[Amps] Filtering capacitor in a HV PS: How low can you

[Will Matney]

Angel,
Correct but don't forget filtering the control grid voltage too. It can 
cause IMD just as bad if not worse than the screen especially in grid 
driven tetrodes.

I am not sure about this. 4CX250Bs should be quite indifferent to HV
hum, if screen voltage is well regulated, so I would rather concentrate
on the latter. What do you think?

I will do that, right now.
Many tnx for your help
Angel Vilaseca HB9SLV