I really have no clue which amps Romeo used on Paradise Lost... But he certainly sounds much better than he ever did. Actually, Romeo's tone on previous albums is one of the main reasons why I couldn't really get into Symphony X... as a guitar geek you sadly get hung up on these things. But let me be the first... well, maybe not the first... but let me say (now that's better) that Paradise Lost is one of the best discs to come out this year - it really rocks in a big way!
As for the technical side of things, I'm guessing that Romeo is relying mainly on a Powerball for recording, and that what caused this massive improvement has more to do with finding the right producer/engineer, than some major change in equipment.
Cheers
Eske