Via power supplies, transformers, etc. the hi-fi devices themselves generate electrical interfering fields, in the immediate vicinity of the signal-transmitting components. In addition, the different power consumptions of the individual devices cause sound-damaging potential equalization currents, which are distributed to all devices via the cable connections. Furthermore, via the cables and device housings high frequency interfering fields from the environment radiate directly into the signal path of the devices and massively degrade sound reproduction quality.
Common solution approaches and their limitations:
In order to protect the sensitive audio signal inside the devices against impairment, developers of high grade devices try hard to keep interfering fields low inside of the devices by use of very low stray field components or by shielding enclosures. Power filter or grid generators may help keep external interfering fields originated from the power grid away from the device, but the inner interfering fields, caused by the equipment itself and close to the audio signal, cannot be cleared up this way.
High-frequency interfering fields, radiating from the environment via the housings of the Hi-Fi devices and the cables into the signal path, are not detected at all by upstream filters.
Previous ground solutions work by reducing potential equalization currents by discharging to protective grounding or a common central ground potential. Due to the nature of the system, such ground solutions do not have bidirectional connection lines to prevent interfering field transmission between the audio devices.
In addition, any discharging to protective grounding opens another window for interferences already present on protective ground to enter the audio system.