The design of the 7700 and 7500 are different than the 7125. Outlaw's Description, "The 7700/7500 differential design virtually eliminates cross talk, through a technology known as "common mode rejection". Compared to single-ended designs, the 7700/7500 requires half the rail voltage for a given power allowing for increased transient performance."

I replaced an Outlaw 770 amp (7 x 200w) with the Outlaw 7700 and there was more than a subtle change. I think the term transparency is the best I have heard. Even my wife agreed ,reluctantly, which has always been the "Mendoza Line" for me and audio purchases...

Cheers everyone!