[Niteshade]

I used to have a wonderful sounding, NEW matched quad of TungSol 5881's. 

They were in a modified Fisher 800C that sounded soooo sweet!  Today I noticed one of the tubes has no getter in it.  The other three have a heavy silver coating on the inside top. Double getters were used. I was thinking there must have been an air leak, but air leaks make the getter powdery white. 

Close observation shows a substance within the getter support (they're round & conical) that's gray, like a poor, crusty solder joint. Could it be they just didn't flash? I never noticed the clear tube top before. It looks possible that small fraction of it vaporized, but I am not entirely sure.

I'm thinking the tube might be OK since there is no white powder inside the envelope. What do you think? Anybody else use a 'getter-less' tube? 99.9% of the tubes I ever worked with had at least a smidgen of getter on the inside of the glass.

[JoshK]

I'd ask Jim McShane his opinion on this.  He has loads of experience with these tubes and being a tube dealer is used to which has certain issues and whatnot.

I have zero clue about this. I'd guess they were gassy tubes, but do you notice any grid current draw when you bias them up?

[Niteshade]

How can I get in contact with Jim? The receiver hasn't been turned on since the disappearing getter. The last time I used it, everything worked perfect. Unfortunately, I do not recall what the tube looked like then. It hasn't been used in about 5 months. The tubes have about 10 hours on them and were never abused. In fact, they all ran very cool and had excellent tone. There are no flaws in the visible part of the envelope and nothing is loose or rattling.

[Berndt]

http://pages.prodigy.net/jimmcshane/