It's worth noting I think that there's a good deal more going in Evolvers as compared with the Prophet/Mopho/Tetra architecture. It's not as simple as adding a few more voice / filter chips - for a start you need the DSP to do the digital oscs, delays, HPF, distortion etc., and you need those additional AD/DA stages to integrate the two as well. So it's quite a bit more complicated and certainly needs more parts.
