Dropping 280 volts of B+?

[Alexo]

Hi all,

I'm building a 100 watter with a pair of 6550's for a pal o' mine. To get 100W, I need a plate voltage around 560 and a screen voltage of 300. Screen current will vary from 1.5ma per to 15ma, depending on how hard the amp is working. This means that the 100K dropping resistor I'd need at idle will reduce the screen voltage by an obscene amount once the screens start pulling some current. But if I use a big enough filter cap for the screen supply, is this even an issue?

I'm planning on using a series of 8 5 watt 33 volt zeners to get the desired voltage without this silliness, but this in itself seems silly. I've considered a separate PT, but that adds cost and takes up space.

Any ideas for a better way here? Is there something obvious that I'm missing?

...I know 8 33 volt zeners is ridiculous, but I can only find 5 watt zeners!