Depends what Cubase ur using. SX3 and C4 can slave to midi clock. im 100% on this because i use them.
Basicly Mini in 1 for your MPC, to midi out 1 of your Sound card/interface.
on mpc mode,pad9,F2,data wheel till you get 1 (Slave) at the top, then Mode: Midi clock below.
in Cubase, Devices, Device settings, midi, and make sure your output it visible and active
then, Transport, midi sync, i just use all midi inptuts under midi time code. set your destinations at the bottom, Most likly your Soundcard, and hilight "always send start message"
Done press play in cubase n ur mp will play too, When tracking out i give one bar of blank to make sure the time code is caught up.
Unders