how do u set up the midi between these two machines?
Assuming the MPC has MIDI DIN out -
Connect the MIDI OUT of the MPC, to MIDI IN of the Slim Phatty.
Provided both are set to the same MIDI channel, you should be good to go.
If the SP is 2nd hand and/or has been subjected to a lot of menu reconfiguration, you might want to think about doing a factory reset on the SP so all the MIDI parameters will be set to their defaults. If you don’t have a manual for the SP, it’s available as a free download off the Moog website.
Randy