I was around during the days of the first prototype.  I recorded music and played music live with John during those days, and I always used to drag all of my guitar and bass player friends to his house to jam because it was a completely different thing if compared to the standard guitar/bass/drums approach and sound.
     I remember the sound used to freak people out because they had NEVER heard the tone and texture of the mandola, even though it was played through typical processors and amp/speaker combos.  (John played in stereo thru 2 amps and cabs.)  The resulting sound was a range of what I would describe as that of amazing tube distortion harmonics to a clean sound that was discreetly sweet and clear.  Of course the material that we usually played was John's own compositional arrangements which are reminiscent of something of a cross between Hendrix/Jethro Tull and quite eclectic for the rock or folk enthusiast.