110 (or 120) vs 220

Ok. If the amp isn't designed to do both with no modifications from me then I don't want to do this. (I have a call in to the manufacturer).

I have a CPAP machine and it will automatically switch from 110 to 220 it I switch the power cord. Guess it isn't so simple for an amp!

For the interconnects, I was referring to a converter that you plug into the wall and then you plug the ancillary equipment into it. The converter takes 220 volts from the wall and converts to 110 for the equipment to use.

My reason for doing this is that my tube amp is rated at 35 watts / channel. I'm buying new speakers after having my Paradigm 5se's for over two decades.

I naively thought if I doubled the voltage I could ~double my available power (~quadruple at 4 ohms?) and that would vastly increase the pool of speakers I could choose from (e.g., Totem, Magnapan).

Never ran across no 2 pole breakers feeding audio equip in NEC.
Only advantage would be 1/2 current so you could use small gauge wire.

Also Audio equipment doesn't draw that much current to warrant 220v