19 Jan
2004
19 Jan
'04
5:27 p.m.
Tubes are still being manufactured, but 50 years from
now,
will they still be made?
Very few types are still being made. I do not think anyone is making
computer grade tubes - the DOD still has plenty left in the depots.
If not, how feasible would it be
to make a replacement for an existing tube (assume a common
tube where characteristics are known) as a hobbyist?
Quite easy. It has been done already for the old radio folks. There are
little wafers that slip right under a 201 (or WD11) that contains a FET
and contacts for the pins of the tube that pass thru the wafer. These
work quite well, so duds can be used quite well, and the look of the
radio is maintained (along with the filaments' light and heat).
Of course, FETrons were commercially available solid state tube
replacements from the 1960s and 70s - they can still be found, and come
in many models, emulating quite a few complex types. The disadvantage is
that the old tube must be removed, along with that glow.
William Donzelli
aw288(a)osfn.org