Q: "What's the difference between RFI/EMI and hum or buzz?"

A: Well, in some cases, hum or buzz can be a form of EMI, or electromagnetic interference. This happens when nearby sources (inexpensive light dimmers can be the worst culprits) induce a 60 Hz hum or buzz in audio equipment. Another common cause of hum or buzz is ground loops. These occur whenever a system has two or more paths to ground separated by a distance. The ground paths can be through the shields of connecting cables, the safety ground on the AC cord, and/or even between chassis bolted to a common metal rack. Ground loops can be broken using isolation transformers or telescoping shields on the audio cables or through various schemes of AC wiring. Call your Sweetwater Sales Engineer who can prescribe the right remedy.