For AC motor, controller varies frequency. For DC motor, controller varies output voltage. Make sure you buy the right kind.
Speed Controllers - How do they work?
I'm trying to figure out how these speed controllers actually control the speed of a turntable. I have a Clearaudio Champion 2, and the motor has a single AC power cord coming out of it. If I plug the motor into the speed controller, how does the signal to control the actual speed get to the motor to slow down or speed up the table? Maybe I'm missing something here, but I'm confused about how they work. I'd consider purchasing one if they are really worth having. Can someone explain this to me?