I have a cheap active subwoofer (KLH Bassbite V) that was part of a speaker system that included 4 satellite speakers and the active subwoofer. This took a low level L(mono)/R RCA input and it used its internal 25X25W amp (TI TD2050 IC based) to feed the sub AND the satellites using spring speaker terminals. I dont use the amp for the satellites as I have a 150W 7.1 A/V receiver (Sony STR-DN840) that the satellite speakers are attached to and are working fine. I want to rebuild the amp in the sub as I think its not working, no output with any input. Question is does the A/V receiver have a crossover internally that will do the 80HZ crossover or will I need a passive crossover in the sub enclosure? Im homing I can just build a 60W mono chip based amp and hook up the existing speaker in the sub enclosure. I had a buzz in the sub and no output so I replaced the 2 large 4700uf 25V filter caps with no change. Did not remlace the 2.2uf dc blocker yet, just found out its purpose. Amp IC gets very hot so I know its getting something.