The J48 is an active direct box that has been optimized to handle extreme transients without distortion, with a linear frequency response that extends from 20Hz up to 40kHz.
Most battery-powered guitars and basses will produce as much as 7 Volts when played at maximum volume, which can easily overload typical active direct boxes which have are only able to handle about 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. This additional headroom significantly reduces distortion of all types, allowing the natural tone and character of the instrument to shine through.
The Radial J48 has gained a tremendous following through the professional audio community. With significantly more headroom, lower distortion and unmatched durability, it is no wonder that the J48 has become the most specified direct box on stages around the world. As you will note with the specifications below, the J48 is exceptionally linear when tested both under laboratory conditions and when placed under the extra stress of 100 meters (300 feet) of cable. In the lab, the high frequency response actually exceeds 40kHz! This makes the J48 a perfect candidate for the most demanding studio recording while being the obvious choice for the artist on stage.