> What is the general consensus for the best storage strategy for preserving
> the life of the spares?
The best advice I have heard from one tube mfr, and follow at work, is
to not store tubes out in containers or storage units where temperature
extremes will be present. With tubes worth $30K-$300K each, I follow
this advice. Only are duds put to pasture in storage units. Or display
tubes.
> If this is correct, are we talking about limited shelf life of unused
> spares? Or is this just BS?
Generally no, unless a particularly awful manufacture. I wouldn't know
how to determine this.
> Some stuff I have read suggested that leaving them sealed up in a box
This would, of course, protect them from rolling off a shelf, that's
all. Never set a tube on a hard surface with a jolt, esp after it has
lots of hours on the filament, as the thoriated tungsten in direct
heated cathode tubes will be more brittle with age.
> Should I just leave them in the closet, or should they be exercised
> periodically
If you want to nearly 100% guarantee they work, you might want to
exercise them, just to activate gettering. However, you reactivate it
when you light them up for usage, and that's why its wise to turn them
on for `15-30 minutes or so before HV, the longer time for larger tubes.
esp if they have been off for years.
But good tube manufacture won't be leaky so really don't need to do this
unless you have the time, and want absolutely to insure reliability.
However, just unpacking and inserting them, turning them on, and off
again, is another risk to lifetime. So go figure....
> Position in storage make any diff? Vert/horiz ??
Not really, as long as you don't jolt them (as mentioned before). There
shouldn't
be any sagging mechanism to the metallic elements of a tube when they
are cold and sitting there, at least within our limited lifetimes!
> Are there any differences between these things for external anode vs.
> traditional glass bottles?
External anode are said to have higher integrity seals. At least they
are mechanically a lot more solid than kovar/glass.
73
K5PRO
John
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