Pro-Ject High Power It Power Supply - 15V DC Power SupplyEvery turntable needs proper grounding, otherwise electrical hum may be induced. If a turntable is not properly grounded, it may have a different reference potential than the connected amplifier. Consequently, these potential differences induce a compensating current which can be heard as hum. Therefore all good turntables have a seperate ground cable which can be connected to standard amplifiers or phonostages, which usually have a ground terminal.