Tube filiment voltage ???

[terry michaels]

Message text written by Magnus Danielson
>Of interest here is naturally the failure mechanisms of tubes, by what
mechanisms will tubes wear out, what accelerate/retardate these mechanisms
etc.
As being a novice to tubes at least I would love to hear about the
experience
that exist on this list on these issues.

Especially:

What failures do I get?
How does the wearing mechanisms work?
What can I do to reduce the failure probability?
How can I measure the condition of a tube?
<

The initial development of the vacuum tube for use as an audio amplifier
was done by the Bell Telephone company around 1913.  With extensive lab and
field testing of large numbers of tubes, and a great number of design
changes, the lifetime of telephone repeater tubes was around 70,000 hours
by the early '20s. They later developed vacuum tubes for intercontinental
submarine telephone cables that would operate more than 15 years without
failure.  The failure modes of these tubes, and the design changes done to
extend tube lifetime, are detailed in a number of textbook and periodical
sources.  I can try to put together a sourcelist if anyone is interested in
researching this further.

Terry Michaels