Jim,
He runs his amps out of phase, one amp , the speaker is out of phase, with the other, I know thats part of his sound, and his V pedal is wired a bit different..
I hear it too. I also hear it on the Roses at the Ritz live CD on his "Why You Been Gone So Long" solo. Possibly Jay Dee was fooling around with a harmonizer, or maybe his chops are even scarier than we knew. Either or both may be true.