>Y'know, this statement keeps popping up, supposed to happen
>apparently even when simply placed in TX, without any drive
Well, the 3-500Z isn't that much bigger plate construction than the 4-400.
In GG, with grid and screen grounded and 3600 on the plate, mine certainly glows
under zero signal conditions at about 300 watts dissipation.
The 4-250As are a bright red at 250 watts dissipation.
That's the advantage of external anode tubes - they don't worry you by glowing!
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