Hello! today i installed my sony xm-1s sub amp and a magnat 12 inch sub.all the wiring is correct since i tested the system with different amp and no problem occurs.the problem with the amp is that even it is set to max gain the output sub volume is way less than 250 rms that the amp supports at first i used the DMM to calculate the proper output voltage using a test tone then connect the sub , and the volume is way to low! checked fuses and are ok checked the input voltage and its correct to.that means that my amp is partially blowned ?