For what it’s worth, I’ve had no issues whatsoever using a step down transformer with my Denon DP80 or my Kenwood L07D. In fact there’s a benefit; the transformer isolates the TT motor from the house AC supply so EMI from the motor cannot contaminate power to other gear on the same line. By the way, the Japanese are also on 60hz AC, so there is no problem with frequency.
Id say my Technics SP10 mk3 is the most perfect of my TTs. The L07D is held back a bit by its phono cable which is not easily replaced.