Re: Petrucci used an ADA??
Part of it is that almost everyone who played guitar throughout the 80's & early 90's used one at some point. It doesn't mean it was ever part of "his sound" for an album or tour. I don't like the ADA's, but I had one for a few months back in the day, too. And every once in a while I get the itch to get one to have around again, and it usually passes in a day or so. I've got a Boogie Quad and a Marshall JMP-1 now, so I can't imagine the ADA offering anything I don't have right now.
The H&K Attax head will get you much closer to DT and other Petrucci sounds than an ADA. I mean, when you plug into the ADA does it make you think of DT? Not me. Unless someone has contrary information, like it was THE sound he used on some album, etc, I'd say it's just because everyone had one. I had a Rockman 15 years ago, too!