Does anybody know what the main differences are between the 525 and 7200? I know the wattage difference. It looks like they use a slightly different dsp chip. I don't know if the one in the 7200 is significantly better or just different. Are the preamp sections pretty much the same, or am I missing something? I have all deftech speakers currently. Fronts and center have powered subs. So power isn't the biggest concern. The cleanest preamp is the biggest concern for me. What do people think?