[Ian Iveson]

Ron wrote

Has anyone in the group found a switcher good enough for high
voltage (180 VDC), low current (.010 amps)
audio use. When I say good enough, I'm referring to noise and EMI.
I've been looking at LT, National and power integrations
but haven't found anything yet. I also need 12V @1.0 amp for
filaments.
Any ideas appreciated.

12V at several amps shouldn't be a problem.

You could then use an inverter and an LC filter for the HT.

A long way round, but available.

A purpose built, dual voltage, isolating switcher would take a bit of
development to get quiet, safe and reliable, and through a heap of
statutory approval procedures. Not a good bet for a market, either,
considering a valve amp is never going to be very efficient. It's not
surprising if you can't find one.

I imagined rewinding computer PS transformers might be a popular
entertainment, like hot-rodding microwaves or making jet engines from
turbochargers. Can't find any aficionados though.

cheers, Ian