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Open Box Radial Engineering JDI Duplex Stereo Direct Box

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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 in... Click To Read More About This Product

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Gear returned in mint condition. If you're looking for a virtually new instrument in possibly less-than-perfect packaging, this is a great value.
  • Includes 45-Day, No-Hassle Returns
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Gear returned in great condition, with only minor signs of use, such as slight scuffs or pick marks. It looks and plays like new and may be considered an equivalent to display units found in retail stores.
  • Includes 45-Day, No-Hassle Returns
  • Includes full manufacturer's warranty
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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 and easy to use while delivering the utmost sonic quality.

Like the Radial JDI, the Duplex employs two high-performance 'made in the USA' audio transformers and 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 ΒΌ' 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 mu-metal 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.


-10dB RCA connectors
+4db XLR inputs
Jensen transformer-equipped passive DI
100% isolation eliminates ground loops
Ultra linear response from 10Hz to 40kHz
Virtually zero phase & harmonic distortion
Exceptional signal handling
Eliminates hum and buzz from ground loops
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Pro Coverage gives you added warranty protection for your gear. Stepping in where the manufacturer's "normal wear and tear" coverage ends, our Pro Coverage program offers you upgraded coverage if your product ever fails Click To Read More About This Product.

Pro Coverage includes
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  • Free shipping (for returns or repairs)
  • 100% coverage for commercial use
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  • Free transfer of coverage to a new owner
  • Repair costs covered for up to five years from date of purchase
  • Repair authorization-toll-free by phone or via the web
Customer Reviews

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Radial EngineeringJDI Duplex Stereo Direct Box

(based on 1 review)

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Reviewed by 1 customer

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(7 of 7 customers found this review helpful)


Radial really knows how to design, engineer and build pro gear.


from Boston, MA

Comments about Radial Engineering JDI Duplex Stereo Direct Box:

I purchased this Radial JDI Duplex MK4 for interfacing my Yamaha XS7 unbalanced audio outputs to balanced inputs on main mixer in recording studio. This resolved a ground loop problem that was causing hum. (Why Yamaha uses unbalanced audio outputs, where my Roland Fantom X, Kurzweil PC3, and Roland RD-700GX keyboards all have all balanced audio outputs is a mystery to me. But that is another story...) Maybe I could have resolved the hum issue with less expensive gear, but I suspect I would have degraded the sonic output of the XS7 using anything of lesser quality than this unit. So how does the keyboard sound with the JDI connected in-line? Well, all I can say is that whatever comes out of the XS7 is exactly what it should be: Full depth of the immense palate of sounds that this keyboard puts out, no coloration, no distortion and NO HUM! This JDI MK4 uses the renowned top quality Jensen transformers and high quality circuitry. The construction of the unit is professional grade. It weighs almost 3 lbs and 'built like a tank'. The input and output layout was well thought out. The numerous features available on this makes it versatile for any DI application you may have. Just go on Radial's web site. The information there is a lot more than marketing hype and very informative. The excellent information I got from the web was the final determining factor that led me to choose the JDI Duplex MK4. Now that I have this unit, I know that I made the right decision. I normally do not have time to write reviews and I am not in the music retail or distribution business in any way, shape or form writing patronizing reviews for hypeing product. I just felt compelled to write a review to show my appreciation for the engineering and quality that Radial put into this box. I believe that credit is due where credit is earned and this JDI Duplex MK4 has certainly earned my positive review. And I am now going to add the JDV to my gear as I see a number of uses for that active DI in my setup. I know I won't be disappointed.

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