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Radial Engineering JDI Duplex Mk4 Stereo Direct Box
  • Radial Engineering JDI Duplex Mk4 Stereo Direct Box
  • Radial Engineering JDI Duplex Mk4 Stereo Direct Box
  • Radial Engineering JDI Duplex Mk4 Stereo Direct Box
  • Radial Engineering JDI Duplex Mk4 Stereo Direct Box
  • Radial Engineering JDI Duplex Mk4 Stereo Direct Box
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Radial Engineering JDI Duplex Mk4 Stereo Direct Box

Manufacturer: Radial Engineering

Item #: RAD-DUPLEXMK4   •   MFG #: R800 1020


List Price:$374.99
Our Price:$349.99

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More on the way, usually ships in 3-10 business days
This item is currently out of stock and will ship the minute we receive it – typically 3-10 business days. Need it sooner? Expedited delivery options may be available. Email [email protected] or call customer service at 800-522-2025 and we'll make it happen.

    California Residents:
    Cancer and Reproductive Harm -


    The Radial JDI Duplex is a full-feature, stereo passive direct box designed to enhance connectivity, reduce noise, and simplify the hectic life of the touring professional, broadcast engineer or AV integrator. It is plug-and-play easy to use while delivering the utmost sonic quality.

    Like the Radial JDI, the Duplex employs two high-performance Jensen audio transformers with the same pristine audio signal path that has made the JDI the industry standard. It features exceptional signal handling with virtually zero phase shift or harmonic distortion, while remaining linear across the entire audio spectrum. When driven to extremes, the natural transformer saturation and resulting warm Bessel curve makes the Radial Duplex the perfect choice for smoothing out highly dynamic instruments such as digital pianos and electronic drums that can sound harsh when pushed. Transformer isolation provides the additional benefit of eliminating troublesome ground loops that can cause hum and buzz in the audio system or interfere with video displays.

    This 'Swiss Army knife' DI is equipped with 1/4" connectors for instruments, RCA connectors and a 3.5mm TRS for unbalanced -10dB consumer electronics plus XLR inputs for +4dB professional line sources. Radial's innovative book-end design provides protective zones on the front and rear to keep connectors and switches out of harm's way. The 14 gauge I-beam inner frame adds tremendous rigidity to eliminate outside stresses that could torque the PC board and cause premature solder joint and trace failure. The steel outer shell couples with the transformer's MuMETALr shield to protect against stray magnetic fields from power transformers or lighting systems that could cause interference. Finally, a full-bottom no-slip pad works double-duty by providing both mechanical and electrical isolation. The Radial Duplex delivers outstanding connectivity, superlative audio and quiet dependable performance..

    JDI Duplex. the world's finest passive stereo direct box.

    JDI Duplex Applications

    Duplex with Stereo Keyboard(See fig 3 above)
    The Duplex is able to withstand huge transients without distortion. This gives digital keyboards a warm, smooth vintage tone.

    Duplex with Two Stereo Sources(See fig 4 above)
    With the dual stereo architecture, the Duplex can easily be set up to handle two different stereo sources at the same time.

    Duplex in Multimedia System(See fig 5 above)
    Whether you have a CD player, iPod, computer or professional +4dB balanced source, the Duplex can handle any situation

    • Features

      • Stereo direct box for high output sources
      • Ultra linear response from 10Hz to 40kHz
      • Virtually zero phase & harmonic distortion
      • Eliminates hum and buzz from ground loops
    • Specifications

      • Audio circuit type: Passive, transformer based
      • Number of channels: Dual channel (stereo)
      • Frequency response: 20Hz ~ 20KHz (± 2dB)
      • Dynamic range: 135dB
      • Maximum input: +20dB @ 1kHz
      • Total harmonic distortion: 0.001%; 1kHz/+4dBu; 600 Ohm load
      • Phase deviation: -1° @ 20Hz; 0.5° @ 150Hz; 600 Ohm load
      • Input impedance: 140k Ohm PAD off; 10k Ohm PAD on
      • Input impedance - balanced FXLR: 10k Ohm
      • Output impedance - balanced MXLR: 600 Ohms
      • Transformer: Jensen JT-DBE
      • Shield: Dual Faraday, MuMETALr can
      • Input pad: -15dB (¬" and RCA inputs only)
      • Sub mono: Resistive summing mixer
      • 180° polarity reverse: Toggles pins 2 and 3 at the XLR outputs
      • Ground lift: Disconnects pin-1 at XLR output
      • XLR input: +4dB balanced female XLR
      • XLR configuration: AES standard (pin-2 hot)
      • Connectors: 1/4", RCA, 3.5mm TRS in, XLR-F in, XLR-M out
      • Construction: 14 gauge steel chassis & outer shell
      • Finish: Durable powder coat
      • Size: (W x H x D) 160mm x 48 x 127mm (6.3" x 1.9" x 5")
      • Weight: 1kg (2.2lbs)
      • Shipping size: W x H x D: 210 x 159 x 83mm (8.25" x 6.25" x 3.25")
      • Shipping weight: 1.43 kg (3.15 lbs)
      • Power: Passive, no power required
      • Conditions: For use in dry locations only between 5°C and 40°C
      • Warranty: Radial 3-year, transferable
    • GTIN:


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