If you can hear a hum or buzz through your speakers, it is likely that you have a ground loop problem. This occurs when two or more audio components in a system are connected to a common ground (or earth) point via different paths – for example, if two different wall sockets on the same circuit are used to power different components in a single audio/AV system in which the components are connected via electrical (as opposed to optical) signal cables. If a problematic ground loop exists, the GND Defender resolves the issue by disconnecting the loop running through the connected component. By using one or several GND Defenders in a hi-fi system, the user can ensure that all components are connected to a common ground via a single path, eradicating the resulting hum through the speakers. Interference caused by ground loops can also affect picture quality in AV systems, resulting in issues such as visible scrolling bands. The GND Defender will help to solve this problem, too. Both the DC Blocker and GND Defender are constructed so that they do not compromise the RFI/EMI shielding or filtering that may be offered by the connected power cable or filtering device further upstream.