Passive 2 channel DI for stereo keyboards with Jensen transformers


RRP $849.00




Radial has proclaimed the Duplex to be “the world’s finest passive stereo direct box” and we’re struggling to prove them wrong.

It’s basically a pair of their famously clear and dependable JDI passive DIs together in Radial’s traditionally bomb-proof housing.

Best used for stage keyboards – and when a great performer has spend $thousands getting their sounds right, years perfecting their craft and those magic moments are coming at your PA like a hurricane, you’d best make sure the signal chain is going to keep up.

Don’t choke the sound, let it fly.

For a more compact footprint (with a few less switches), check out JDI-STEREO

  • 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

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.

Specifications: DUPLEX
Audio circuit type: Passive, transformer based
Number of channels: Dual channel (stereo)
Frequency response: 20Hz ~ 20KHz (± 0.2dB)
Dynamic range: 135dB
Maximum input: +21dB @ 20Hz
Total harmonic distortion: 0.05% from 20Hz ~ 20kHz @-10dB
Phase deviation: 0.3° @ 100Hz; 3° @ 20Hz
Input impedance: 140k Ohms, unbalanced
Output impedance: 600 Ohms, balanced
Transformer: Eclipse ET-DB1, 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 input: +4dB balanced
XLR configuration: AES standard (pin-2 hot)
Connectors: 1/4″ in & thru, RCA in, XLR-F in, XLR-M out
Construction: 14 gauge steel chassis & outer shell
Finish: Baked enamel
Size  (W x H x D): 160mm x  48 x 127mm
Weight: 1kg
Power: Passive, no power required
Warranty: 3-year


“It rejects off-axis sounds brilliantly, so there’s no danger of other drums or instruments bleeding into the kick drum recordings. This saves a lot of time and effort during the EQ stage of the mixing process.”

Darren, Head of Technical Sales

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