Radial J48, Active DI Box, Phantom Powered, Radial Item R800 3001. The J48 is an active direct box for live concert touring and professional recording studio applications. Most battery-powered instruments and stereo keyboards will produce as much as 7 volts when played at maximum volume, which can easily overload typical active direct boxes which are only able to handle around 3 Volts. The J48 uses a unique switching power supply that raises the internal rail voltage so it can handle up to an incredible 9 Volts, resulting in improved signal handling and greater headroom. ??Exceptional headroom & dynamic range ??Retains the natural sound of the instrument ??Merge switch sums stereo instruments to mono ??Powered by 48V phantom, no batteries required