Radial JDI

The Radial JDI is a premium passive direct box built around a Jensen isolation transformer, delivering exceptionally linear, distortion-free performance on stage and in the studio. It handles very high signal levels, eliminates ground loops, and adds versatile features like a merge function for summing stereo to mono, polarity reverse, and a speaker-level input option for taking a feed from a guitar amp. It’s a trusted choice for bass, keyboards, acoustic instruments, and more.

Highlights

• Jensen transformer for ultra-linear, low-distortion sound
• 100% isolation eliminates ground loops
• Merge function sums stereo sources to mono
• -15 dB input pad and -30 dB speaker-level pad with cabinet filter
• Polarity reverse and ground lift switches
• 14-gauge steel welded I-beam construction

Radial JDI: The Jensen Difference

Jensen transformers are prized for outstanding linearity across the frequency spectrum and the ability to handle extremely hot signals without saturating. In the JDI, that means a natural, uncolored sound from bass guitars, keyboards, and acoustic instruments, with virtually zero phase and harmonic distortion.

Versatile Input Panel

The 1/4-inch input and thru jacks let you feed both the PA and a stage amp. The merge function turns the thru jack into a second input to sum stereo keyboards or playback into mono, saving mixer channels, and a -15 dB pad accommodates hot line-level sources.

Setting Up the JDI

Connect your instrument to the input and, if needed, the thru jack to your amp. Run an XLR cable from the JDI output to your mixer or stage box. Engage the -15 dB pad for hot signals, the ground lift for hum, and polarity reverse when combining the DI with a mic on the same source.

What to Pair With the JDI

Pair the JDI with quality instrument and XLR cables, a mixer or stage box, and a Radial J48 active DI for low-output passive pickups.

Speaker-Level Input Option

With the -15 dB and -30 dB pads engaged together, the JDI can be connected in parallel with a guitar amp’s speaker to capture the amp’s distortion and tone. A built-in speaker emulation filter rolls off highs and lows to approximate the sound of a 12-inch driver.

Long Cable Runs

The balanced, isolated XLR output supports cable runs of up to 1,000 feet without appreciable noise, making the JDI ideal for large stages and installations.

Built Radial Tough

A welded 14-gauge I-beam inner frame makes it virtually impossible to torque the circuit board, preventing the cold solder joints that cause most DI failures. The book-end shell protects switches and connectors, and a no-slip rubber pad adds electrical isolation.

Passive vs. Active DI

Passive DIs like the JDI excel with active basses, keyboards, and line-level sources thanks to their noise rejection and huge headroom. Active DIs are often better for very low-output passive pickups.

Radial JDI FAQ

Does it need power? No. It’s fully passive.

Can I use it for stereo keyboards? Yes. The merge function sums stereo to mono at the output.

Radial JDI Specifications at a Glance

• Type: passive mono direct box
• Transformer: Jensen isolation transformer
• Input: 1/4-inch with thru/merge
• Output: balanced 600-ohm XLR (pin-2 hot)
• Controls: -15 dB pad, -30 dB speaker pad, polarity, ground lift
• Construction: 14-gauge steel I-beam

Who Buys the Radial JDI

• Bassists and keyboard players
• Touring and FOH engineers
• Recording studios
• Churches and rental companies

Why Buy the Radial JDI From Metro Sound & Lighting

Metro Sound & Lighting isn’t a catalog-only retailer. We design, install, and service sound systems in-house, so our team can help you build a quiet, reliable stage setup and support it after the sale. We offer B2B and integrator pricing for churches, schools, and venues.

Browse more options in our Direct Boxes category, or see the full specifications on the official Radial JDI product page.