Fosgate Signature

Just got this unit in a trade.Although it blows away the Project tube box se II it replaced, I am noticing a decrease in volume in one of the speakers. The unit has 2 switches for MM MC switching and I am noticing when one is switched from MM to MC the level does not change. However when the other switch is flipped from MM to MC it obviously has more gain. It also seems as if the loading choices do not change sonics at all. I am using an SPU Silver Meister with a TD-124 TT. Dont have any experience with this unit, maybe some other owners can shed some light on this situation.