When you had the laptop connected did you also have the charger plugged into the laptop? The buzz could be coming from the battery charger.
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Outlaw Audio Model 990
Outlaw Audio Model 7500
Polk Audio RTi150, CSi40, FX500i, PSW650
Sony KDS-55A2000
Onkyo DX-C390
Toshiba HD-A2
DirecTV HR20-700
Philips Pronto TS-1000
Pics of My System