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question about tubes.......

post #1 of 4
1/3/11 at 3:55pm
Thread Starter 

just got some tubes i got off of ebay. dont know one thing about this stuff. background...... i have a little dot 1+ amp on the way so i ordered some tubes. tubes were listed as NOS new but what i was wondering is they have a burnt look on top of them. does this mean....... used, not good... what? have no way of checking them yet since the amp will not get here for 2/3 more weeks. please some info. thanks

 

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Edited by scott6ppc - 1/3/11 at 4:01pm
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post #2 of 4
1/3/11 at 4:13pm

Old tubes were usually pre-tested in the factory for quality control, and to burn off whatever gas was still inside (no vacuum was ever perfect.)  Then decades later most NOS sellers do it all again, so a burned look is perfectly normal and nothing to worry about.

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post #3 of 4
1/3/11 at 6:08pm
Thread Starter 

thank you

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post #4 of 4
1/3/11 at 6:42pm
That is just the getter flash.

Suggest you take a quick read through this:

http://www.vacuumtubes.net/How_Vacuum_Tubes_Work.htm

Nice intro to how tubes work.
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