PortaFM uses a pair of cycle-accurately emulated FM chip cores for its main synth engine, switchable between OPLL (YM2413), OPL2 (YM3812) and OPK2 (YM7129). Another core is dedicated to the the drum sounds, and all of this can be layered creatively.
The unique 'lofi' quality of the OPLL, OPL2 and OPK2 chips 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!