Most of his samples are available also as .wav. I just mention this because of Espen's recent comment of "enjoy it while you can" with regard to the Prophet X (which I'm sure someone will find a way to keep working 40 years from now), be sure to get them in the right format so you can use them forever, as some of them are quite good, he has invested a lot of time.
I have many of his sample packs and sometimes send them into SpectraLayers for harmonic manipulation, then into the 3rd Wave, which is a limited sampler in terms of storage but has amazing filters. Sometimes the sonic result of that through analog filters is nothing that any of my software samplers can even come close to. I attribute a lot of that to the circutry of the 3rd Wave but I assume the PX is similar.