I have the plate amp from a Cerwin-Vega CVT-300S, and i want to know if i can wire the subwoofer output from my computer sound card to the left input and the 120 watt subwoofer output from my shelf system to the right input on it? having two totally different sources and amounts of power, i dont know if i can do that or should i just install a double pole double throw switch on it?