I don't understand why the amp isn't fitted with a Commmando-type inlet like Boulder fits to their big power amps:
View attachment 395821
I don't know how common this type of connector is across the pond, but here in the UK, they're known as BS4343/IEC 60309 plugs and sockets. Yellow for 110 V centre-tapped isolation supplies for power tools etc., blue for 240 V single phase and red for 415 V 3-phase.
Single phase is available in 16 and 32 Amp ratings, 3-phase is available in 16, 32, 64, and 125 Amp ratings.