If a tube has leakage to air, it is doomed anyhow, and storing it in a
vacuum can only delay the inevitable. Leakage will start right in
again when the tube is put into service.
73 from Ian GM3SEK
----- Original Message -----
From: "David Kirkby"
To:
Cc:
Sent:Wed, 3 Oct 2012 16:17:59 +0100
Subject:Re: [Amps] preserving tubes
On 3 October 2012 06:20, Gary Smith wrote:
>
> Is there any benefit to taking a ceramic tube on the shelf and
> running it every so often and then returning it to the shelf to
> archive it for a backup when needed? Or os it just as well to let
it
> sit until needed?
>
> Gary
> KA1J
I have heard it is worth at least running the heaters up, but I
don't
know. This is the sort of information Reid Brandon at Eimac could
have
provided!
I've often wondered if it is worth storing them in a vacuum - or as
close to a vacuum as one can reasonably get. There's going to be
less
diffusion of gases into the tube if the pressure outside is very
low.
If you stored them at a pressure of 10% of atmospheric (VERY easy to
achieve), then would it reduce the diffusion by a factor of 10?
As you try to get to lower and lower pressures, the difficulty
increases. I don't think you would need to go to the effort of
things
like diffusion pumps.
I'll lot you lot think (argue) about that one!
Dave, G8WRB.
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