Radial JDI Passive Direct Box

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Product Code: 1814
Radial JDI
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Radial JDI Passive Direct Box

The Radial JDI Passive Direct Box ensures the natural tone and harmonic balance is retained, bringing out the very essence of the instrument. Employing a Jensen audio transformer as the engine and being the world's finest direct box, the JDI delivers smooth, musical tones to the preamp.

The Radial JDI is a passive direct box designed to handle extreme signal levels without distortion of any kind. Unlike an active DI that is limited by the buffering amplifier’s rail voltage, the Radial JDI employs a Jensen audio transformer as the engine. Jensen transformers are legendary in their ability to gracefully handle transients while delivering a smooth, warm sounding Bessel curve, reminiscent of the finest vintage gear. Ruler flat from 10Hz to 40kHz and with virtually zero phase deviation, the Radial JDI delivers the natural, pure sound of the instrument without artifact.

The 100% passive circuitry inside the Radial JDI is incredibly efficient. The transformer performs both high-to-low impedance conversion and signal balancing at the same time with minimal loading and does so without any power whatsoever. The transformer also introduces a magnetic bridge that passes signal while rejecting stray DC voltage. This makes the Radial JDI particularly adept at eliminating hum and buzz caused by ground loops.

Features include input and throughput ¼” connectors, -15dB input pad, ground lift, and 180º degree polarity reverse to help phase align the instrument with the PA. A secondary circuit is added for direct interfacing with high output devices such as guitar or bass amp loudspeakers plus a unique merge function allows stereo sources such as keyboards to be summed mono, saving valuable input channels.

Built tough to handle the abuse of live touring, the Radial JDI features a 14-gauge steel I-beam inner frame and a unique book-end outer shell. The innovative design eliminates stress on the PCB, reducing opportunity for solder joints to go ‘cold’ while the outer shell creates a protective zone around the switches and connectors. The steel casing resists noise-causing electromagnetic pollution and the transformer’s sensitive inner workings are further protected from magnetic fields with a MuMETAL® can. This ensures the signal transfer is quiet and free from hum.

These combined features have made the Radial JDI the most popular passive direct box in professional touring and an excellent choice for instrument interface in the studio!

Radial JDI Passive Direct Box Features

  • Jensen Transformer equipped passive DI
  • Eliminates hum and buzz from ground loops
  • Virtually zero phase & harmonic distortion
  • Exceptional signal handling and noise rejection
  • Best-sounding passive DI in the world
  • Authentic Jensen Transformer equipped passive DI
  • Linear frequency response from 10Hz ~ 40kHz
  • Extraordinary level handling without distortion
  • Built to survive the road
  • Plug-&-Play Design - Easy-to-use!
  • No battery or phantom-power required
  • Impossible to overload!
  • Up to 8 may be rack-mounted with the J-Rak

Radial JDI Passive Direct Box Specifications

  • Specs:
    • Audio Circuit Type: Passive, transformer based
    • Number of Channels: Single channel (mono)
    • Frequency Response: 20Hz ~ 20KHz (± 0.2dB)
    • Dynamic Range: 135dB
    • Maximum Input: +21dB @ 20Hz ~ 20kHz
    • Total Harmonic Distortion: 0.05% from 20Hz ~ 20kHz @-10dB
    • Phase Deviation: 0.3° @ 100Hz; 3° @ 20Hz
    • Input Impedance: 140k Ohms, unbalanced
    • Output Impedance: 150 Ohms, balanced
  • Features:
    • Transformer: Jensen JT-DBE, 12:1 ratio
    • Shield: Dual Faraday, mu-metal can
    • Input Pad: -15dB
    • Merge: Sums left & right sources to mono
    • 180-degree Polarity Reverse: Inverts absolute phase
    • Ground Lift: Disconnects pin-1 at XLR output
    • XLR Configuration: AES standard (pin-2 hot)
    • Speaker Filter: -30dB pad and band-pass filter
    • Connectors: 1/4-inch in & thru, XLR-M out
  • General:
    • Construction: 14 gauge steel chassis & outer shell
    • Finish: Durable powder coat
    • Size: (L x W x D) 5" x 3.3" x 1.8" (127mm x 84.1mm x 45.5mm)
    • Weight: 1.55 lbs (703 grams)
    • Shipping Size: L x W x D: 6.5" x 4" x 3" (165mm x 102mm x 76mm)
    • Shipping Weight: 1.92 lbs (870.9 grams)
    • Power: Passive, no power required
    • Conditions: For use in dry locations only between 5°C and 40°C

Radial JDI Passive Direct Box Applications

  • Ideal for acoustic guitars and basses
  • Keyboards, modules and electronic drums
  • Great with high-output, electronic instruments
  • Eliminates hum & buzz in sound systems

