Relationship of amplifier sound to transformer quality?

I should point out I'm not interested in redundant operation. I want increased power/current/va rating

Do you mean at the outputs of the amp/speaker connections? What value would be suitable?

No, the diode is in series to each +55V and -55V of the power supplies outputs to Amplifier. The reason of adding those diode in series is to isolate both power supplies and let each power supply only charging its own capacitor.
120V/30A diode is adequate.

I should point out I'm not interested in redundant operation. I want increased power/current/va rating

Since one power supply can provide enough power, parallel two power supply will definitely increase output current capacity and also can serve the function of redundant operation.

a] a quality output transformer is the heart of any good tube amplifier.b] do not try to combine the outputs of two separate transformers (AC power nor audio output). they will both be unhappy to say the least.c] do not try to combine the outputs of two separate AC or DC supplies. They will be more than unhappy.

@speedskatere,this is for ss psu.

@imhififan...So in this configuration, would it be beneficial to increase C to 20,000uf total for each psu, total 40,000uf per pair of psu? Or keep each psu at 13,600? TIA

would it be beneficial to increase C to 20,000uf total for each psu, total 40,000uf per pair of psu?

Yes, check dimensions if the capacitors can fit in before ordering.