Tubes in Blue


Some of the tubes on my machine show blue florescent neon color on their envelopes. Is there anything wrong with those tubes? Please provide your suggestion(s) and experience.

Thanks in advance.

Otto
yu11375
Normal color, don't worry about it. Subject has been discussed in detail on http://www.audioasylum.com/scripts/search.pl
Tesla offers premium E 34L tubes in both blue and red tinted glass.

No performance gain or loss, simply a way to add color to the amp. Think of your tubes as having the premium color option, but without the premium price :~).
Normal for some tubes to do this.What I can gather from some tube experts is it has to do with slow leakage of vacume gasses.Go figure.