Hi, all...been following this thread with frustration, until today. I retraced my steps and made sure my settings matched Techfreak's suggestions, yet the buzz/drone continued. However, I then took a closer look at this 'Listen' tab:
"Listen to this device" was unchecked by default, but the change I made was to switch to "Speakers" from "Default Playback Device" and voilà! No more annoying buzz. Thanks everyone for your suggestions, I hope this can work for others also.