If I buy electronics from England, will I need some sort of converter to use them here?

Ask. It depends on the gear and how it's wired.

In the case of linear power supplies, sometimes you are lucky and it's either a switch you can slide over on the back, or internal jumpers you can move. Usually this is a little slider near the AC socket.

In the case of switching power supplies, it's automatic. You'll see them say "110-240V" or something like that in the specs.

So anything you buy with a wall wart is totally portable, you will need to replace the wall wart (i.e. wall mounted power supply) either from the manufacturer, or find a generic replacement in the US.

Like that Arcam unit you mentioned, 12V 1.5 Amps, easy to find here, just have to get the right connector.

Sometimes the wall warts themselves are multi-region, and come with plug adapters. In any event, this should be a cheap fix.

Its wall wart is multi-region, and come with plug adapter.