[Milsurplus] How Much Vacuum in "Vacuum Tubes?"

[Bob Camp]

Hi

A lot depends on the tube and it's intended application. Some things  
like magnatrons will run just fine with a pretty poor vacuum. A high  
voltage rectifier probably won't be as tolerant.

Typical factory numbers probably were in the 10-8 to 10-10 torr  
region when they pinched them off. Oil pumps with cold traps were the  
common way to do the job in most plants.

Bob


On Mar 28, 2007, at 3:01 PM, David Stinson wrote:

> "Vacuum" is a relative term.
> Just how much "vacuum" does one need to make a vacuum tube work?
> Our valves can't be at perfect vacuum; no way that thin glass
> would hold up.  So is it possible for an amatuer to create a
> vacuum pump and chamber good enough for tubes?
> Kinda thinking about how to recover rare or expensive
> tubes that have gone gassy or low-em.
> I have engraved-base, big-globe types 80 and 50
> that would look soooo good in a classic '20s homebrew,
> if only.....
>
>
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