The 4CX15000 takes a special socket and chimney to cool it and a 160amp
filament transformer, I think you should look into flange mounted
triodes that don't need a special socket and stay away from the 4CX's
that need a screen voltage. The triodes are tougher. The YC-156 is a
popular tube that bolts right to a plate, cheap as medical pulls for
scan units and if you want to go to 15000 look at the 3CX15000B7 , the
A7 requires the high dollar socket the B7 does not and is easy to mount.
Rich , also a ham kd0zz.