There is a lot of stuff these days that is readily convertible. Those that are not are the odd ones out, and frankly the manufacturers ought to get with the program here. I have played around with isolation transformers and in general the effects were bad, akin to poor quality AC. Utterly hopeless on amps, bad on preamps and maybe acceptable on CDPs, if you can stand the ringing, and acceptable on transports/turntables. They are especially bad if you have invested in good AC in the first place. Some isolation transformers are better than others, but generally they need to be massive in order to begin to be transparent. There are a few audiophile transformer products that are acceptable for all but amps, but finding one that steps up or down is more difficult - Ensemble being one, and the PS Audio regenerators have a 220V version that adds a step-up transformer - not what you want anyway.
So I reckon the best thing to do is insist on knowing whether the voltage is reconfigurable before buying - anyone with much electrical nouse will be able to tell by looking inside usually. You will find most are reconfigurable these days, but it is fair enough for someone in your position to let retailers know that you expect the gear to be playable anywhere in the world, and then maybe manufacturers will have to adapt.
So I reckon the best thing to do is insist on knowing whether the voltage is reconfigurable before buying - anyone with much electrical nouse will be able to tell by looking inside usually. You will find most are reconfigurable these days, but it is fair enough for someone in your position to let retailers know that you expect the gear to be playable anywhere in the world, and then maybe manufacturers will have to adapt.