For music freaks

That voltage fluctuations and frequency variations spoil the fun of hi-fi digital sound systems is the complaint of many a music fan. PS Audio, a company based in Avon, Colorado, USA, has developed a device worth US $1,000 that delivers a pure waveform when plugged into the electricity mains. The device takes power from the mains and converts it from AC to DC and back again. The systems relies on a digital signal processor.