Tech talk for the playas out there -- my axe back then was a Gibson Chet Atkins solid-body classic guitar, heavily customized for me by then LA luthier to the stars, Rick Turner.
Rick replaced the stock Gibson pickup with his own hex-pickup system (separate, discrete audio feeds for each string, necessary for proper synth triggering), which includes a unique hex filter, a device that reduces the signal fed a Roland GR-series guitar synth to as near a sine wave as possible, trimming out unwanted harmonic overtones so the synth sees a clear pitch fundamental, thus quickening and cleaning up the pitch-to-voltage MIDI conversion process. It's a brilliant system that Turner went on to offer in early models of his Renaissance line of guitars, of which, I'm proud to say, I own the very first production model.
RE: Mason Williams & Friends LIVE feat Jeff Foster