]

the base is not tapered so not russian...Looks like all the RCA 6AS7G Black Plates i have seen though i do not currently have one to verify that. My Chatham JAN 6AS7G does not have lower skirt below the plates, so its not that (tung sol would probably be the same as the chatham i'm guessing)

[porcupunctis]

I just pulled my RCA 6AS7G out of my {headphone amp}.  I couldn't say it either.  The plates, spacers, everything I see in your picture looks exactly like mine.  The markings on my glass are just about worn to the point that they can't be read and the base markings are also worn pretty well.  I'm going to guess that yours has just worn off completely. 

One thing that seems a little different is the very bottom where the pins come out.  Mine has a clear rim where yours is smooth to the edges and mine has raised lettering that says "LICENSED ONLY TO THE EXTEND INDICATED ON CARTON" wrapped around the outside edge of the pins.  This could just be a different run, or year of mfg. or whether it was intended for military use or commercial use. 

[arveedub]

The painted label on tubes frequently wears off. Try putting the tube in the freezer for 10 minutes or so. When you take it out condensation will form on the glass & may reveal the old markings.

As an aside: Your tube is very likely a 6AS7G made by RCA. Odd that the base didn't have any markings.

[2wo]

I think you get the award for clever tube tip of the day...John

[petercintn]

I tried the freezer trick and behold!  I saw AS7 and below that a G but the rest of it is gone. Cool beans.

Thanks everyone and to arveedub especially, it was a clever tube tip!

[Grainger49]

The painted label on tubes frequently wears off. Try putting the tube in the freezer for 10 minutes or so. When you take it out condensation will form on the glass & may reveal the old markings. . . . 

That is clever!

[Laudanum]

That does look like an RCA.  Reagrding the base ... I could have sworn that, a while back,  I ran across a site that mentioned replacement vacuum tube bases.  I dont know if that is possible, or if Im thinking of something else.  But if Im not going senile here, maybe that would explain the lack of markings on the base of the tube.   I just did a brief search and came up empty so maybe it is just age creeping up.