Tung Sol 6L6 Tube health - silver coating not same on tubes

slash57X

New member
Hi,

I got some used tubes when I got my last amp.

Do you think they're still usable?
The silver coating is a quite a bit gone on the outer tubes, is that a problem?

Thanks very much!

slash57
 

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The tubes are fine. They coat the walls of the tubes with barium. When the getters are fired, barium reacts with oxygen to create the silver colour that you see. Uneven distribution of the barium reaction with remaining oxygen inside the tube is not indicative of any malfunction unless the barium is a bright white color, which means the tube does not have a vacuum pulled and is therefore faulty.
 
Thank you very much! :)
Sorry for the late reply, sometimes I didn't get a notification, and the topic did not show up for a long time
 
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