24 Jul
2005
24 Jul
'05
10:11 a.m.
The minis and subminis of the 1950s, made for computer
usage,
were really not effected by power cycling. Filament burnouts on these
types of tubes are exceeding rare.
But inter-element shorts and leakage become more common, and my
experience (backed up by many years of leaky/shorted tubes) is that
these are related to power-on cycles. (i.e. "it worked last time I
used it, but then I turned it on and all it does is hum").
Maybe reduced sizes make physical tolerances between the elements more
critical in the smaller tubes. Even though a lot of the leakage
I've seen is between adjacent pins, not between adjacent elements.
Tim.