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

You may have to commit to conversion therapy as you do want to enjoy the stuff.

Generally yes. There are manufacturers (some Quad and Revox pieces) that allow you to simply switch from 240V to 110V. In most instances you will need a step up transformer, they are not expensive. See my previous post on this subject.

However, some manufacturers, Krell and ML come to mind, specifically engineer their equipment to operate on either 60Hz or 50Hz. If you try to use 240V/50Hz equipment in the USA it simply will not work. I found out the hard way when I took a Krell HTS from the USA to France. In the end I had to pay Krell, not cheap, to convert the processor from 110V/60Hz to 220V/50Hz.

The other factor to be conscious of is equipment running on AC synchronous motors, for example turntables. If you run this equipment at the right voltage but wrong frequency it will rotate at the wrong speed.

Thank you for your help.

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

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.

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.