I just connected an imported lowish cost step down conditioning transformer that takes my 240V (nominal, sometimes higher) supply and outputs to 230V and to 220V outputs.
This followed two boxes needing repair, supposedly due to overvoltge. I would otherwise have stayed with a 'normal' power conditioner. My components have 220 on the back of some, 230 on the others.
It's sounding good so far, but it's barely had time to warm up yet.