What are ground loops and how do I avoid them?
One of the most difficult troubleshooting tasks for the audio practitioner is finding the source of hum, buzz and other interfering signals in the audio signal. Often these are caused by “ground loops.” This unfortunate and inaccurate term (it need not be in the “ground” path, and the “loop” is not what causes the problem) is poorly understood by most users of audio equipment. A better name for this phenomenon is “shared path coupling” because it happens when two signals share the same conductor path and couple to each other as a result. Another semantic problem that should be addressed early on is the idea that “ground” is one place where all currents go. It’s not, there’s nothing special about calling a signal “ground,” current still flows through any path that’s available to it Referring to the discussion above regarding unbalanced signal paths, recall that there must be a complete circuit from the output of some device, through the input of another device and back to the “return” s
