[Amps] Holding a vacuum

[Glen Zook via Amps]

It depends!  There are certain tubes, like the 3-500Z, that are notorious for losing vacuum.  But, I have quite a number of glass tubes that were manufactured in the 1920s that are still fine.
The ceramic tubes haven't been around as long as glass tubes.  But, those that I have, are still fine. Glen, K9STH

Website: http://k9sth.net
      From: Bill Turner <dezrat at outlook.com>
 To: Amps group <amps at contesting.com> 
 Sent: Wednesday, November 26, 2014 10:08 AM
 Subject: [Amps] Holding a vacuum
   
I'm curious as to your experiences with tubes in long term storage.
The question is, which type holds a vacuum better - glass or ceramic,
or is there no difference?

My own limited experience says ceramic is better, but that is only
with a few tubes. 

All comments welcome. 

73, Bill W6WRT
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