The gain in speed stability from a drive controller is unrelated to the benefit of rim-drive. Rim drive improves speed stability relative to belts by reducing compliance at the physical interface between the drive system and the platter. Rim drive is theoretically better than elastic belts in resisting modulations in stylus drag excited by musical transients. A drive controller cleans up the sinewave to the motor. The respective improvements in stability are unrelated but cumulative.
VPI's rim drive is a hybrid of belts and rim drive, with a flywheel that gives up some of its advantage due to larger circumference & slower rotational speed, and a theoretical higher noise level induced by the flywheel in contact with the platter. Time will tell whether this is a net improvement.
VPI's rim drive is a hybrid of belts and rim drive, with a flywheel that gives up some of its advantage due to larger circumference & slower rotational speed, and a theoretical higher noise level induced by the flywheel in contact with the platter. Time will tell whether this is a net improvement.