I have had so many hum issues over the years. Isolating the hum has sometimes been problematic. Even still I get noise from the electrical in here. Old panel, likely shitty wiring, as well as, poor circuit runs. I have lived in a lot of places in the last 10 years. Only place I had good electrical was in a room I reno'd in a place I lived at. I had installed 4 isolated circuits with 4" boxes and plaster rings allowing for 2 recepticals on each box.