I am having problems with my ONKYO501E unit. After a party i had in my house things just werent the same, the highs sound fine but the lower frequencies are crapp. For a listener who doesnt know anything they wont notice anything, i now need a sub to fill in that bottom end. i am not sure if i am coming across clear. Could this be a power supply problem, where maybe its burnt, i thought maybe the speakers (B&W602 S3 + LCR600 S3+PSW10) were a bit too loud and the amp bottomed out. They were all bi-wired during the party, still are. When I brought this unit home it was working fine but now the SONY STR DB780 sounds better than the ONKYO when this was the other way around. I did try a different set of speakers to make sure that it wasnt the speakers that were the problem(i tried the Polk Monitor40 to check), still the lower end was very thin and hollow. I have looked at the settings and that has made no difference( by the way this unit does not have the option to set the front speakers big or small). i need to bring the volume higher for the unit to sound half decent even then the bass sounds crapp.How do i fix this.