Antonio Vernucci wrote:

I would not like to build a stabilized power supply, as that would be quite a
huge machine. Anyway I shall give a look to the diagram and see whether there
would be any simple way to feed just the oscillator tube with a separate
stabilized HV.

I know it seems like cheating.... but... consider a zener and TIP50 darlington.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."