The SP505 only has 8voices of polyphony, mpc has 32 voices. make it on the mpc use the sp 505 only for things the mpc cant do or would take a real long time on the mpc, then put em back into the mpc. the sp505 has digital in but not out. i would say if you use only for the parts you need you could go analog all the way. just sample it to match or use the mpc mixer. If you get a 128 voice sound module with good drum sounds and sequence it with mpc its money. extremely velocity sensitive.