As a direct-drive motor rotates, there are action-reaction forces set up between the platter and the base (cabinet), and between the motor rotor and the stator. These lead to tone-arm vibrations which cause poor sound reproduction. It is described how these forces can be minimized by adding a second motor or torque generator. The main drive motor and the second motor or torque generator are driven in reverse phase, which greatly reduces base (cabinet) vibration in the rotational plane. This technique provides a substantial improvement in tonal quality.
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