The Radial JDI passive direct box is the kind of premium-quality direct tool you need for great sound and rock-solid reliability on stages and in studios anywhere. The Radial JDI features a Jensen isolation transformer to give you the best performance possible at all frequencies. This box can handle very high signal levels without distorting, and its passive design helps to eliminate 60-cycle ground loops. Great for everything from passive and active guitars and basses to analog and digital keyboards, the Radial JDI is a dependable, quality performer!
The JDI's Jensen transformer is the product of decades of experience in transformer production. This transformer delivers optimum audio performance offering outstanding linearity at all frequencies, combined with extraordinary level handling without introducing distortion.
The input panel features a 1/4" instrument input and traditional thru-put. An innovative “merge” function allows the thru-put to be converted to a second input, enabling stereo-to-mono summing. This is especially useful for interfacing stereo sources such as keyboards or CD players in live shows where audio channels are not always plentiful. The JDI also includes a -15dB pad for interfacing with higher output levels.
The output panel features a balanced 600-ohm XLR connector with pin-2 hot, following AES specifications. A polarity reverse switch toggles pin-2 and pin-3 to allow compatibility with older non-AES equipment and creative phase manipulation. The ground lift switch disconnects the XLR pin-1 ground from the JDI for 100% input-to-output isolation.
A second -30dB pad can be engaged and, when used with the -15dB input pad, allows the JDI to be connected in parallel with a speaker. This enables engineers to “tap” the sound from a guitar amplifier speaker post-distortion, adding another creative dimension. This mode incorporates a speaker emulation filter that rolls off highs and lows to approximate the sound of a 12" driver.
As with all Radial direct boxes, the JDI is designed for use in abusive environments such as fast-paced concert stages. An innovative book-end design protects switches and connectors by creating a guarded zone that makes them nearly impossible to damage.
The inner skeletal frame features a rugged 14-gauge welded I-beam construction that prevents torque from being applied to the PCB — the most common cause of direct box failure due to stress-induced intermittent solder joints.
A full-bottom no-slip rubberized pad keeps the JDI firmly in place when resting on an amplifier and adds electrical shock resistance by shielding the unit from metal amp handles that are often directly coupled to the amp chassis.
The JDI is a high-performance passive direct box built for live concert touring and professional studio recording. Equipped with a premium Jensen transformer, it delivers exceptional audio performance with unrivaled clarity, reliability, and sonic integrity.
The Radial JDI is engineered to handle extremely high signal levels without introducing any form of distortion. At its core is the world-class Jensen JT-DB-EPC audio transformer, delivering a smooth, warm Bessel curve reminiscent of the finest vintage equipment. With a ruler-flat response from 10Hz to 40kHz and virtually zero phase deviation, the JDI reproduces the natural, pure sound of your instrument without coloration or artifacts.
Thanks to its passive, no-power design, the JDI performs both high-to-low impedance conversion and signal balancing over a magnetic bridge that transfers audio while rejecting stray DC voltage. This makes it extraordinarily effective at eliminating hum and buzz caused by problematic ground loops, ensuring clean, professional-grade performance in any environment.