Radial JDI Passive Direct Box Includes

  • Radial JDI Passive Direct Box
  • Manual & Literature
  • Radial Sticker
  • 3 Year Warranty

Radial JDI Passive Direct Box Downloads

What We Think

The Radial JDI Passive Direct Box is an indispensable tool in my audio-toolkit, whether it be in the studio or when I mix or record live sound. My Radial JDI Passive Direct Box sees as much action as my most used microphones. It's beat up and weathered. But it never misses a note. I keep a short jumper instrument cable with it and insist on using it. Why? Most DIs included in bass and keyboard amplifiers are well-intended cost-effective additions that unfortunately end up being unintended problems when put into the real world. Electronic noise and a hard and unmusical, two-dimensional sound are but a couple of the results that have plagued me when resorting to using an on-board DI. A quality DI signal simply requires quality components. And the Radial JDI Passive Direct Box makes for one of the best quality signals that I have encountered. Basically, I look at it as not having any detrimental effect on the sound. The Jensen transformer has a frequency response that is incredibly flat, yet it lends a certain 'energy absorption' character that is very musical when a bass string is plucked extra-hard, or a keyboard part gets particularly 'stabby'. So, when I'm wiring a stage and the musician starts to point me to their onboard DI, I politely decline and explain that we've got that covered with a dedicated unit that will kill any potential noise. And that's the truth. Plus, due to the wide variations in rock-club design (I use the term "design" rather loosely) and PA placement sometimes the FOH sound can be out of phase with the onstage amp, and the bass player's reference disappears. The 180-degreee button solves this problem by inverting the signal going to the front of house / monitors. The 'Merge' button will take incoming signals from both the Input and Thru jacks and sum them to Mono; perfect for stereo-only keyboards or other instrument level sources who you don't need to waste a 2nd valuable DI or channel for summing down to mono. I also own a Radial J48 which is my go-to for a lot of acoustic guitars and anything that has a lower output that could use a little help. Conversely, the Radial JDI Passive Direct Box usually likes a little more juice from the mic preamp than, say, 'unity'. But the Radial JDI Passive Direct Box simply would be my desert island DI. I can do anything with it, and know that it'll be there for me - even if it falls off a 10-story building or run over by an 18-wheeler, or whatever."

- Front End Audio

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8 Reviews Hide Reviews Show Reviews

  • 5
    Excellent di box

    Very nice for bass guitar. I have a music-man I plug into this thing and it is pro sound. Not a complaint very happy.

  • 5
    Excellent/RADIAL JDI review

    This product performs as expected and does not disappoint. Just beginning to explore all the possibilities.

  • 5
    Blue EnCore 100 mic's

    Excellent Mics. Quality Build. Outstanding service and support from Front End Audio. As always....

  • 5
    Perfect DI

    From acoustic guitars, bass, keyboards, and whatever else I've thrown at this DI, it has captured everything very musically without any problems what so ever.

  • 5
    A workhorse

    Cheap DI boxes can screw up the sound and add noise. I learned that the hard way.. Not this one! I use one in my home studio and it sounds great. It adds alittle thickness (but it never gets muddy) to the signal. I also use a bunch of them at the venue when I do live work. The venue also have a few other DI boxes but I always use the Radial JDI's because the excellent reliable build quality.

  • 5
    Solid as always

    JDI products in general are absolutely top-notch. This DI box is no different. From studio work with bass guitar to live acoustic guitar, etc. my JDI Passive Direct Box always sounds great. If I ever lost this or if it was ever stolen I would replace it immediately with the same. There would be no question about it.

  • 5
    Best passive DI on the market

    The JDI passive DI should be an essential componenent of any gigging or recording musician. Even at many well attended venues, the fact remains that they often cut corners on DIs, buying cheap. If you plan to gig acoustic guitar, it pays to keep this in your case. It is also fantastic for recording when you want to take a transparent direct take while you are miking your acoustic, which allows you to blend the tones if desirable ( and if your guitar has a quality preamplifier). I even like to run a dry direct signal from my bass into the JDI and use the thru-put Jack to connect to another preamplifier/DI, such as the Aguilar Tone Hammer or the UA Solo 610. When you capture an inspired take, this gives you options at the mix down stage to choose the mix that best sits in the mix, and can save a lot of time from the quagmire of processing the bass line until it's sits well. If you need a passive DI, this is the one you ought to buy

  • 5
    Radial JDI

    This is an awesome DI. I use it for guitar, keyboards, and for reamping. It helps to smooth out any harshness in keyboards, guitars, smooths it out. I use it all the time and it does what it's supposed to and does it really well.