The Radial JDI is a passive direct box built around a high‑quality Jensen transformer, designed to deliver clean, natural instrument tone while eliminating hum, buzz, and distortion. It handles very high signal levels without clipping, making it ideal for bass, acoustic guitar, keyboards, and other high‑output sources. The transformer provides smooth frequency response—flat from 10 Hz to 40 kHz—and virtually no phase shift, so the sound remains tight and musical even under heavy transients.  Because it is fully passive, the JDI requires no power and performs both impedance matching and signal balancing through its transformer, which also blocks stray DC to reduce noise and ground‑loop problems. The steel “bookend” chassis protects the switches and connectors. Features like a ‑15 dB pad, ground lift, polarity reverse, merge function, and speaker‑level input make this device extremely versatile for stage and studio use.