The electrical setup (and room construction/acoustical setup) are the foundation of the listening experience. We all love to talk gear and this stuff is not sexy. The fact remains that all of us have electrical distribution in our houses that complies with code for safety but was built to a budget. A little attention to where the neutral bonds to ground, the number of rods used for the ground and their impedance will dictate how your system responds to noise. I would recommend having an electrician check the condition of the grounding rod (in free standing houses), if possible have them sink in a couple additional. Tie them together with good copper and build a buss bar ground at your breaker/disconnect. You can use copper ground strap to tie the ground rods to the buss if possible. Ground strap has much more surface area and therefore less impedance at higher frequencies which will provide more lightning protection and a better RF shunt. My personal preference is for balanced power. It allows for common mode cancellation in the primary of the individual equipment, separating the neutral from ground, lower shock hazard and balanced current draw. I build my gear with schurter iec inlets that have dual fuse protection and ground chokes to take advantage of balanced power where available.Additionally, in my experience, power filtering in the digital side of my audio rig has provided benefits.