PortaFM uses a pair of cycle-accurately emulated OPLL (YM2413) FM chip cores for its main synth engine, and another core dedicated to the the drum sounds, all of which can be layered creatively.
The unique 'lofi' quality of the OPLL was never recreated this accurately before. Plogue's experience of more than 15 years studying vintage digital sound generators was pushed to its limit. Brand new mathematical models were built using our custom Hardware-assisted systematic testing procedures by our in house reverse engineering team in Montreal.
Oh, and of course, it does not use ANY samples!