Two of those quad 6V6 amps are going to draw more than 320 mA each. That's a big transformer by most standards. I would call Heyboer Transformers in MI, and get a custom wound. Specify all the heater current you'll need and run with it. It depends on how you want to run the filter, as that will dictate the AC voltage. L-C will be ~340vac, and CLC or CRC would want more like 250vac. cheers, Douglas