New Radial HDI – Now Shipping

May 12th, 2020

Radial Engineering is pleased to announce that the HDI, a high definition studio-grade direct box and preamp for studio recording or live touring applications is now shipping.

Make any instrument sound great

The HDI is Radial’s flagship direct box, featuring a striking design aesthetic along with a unique and powerful feature set that will provide outstanding results with any instrument.


Behind the Design

Created by legendary design engineer “Hutch” Hutchison, the HDI utilizes guitar amp topology and industry-leading Jensen transformers to elicit vintage warmth and richness. Four parallel circuits are employed within the HDI, yet this complexity is balanced by a streamlined and elegant feature set that produces immediate results.

On the design philosophy behind the product, Hutch explains
“The HDI goes beyond the basic utility and functionality of a direct box, while maintaining the essence of a DI. I wanted to create something that was more creative, fun, inspiring and musical.”

Aside from the three main controls, the HDI also includes a Hi-Z switch that approximates the H
i and Lo inputs on a vintage amplifier, and a single-control Opto compressor which allows for smooth and natural peak reduction of the input signal. A 3-position high-pass filter rolls off any excessive low end created when pushing the HDI into distortion, and a ground lift switch rounds out the front panel controls and helps eliminate any hum and buzz that might be present.

Inputs for the HDI are provided on front and rear panel ¼” jacks along with a Thru connection for an amplifier. A 3.5mm mono Synth Input is included for easy connection to modular synthesizers. Transformer-isolated mic and line-level XLR outputs are provided for direct connection to mic preamps and recording interfaces, along with a ¼” Processed Output for feeding the affected signal to a guitar amp or instrument effects units.


The HDI features a ¼” milled gunmetal-anodized face plate that will turn heads in any studio as a standalone piece. The unit also ships with an included rack mounting kit for installation in a 2RU rack space, and can be mounted side-by-side with a second HDI for stereo applications.

Using the HDI with an amplifier
Record bass directly from the HDI while also feeding the unbuffered Thru output to a mic’d up amplifier to blend the two signals together. The HDI sounds so good on its own you just might mute the amp track altogether.


Using the HDI on acoustic guitar
The HDI pairs well with any instrument – with acoustic guitar it can add additional body and character that other direct boxes may lack. Take the line-level XLR output directly to your recording interface to bypass the need for any additional preamps in the signal path.

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