The Akai MPC500 (eBay) was the first ever truly portable MPC as it could be run on 6 AA batteries (also a 12V DC plug). It combined a 48-track MIDI sequencer and a 32-voice stereo digital sampler. This was the only MPC to have just 12 velocity-sensitive rubber pads. Like the rest of its family that was released a year prior, the MPC500 came with a CompactFlash slot, was upgradeable to 128MB RAM, and had a USB port for computer connectivity. With just one stereo output, this was the only MPC that didn’t have assignable outputs.