Radial JDI Passive Direct Box Front View
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  • Radial JDI and Chick Corea
    Chick Corea

    "Radial direct boxes make everything I put through them warm, punchy and clear. They are great DIs!"

    Chick Corea
    (Electrik Band, Miles Davis, Return to Forever)
    Chick Corea
  • Adrian Belew and the Radial JDI
    Adrian Belew

    "Radial makes products no one else has thought to make and builds them better than anyone else can."

    Adrian Belew
    (King Crimson, Frank Zappa, David Bowie, Talking Heads, Peter Wolf, Paul Simon, Nine Inch Nails, Tori Amos, Cindy Lauper.)
    Adrian Belew
  • Radial JDI and Dave LaRue
    Dave LaRue

    "The Radial DI's have become a staple in my studio and in my live rig. The units sound great, and I love the versatility they afford me in any situation."

    Dave LaRue
    (Dixie Dregs, Joe Satriani)
    Dave LaRue
  • Radial JDI and Robert Scovill
    Radial JDI and Robert Scovill

    "The Radial products are the most transparent, technically comprehensive devices I have ever run across. They are right at the top of my list of 'gotta haves'."

    Robert Scovill
    (Tom Petty, Matchbox Twenty, Prince, Def Leppard, Rush)
    Robert Scovill
  • Radial JDI and Aaron Dessner
    Radial JDI and Aaron Dessner

    "The Radial J series DI's are easily the most reliable & consistent DI products available to the touring artist. Not only do they deliver a clean signal, they also seem to provide a unique warmth which is essential to The National's sound."

    Aaron Dessner
    (The National)
    Aaron Dessner
  • Radial JDI and Doug Wimbish
    Radial JDI and Doug Wimbish

    "Radial makes the most diverse DI's I have the pleasure of using. Connecting 20th century technology with 21st century reality. My Radial Duplex works great. No issues at all. No buzz or hum anywhere! Gold Star on the Forehead Radial!"

    Doug Wimbish
    (Living Color, Annie Lenox, Mick Jagger, Madonna)
    Doug Wimbish
  • Radial JDI and Ric'Key Pagiot
    Radial JDI and Ric'Key Pagiot

    "In the past I always found it hard to get a good warm piano sound in without being abrasive. With the JDI Duplex, I'm not afraid to push anymore when playing a piano patch. I like it!"

    Ric'Key Pageot
    (Madonna, Justin Timberlake, Timbaland, Musical Director - Cirque du Soleil)
    Ric'Key Pageot
  • Radial JDI and Alan Parsons
    Radial JDI and Alan Parsons

    "Our lives changed when we started carrying our own Radial DI's on the road. We use the ProDI, ProD2 and the JDI on bass. Our Radial Direct Boxes are rugged, reliable, and sound great - so much better than the competition - in fact there is no competition!"

    Alan Parsons
    (The Beatles, Pink Floyd, Al Stewart, Alan Parsons Project)
    Alan Parsons
  • Radial JDI and Otmaro Ruiz
    Radial JDI and Otmaro Ruiz

    "Not only do my keyboards sound cleaner and better than ever... but it makes me look super professional when the sound crew prefers to work with my Radial DIs instead of theirs!!...IT'S THE TRUTH!!!!!... I love their reaction!!!...LOL"

    Otmaro Ruiz
    (John McLaughlin, Frank Gambale, Steve Winwood, Gino Vanelli, Jon Anderson, Dave Weckl, Buny Brunnell, Alain Caron)
    Otmaro Ruiz
  • Radial JDI and Otmaro Ruiz
    Radial JDI and Otmaro Ruiz

    "I work for Steve Winwood in the studio and also out on the road. I have been using the Radial DI for a couple of years now - on stage and in the studio. I use it for the organ DI for both the studio and live use because it gives us the best tone."

    James Towler
    (FOH, Studio and Tour Manager - Steve Winwood)
    James Towler
  • Radial JDI and Joey DiFrancesco
    Radial JDI and Joey DiFrancesco

    "The Radial JDI is the cleanest, warmest and best (!!) I've found for plugging my organ in direct and is a great companion to mics on the rotary speakers."

    Joey DeFrancesco
    (Miles Davis, Jimmy Smith, Bobby Hutcherson, Elvin Jones, John McLaughlin)
    Joey DeFrancesco
Radial JDI Passive Direct Box

JDI™ Passive Direct Box

Part No. R800 1010

  • Jensen Transformer equipped passive DI
  • Eliminates hum and buzz from ground loops
  • Virtually zero phase & harmonic distortion
  • Exceptional signal handling and noise rejection

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 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 JDI delivers the natural, pure sound of the instrument without artifact.

The 100% passive circuitry inside the 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 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 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!

The Radial JDI… the world's finest passive direct box.

JDI Duplex

Stereo Direct Box


Rackmount Direct Box


Direct Box Rackmount Adaptors

JDI™ - Applications
Applying the Radial JDI with Electric Bass
JDI with Electric Bass
The JDI is often selected for high output bass guitars. It is able to handle huge signal levels without distortion or artifact. On stage it sends the pure sound of the bass to the PA with minimal loading. In studio, it is perfect for recording direct.

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Applying the Radial JDI with Acoustic Guitar
JDI with Acoustic Guitar
Most acoustic guitars have built-in preamps that can be peaky. The JDI naturally smoothes out the transients for a warmer tone. And because the JDI is able to handle huge transients, it will not distort. This makes the JDI a great direct box for acoustic guitars.
Applying the Radial JDI with Keyboards
JDI with Keyboards
Today's digital keyboards are not only very dynamic, some like digital pianos have a tremendously wide frequency response. The Radial JDI is able to withstand excessive signal levels at all frequencies without introducing distortion or phase shift.