This goes back a ways (decade-plus) back when Mark Abrahamian was around... I think a lot of people listened to his VH tone test clips (he used a Super Distortion), and he got close, so people jumped on the "Ed used a DiMarzio Super Distortion" train.
I OTOH am convinced it was the Seymour Duncan SH-5 Custom (or prototype for Ed) in the Frankenstrat... based on magazine evidence, interview evidence and most importantly, gear testing evidence and tonal evidence.
For exhibit A (LOL), I give you my guitar with an SH-5, emulating studio magic and using real backing tracks - for Runnin' With The Devil: