vpi classic works with music hall cruise control

IMO, the primary function of the VPI SDS is not necessarily a speed controller but more a voltage regulator. It uses full voltage on start-up then reduces voltage when the table is up to speed. This results in a reduction in the pulse of the synchronous motor. Speed control is also available on the SDS.

The Cruise Control (TTBOMK) is only a speed controller.

And the speed control will do little since the motor speed on the VPI is pretty much OK without the control. The SDS is all about voltage management. That's what makes the big difference.