There's a particular pickup combination which I use for the violin things: the fingerboard pickup and the middle one. Those two working in phase make a very mellow sound. And there's a point on the amplifier where it's just about to get distorted, but not quite. Instead of using my pick, I tap the fingerboard with the right hand, and that just sets the thing moving. It sustains itself. You hardly need to even tap it any. If you even stand in exactly the right place, it feeds back in any position so I can just warble around and it's very smooth. I also used that tone for the beginning of Leaving Home Ain't Easy on Jazz. For that, I actually used the studio faders to fade them in, but that was the same sort of sound.