[BILL]

Use diodes! They are CHEEP and easy to build a full wave rectifier . The 0Z4 will replace a 6X5, they both use the same socket, only the 0Z4 has no heater, and is really not all that reliable either!
I take the original 0Z4 tube can apart an install the diodes inside the can, looks 100% original !Works so well I give a Life time guarantee on my 0Z4 replacement.
I restore auto radios for a vintage Chevy/GMC truck parts supplier.