The PSU1 offers a significant increase in sonic performance from the standard power supply on any Graham Slee product with a standard wallwart power supply Today’s domestic electricity supply can prove problematic for the committed audiophile; voltage variations and spiking within the AC supply can seriously detract from the listening experience For those customers who do not intend to rewire their house, or spend small fortunes on miracle block/cables, the Graham Slee Projects PSU1 power supply is now available.