When two or more components are connected to a common ground through different paths, a ground loop occurs. Current flow through these multiple paths can cause noise or a 50Hz/60Hz hum.
To eliminate ground loops, all signal grounds need to go to one common point. When multiple grounding points cannot be avoided, you must isolate the signal and grounds of each ground point from the other.
Some components do not really need to be grounded directly; so eliminating the ground connection on that component will also solve the problem. An AC "cheater plug" is a quick fix, and/or an easy way to test each AC connection and locate the offending connection.
A power filter or conditioner by itself will not solve a ground loop hum.
To eliminate ground loops, all signal grounds need to go to one common point. When multiple grounding points cannot be avoided, you must isolate the signal and grounds of each ground point from the other.
Some components do not really need to be grounded directly; so eliminating the ground connection on that component will also solve the problem. An AC "cheater plug" is a quick fix, and/or an easy way to test each AC connection and locate the offending connection.
A power filter or conditioner by itself will not solve a ground loop hum.