Using 110 V gear in 220 V countries

Could anyone advice What is the best power conditioner that can convert from 220 V to 110 V and has audiophile quality. There is no need to change the frequency (I have Audio Research - it works 50/60 Hz). Now I am using PS Audio 500, but it heats a lot and I am not sure that it will work long time.
Why don't you just get a nice step-up transformer and leave it at that? Or see about having AR change the power transformer wires. The power transformer should work on both 220 and 110 if they are using universal transformers.