Turn off all equipment & unplug everything. (This also gives you a chance to clean/check all connections) Start over but just connect the spkrs to the 7BST's. If there's a hum, there's your problem. If not, go through the hook-up sequence one piece at a time until you locate. Make sure to turn off all gear everytime you connect/disconnect.
It's been my experience if it's not the component itself the AC is the culprit and most of the time it's the AC & not the component. If it turns out to be the AC, do a search through the archives for ways to address this. Good luck.
It's been my experience if it's not the component itself the AC is the culprit and most of the time it's the AC & not the component. If it turns out to be the AC, do a search through the archives for ways to address this. Good luck.