Hello, yesterday i installed a Hifonics Mxs12d2 with a Pioneer GM D9601 monoblock. Before i had another amplifier and and i also had have the gain max out because my subwoofer have no power. With this amplifier i have the same problem, gain is max out but i'm sure is not at 100% of its potential. My suspect is the head unit, a sony dsx a200ui, i think it have a problem with the pre out. What do you think guys?