On 01/10/17 23:09, David R Brooks so wittily quipped:
You might consider the 5831:
https://frank.pocnet.net/sheets/201/5/5831.pdf
No, I haven't used them, but the data sheet rates them for Class-B audio
use at 370kW per pair!!
You'll need a heater supply of 2100A per tube, & the rest in proportion.
I don't want to hear about your power bills, either :-)
let alone, the size of the output transformer