Yamaha CS80

Hi All,

Does anyone know perhaps how Eddie Jobson gets that sweeping, morphing
effect CS80 effect behind Allan Holdsworth's amazing guitar solo on In
The Dead Of Night? It almost sounds like it's being arppegiated, but
he's definately going back and forth between the 2 voices on the CS.
This has had me stumped for years. I almost think it could be a quirky
resonant hipass filter thing.

Thanks in advance,

Mark