Radial JDI MK3 Passive Direct Box

- 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

- Transformer: Jensen JT-DBE, 12:1 ratio
- Shield: Dual Faraday, mu-metal can
- Input pad: -15dB
- Merge: Sums left & right sources to mono
- 180* 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" in & thru, XLR-M out

- Construction: 14 gauge steel chassis & outer shell
- Finish: Baked enamel
- Size: (W x H x D) 84 x 127 x 48mm (3.3" x 5.0" x 2")
- Weight: 0.70 kg (1.55 lbs)
- Shipping Size: W x H x D: 102 x 76 x 165mm (4" x 3" x 6.5")
- Shipping Weight: .87 kg (1.92 lbs)
- Power: Passive, no power required
- Warranty: Radial 3-year, transferable
Dimensions and Weight in Packaging
Base Item
Shipping Weight: 1.75 lbs
Shipping Dimensions: 7 x 4 x 3 in
Manufacturer Part Number (MPN): R800 1010
If you have additional warranty questions, please contact the manufacturer at 604-942-1001

Radial JDI mk3 Passive Direct Box

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 1/4" 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 mu-metal 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.


- Jensen Transformer equipped passive DI
- Eliminates hum and buzz from ground loops
- Virtually zero phase & harmonic distortion
- Exceptional signal handling and noise rejection
(25 ratings)
Submitted March 24, 2008 by a customer from gmail.com
"Stop searching... your DI troubles are solved."
The search is over.
I used this on my 6 string bass... WOW! I was having a bit of a hate on for the bass as I felt it was a bit lack luster going through my other passive DI box. This was different... no lie my B string sounded tighter, and the pups on the bass sounded clearer. I will not let this DI box go - EVER!
There's a number of cool things it can do... but I'm just DI'ing it no need yet for the other bits...
Ease of Use
plug-n-play not pray
TANKS should be built this well...
I'd pay more but I'm glad I didn't have to.
Manufacturer Support
They're Canadian... so polite.
The Wow Factor
I want the JDI rack for my synths now
Musical Background:
Recording Engineer
Musical Style:
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