Radial JDI, Passive DI Box, Radial Item R800 1010. The Radial JDI is a passive direct box designed to handle extreme signal levels without distortion of any kind. At the heart, the Radial JDI employs the world class Jensen JT-DB-EPC audio transformer, delivering a smooth, warm sounding Bessel curve, reminiscent of the finest vintage gear. ??Linear response from 10Hz to 40kHz ??Jensen Transformer equipped passive DI ??Virtually zero phase or harmonic distortion ??Eliminates hum and buzz from ground loops ??Passive operation, no power required