im buying off some tubes from a voodoo store... lots of NOS RCA and National tubes there from 12ax7 to 6L6 etc etc...
how do i identify bad tubes by looking at them[physical inspection]?
like defective ones that doesnt work?

smashed glass


[ wrong forum??? ]
Quote by tubab0y
Look at it this way- everyone rags on air guitar here because everyone can play guitar. If we were on a lawn mower forum, air guitar would be okay and they would ridicule air mowing.

if you're buying off of a respected store, you shouldn't have any problems.
Look for chipped glass and strange marks. I guess it's the only thing you can check.
Call me Wes.
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I'm no expert on tubes so I can't say much, but them them like you woudl check a light bulb I guess, And if you really want to be sure, then go ask if you can plug them in.
Im pretty sure you cant ask to "test" tubes by plugging them in in a store dude!^^
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Old fart here, god I remember the days of tube T.V.s. Well, people would troubleshoot their own t.v. tubes by bringing them to the local "Five and Dime" store, lol. There would be a test stand in front of the store. You'd stick your tube in the applicable socket, insert your dime, or whatever it took, and presto, it would tell you if that tube was good or bad. Natch, you could buy a new replacement tube inside the store. How cool is that? Too bad the same system is not in effect for guitar amp tubes....