Nanda, my friend, Ray at CTC/Classic HiFi is the best man to answer your question. I can tell you this-with Ray's PSU the eddy brake must be disabled. This is part and parcel as to why Ray offers the PSU in the first place. The PSU allows the user to control the speed of the induction motor/idler/platter rim interface electronically rather than by applying varying amounts of resistance via the eddy brake. In theory and hopefully in practice the PSU smooths the motor by eliminating the physical resistance of the eddy brake and by supplying a better electrical feed more suited to the induction motor.
As to the 220/50 vs. 120/60, I think you are referring to the fact that you can convert a 220 model to US use with a different idler wheel. This is not ideal. But again, I suggest you ask Ray.
As to the 220/50 vs. 120/60, I think you are referring to the fact that you can convert a 220 model to US use with a different idler wheel. This is not ideal. But again, I suggest you ask Ray.