What is good sound? Part 5: Absence of Noise

Absence of Noise

Are you hearing sounds you shouldn't? Hisses, Pops?

First let us lay some groundwork: audio systems can exhibit "hum " and they can exhibit "buzz ," which are two separate situations. To solve the problem, you need to determine whether your system is exhibiting hum or buzz.
Sixty(60)-hertz hum (fifty(50) hertz internationally) is a result of having a ground loop in the audio system. This is where there are two or more ground references in the system, and current is flowing from one ground point to another. Any piece audio equipment requires one ground reference.