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Radial Engineering
JDI Passive Direct Box

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Item: N12-1404

Availability: In stock

JDI Passive Direct Box
JDI Passive Direct Box JDI Passive Direct Box JDI Passive Direct Box JDI Passive Direct Box JDI Passive Direct Box

Radial JDI

The JDI Passive Direct Box, from Radial Engineering, is a robust, transformer-isolated passive direct box that affords complete isolation that results in drastically reduced noise. The box is ideal for both studio and stage environments, as it adequately preserves the integrity of the input signal by providing low phase distortion, low harmonic distortion, and nearly perfect linear response. On top of all that, the JDI is houses inside a story chassis that will provide ample protection while on the road or in transport. 

In terms of construction, the JDI is designed with a bookended chassis that protects the switches from damage. Additionally, it is comprised of scratch-resistant baked enamel, complete with a rubberized pad across the bottom. The purpose of the latter feature is to prevent the unit from moving and emphasize the isolation. This robustness extends to the JDI’s interior, which features a welded I beam designed to guard the electronics from any outside pressure. 

Functionality-wise, the JDI contains a 1/4” instrument in and thru-put, with an additional merge function affording the ability to reconfigure the latter jack into a second input for stereo and mono summing. This ability makes the unit ideal for usage alongside keyboards and audio players. It also features a -15dB pad for grappling with higher output levels. For even further creative experimentation, the unit features a -30dB pad that can be used alongside the -15dB input to connect the unit to a speaker in parallel.

JDI Features

  • 100% passive design - no phantom power
  • Dual function inputs w/2 channel merge
  • Polarity reverse switch
  • Speaker level input circuit
  • Ultra-durable welded steel chassis
  • Double sided printed circuit board
  • Protective channel for switches
  • Ground Lift and Pad switches
  • No-slip bottom pad


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  • Dynamic range: 135dB
  • Signal to noise: 119dB
  • Maximum input level: +19dB
  • Frequency range: 10Hz~40kHz
  • Linearity 20~20kHz: 0.1dB
  • Phase coherence: 4 degrees at 20Hz
  • 0 degrees at 1kHz
  • Distortion at 20Hz: 0.006%
  • CMR rejection 100dB @60Hz
  • Input impedance: 10kW
  • Output impedance: 600W
  • Construction: Welded steel
  • Finish: Baked enamel
  • Input connectors: Two 1/4" phone
  • Output connectors: XLR male

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