Abstract: A device for improving the quality of audio and/or video signals comprises a main electrical circuit comprising an integrated circuit arranged for producing an output pulse signal having a predetermined frequency, and a toroidal inductor having a magnetic core which has a central opening and which is surrounded by a conducting wire, said toroidal inductor being arranged to be powered by said output signal.The device is arranged between a power supply unit and a signal processing unit which is connected by at least a phase- and a neutral conductor to said power supply unit such that said conductors pass through said central opening of said magnetic core, said toroidal inductor creating an alternating magnetic field within its core when it is powered by said output signal, so that said magnetic field induces an electric field which acts on said conductors.