Many of the home brew circuits I've seen on this forum still use rectifier tubes for the B+ voltages. It would seem to me that this task would be better served by solid state rectifiers. The advantages: Much less heat, and one less tube to replace. The preamp and output stages wouldn't know, or care, how the rectification took place. Those little diodes would even be handy to make a dedicated -V fixed cathode bias circuit for the output tubes.