It was listening to Traffic's album, John Barleycorn Must Die in 1970 and that's when I went out and bought the pickup and soldered the cup on my flute and sax and ran them thru echoplex etc. Chris Wood had the pickup on his sax - looks like it was on his mouthpiece rather than the neck in this video. I know I tried it both places and I had a lot of trouble with a drop of moisture blocking the hole (worse when on the mouthpiece, better when on the neck) and I'd have to blow or shake the water out every once in awhile:
EDIT: I remember that there was a Maestro box that had all sorts of sounds when you ran the pickup thru it. I never bought that but I tested it out at the music store a lot and thought about buying it.