I am preparing for a similar move.
If there are no motors in a particular component, you can use a step down voltage converter. I would buy high quality converters with a higher voltage rating than your components require. Todd seems to make one of the better converters available.
Note that these converters convert voltage only. Voltage and frequency converters are available, but they are so pricey that you would be better off replacing the component with a unit compatible with 220/50. Components with motors, especially turntables, need the proper frequency in order to operate properly. I will be purchasing a turntable with a switchable power supply. I think some indicator panels may also be sensitive to the frequency of the power supply.
If you want to buy 220 electronics, there are sellers in the US that specialize in electronics for 220/50. However, they mostly sell mid-fi stuff. My US made preamp will be sent in to a service facility for conversion to 220/50.
I have done a lot of research on this topic. If you have more questions, feel free to ask here or PM me.

