I picked up my towers from the repair depot today. They went in for a buzzing noise coming from the sub when everything was shut off. The repair guys replaced both amplifiers and said that they are good to go.... Here is my dilemma, the two amps do not look similar, whay is this? Was there a change in parts due to a known problem? Did I get a wrong amplifier in one of my towers? I hope that you guys can help me out here.