Rod Pentode TRF

[Kalee20]

But I don't think a nuclear blast generates the same sort of EM pulse as a coil with a burst of current through - so failing this latter test (which Amie has shown it would) doesn't necessarily mean the valves will die in a nuclear blast. I tend to think (very basic reasoning, as outlined previously) that they'd survive.

Your filament supply being regulated - so is mine! I have nevertheless seen a slight drift over some seconds, nothing which alarms me though.