Mike Andrews wrote:
Chuck Harris wrote:


Today it is trivial to make a simple switching power supply that can provide
a couple of hundred volts at 98% efficiency, why not make one of them, and
use some real tubes?


The problem I've encountered with switching supplies is that they're so
blasted noisy because of the fast risetimes in the high-current parts
of the supplies and because they're usually not very well shielded and/
or decoupled.

If you make it yourself, you can apply proper shielding and decoupling techniques.
It is done all the time in commercial radios. For a small receiver like is
being discussed here, the supply can be made in a couple of cubic inches...
Something that can be easily made in a soldered shut can with feedthru's on
all of the leads.

-Chuck