I'm a relative newbie to electronics, and as an educational project I'm building a record turntable. I'm comfortable with the purely mechanical aspects of the project, but I need some help understanding how to drive the motor.
I have a two-phase, bipolar stepper-motor that I'm trying to use to drive the platter via a belt. The platter will turn once for every six turns of a wheel driven by the stepper. Using a stepper-motor controller in micro-stepped (1/8th-step) mode provides great torque and speed control, but makes the motor much too noisy for this application since the tone arm on a turntable is very sensitive to vibrations.
If the accounts I've read are accurate, a motor like this one can be driven smoothly by applying a voltage sine wave on the first winding, and simultaneously applying a second voltage sine wave (offset 90 degrees) on the second winding. What is the best way to do that? I have found circuit diagrams for op-amp based sine generators which have a synchronized cosine output. Is the task as simple as using a pair of op-amps to amplify the generated signals and then using the amplified signals to drive the motor, or am I missing something that would prevent that idea from working? Is this whole scheme crazy for a reason I don't yet understand?
Thanks for any help you can provide.