Eurozone sickness and 230v single phase vs 240v two-phase.

That is a Jea48 question.

B

Now, I’m cheap but I can afford an electrician. So the question that follows is whether audio equipment cares about the difference between 230v single phase vs 240v two-phase. And if so, what’s the best way to make 230 single phase from 120 or 240 American power?

A transformer is one option.
And one can get 120v to 230v transformer.

Much of the Eu stuff is double insulated, like their tools.
For those, you can use 2 phase or single phase and the gear has no idea.
One just needs a US 220v male plug, and the Euro plug on the other end - e.g. for power tools.

But I would suggest that you ask the manufacturer of the ones you are most interested in… The majority of Europeans seem to speak english and/or 3 or more languages.

European 230 volts is from hot to neutral (or grounded).

USA 240 volts has no neutral, it’s 120 volts for each leg. (120 volts is derived from grounding each leg).

If a European 230V transformer is wired to the grounded conductor, it’s a non-convertible and you can’t use it in a 240 volt US outlet. If the 230V transformer has two 115 volt primaries that can be configured to be commonly grounded in series or parallel, then it can run on either 240V or 120V. This is done by the user with jumpers or switching. You will have to up the fuse size if it can do 120V.

Note that the extra ten volts may or may not be a problem. If the secondary side of the power supply (DC voltage) capacitors are rated very close to that secondary DC voltage, the extra 10 volts will be a problem as it will raise the DC voltage by 14 volts. The 60 hz frequency should not be an issue with 50 hz amplifiers.

Technically, US 240V is 1 phase, but balanced. Appliances that use balanced power, like your dryer or range, should use double pole power switches and breakers which disconnect both legs of power at the same time.

Most modern equipment intended for 120V expects an unbalanced input, with only 1 fuse and only turns off 1 leg.