I bought a 2 channel that was supposed to be brand new. I didn't check it when received(my fault), but now that I have hooked it up, I have engine whine from it(no whine from my other 3 amps, and the 2 xhannel replaced one in my setup). Today as I was doing some why checks, I found out there is no output in my left channel, but if I stick the rca in output it plays. The right channel plays but has distortion and whine. What could I be looking at as a problem?