Hi James, I used a Omega Micro ribbon cable for years on my SME 20/2 power supply. Now I am using a Purist Dominus Ferrox.
I hear the same types of changes on the motor controller I hear with the power cord on say the pre amp.
I know it's strange, given it goes to a motor, then a belt then etc etc... but it's pretty obvious.
Also try putting your motor controller on cones, pucks or some sort of isolation, you'll hear that to!