You didn't mention whether or not you have a power conditioner. I had a very slight hum/buzz with the volume turned up and nothing playing until I got a power conditioner and the noise vanished. It also provides protection form spikes, like lightning hits.
I'd recommend one, and as far as a power cord goes, I think $100-150 is right. According to the cable company, the longer the power cord, the better (opposite of interconnects and speaker cables), but don't make loops out of excess cord as that creates a magnetic field. Try to keep cables from touching each other, especially if running parallel. I have entry level signal, gutwire and wire world, and they're fine. Just make sure it is flexible. My signal one is thick and hard to maneuver.
I'd recommend one, and as far as a power cord goes, I think $100-150 is right. According to the cable company, the longer the power cord, the better (opposite of interconnects and speaker cables), but don't make loops out of excess cord as that creates a magnetic field. Try to keep cables from touching each other, especially if running parallel. I have entry level signal, gutwire and wire world, and they're fine. Just make sure it is flexible. My signal one is thick and hard to maneuver.