Are these tubes any good?

[sidecarjoeg]

I realize you can't tell by looking at a tube if it works or not, BUT... I was going through my attic because we're moving and found a bin with a few tubes. I have what looks to be like 4 12AX7A's (3 RCA and 1 Telefunkin) and 2 12AU7A's (both RCA). There are also 2 oddballs - 6AU6A and 6CG7. Is there any way to tell the age on these? I don't see anything resembling a date code or anything. Are there any remotely moderns uses for the other 2? All the tubes look like they're about the same age.

 

[ranjam]

The 6AU6 is a Pentode and the 6CG7 is actually a dual-triode like the 12AX7, but there is no center tap for the filament, so you can only run it 6.3VAC and pin #9 has to be left open. I'd keep that one. Keep them all, and find anyone with a tube tester. Maybe your local music store, especially if they sell tubes. Maybe the local old guy who fixes radios. Someone will have a tube tester. Try the local audiophool. The 'better' the tester, the more believable the test results.