Hey, I just got my 4 pro brand new today and i love it. There is a minor problem though. When the master is even at zero the preamp clipping light comes on when I play. I do not play an active bass, but when I press the -15 db switch, this fixes the problem, and the pre amp clipping light only goes on when I hit hard notes. I can still get a good volume out of it, since it is mono bridged at 4 ohms, but I know if I dont use the switch, it can go way louder. I just find it strange that the preamp clipping light goes crazy even when the gain and master are at VERY low settings.