All you'll need is a step-down transformer to covert from UK 230V to Japanese 100V, but as I've often said on here the sonic consequences of using such converters, and the noise they may inject onto the mains, are unpredictable.
Anyway, a company such as
TLC will be able to supply a suitable converter. You just need to find out the power consumption of the component you want to supply, and buy one with a suitable rating.