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R800 2025
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The HDI is a studio-quality direct box designed to create exceptional recordings with any instrument, utilizing premium Jensen transformers and a unique Color control that provides an entirely new yet familiar-sounding sonic palette to experiment with.

  • Dial in an amazing tone within seconds
  • Blend from ultra-clean to amp-like distortion
  • Smooth Opto compressor for peak reduction
  • Mic and line-level outputs
  • Oversized custom-wound Jensen transformer

Instant Gratification

Despite the complex circuitry housed within the unit, the HDI has an elegant set of controls that allows the musician or engineer to dial up a record-ready sound with a minimal amount of tweaking required. The Level control drives the inputs of the HDI with instant visual feedback from the responsive front panel meter, while the Color knob provides seamless blending between an ultra-clean tone and amp-style distortion and saturation, so you can add just the right amount of character and grit to your instrument. A smooth Opto compressor can be engaged to control the peaks of the input signal, and a High-Pass Filter clears up any excessive low frequencies added by the Color control. Lastly, a Presence control accentuates the highs and high-mids, providing the ability to cut through the mix with results that are sure to impress.

Looks and Personality

With its gunmetal anodized 1/4" thick milled front panel and distinctive styling reminiscent of classic outboard studio equipment, the HDI is sure to turn heads in any recording space. A custom output meter provides a level check at a glance, with oversized chrome knobs for precise adjustments and easy tweaking on-the-fly. The HDI is a stunning standalone unit, but it also comes complete with mounting hardware to install in standard 19" equipment racks. One or two HDI's can be installed side-by-side in a 2RU rack space, and like all Radial products, they are built with rugged components and designed to easily withstand the rigors of concert touring.

Behind the Design

While the HDI is incredibly easy to use - requiring only a few seconds to achieve great-sounding results - both the design philosophy and the under-the-hood processes at work are anything but simple. Click here to read an interview with the HDI's designer, W.C. "Hutch" Hutchison for an in-depth look at how the HDI came to be and what makes its circuitry so unique.

Technical Specifications

Frequency response: Line Output: 1Hz ~ 100kHz +0.25/-3dB, 20Hz ~ 20kHz +/-0.1dB Mic Output: 1Hz ~ 100kHz +0.25/-3dB, 20Hz ~ 20kHz +/-0.1dB
Dynamic range: 112dB (20-20k, unweighted, referred to +25dBu)
Gain: Min Gain (Level CCW): -3dB Max Gain (Level CW): +31dB
Total harmonic distortion: 0.3% @20Hz, 0.22% @100Hz, 0.01% @1kHz (+4dBu In)
Signal to Noise: 91dB (20-20k, unweighted, referred to +4dBu)
Maximum Input: 1/4" TS: +5dBu, 3 VAC RMS, 8.4 V Peak to Peak 3.5mm: +25dBu, 7 VAC RMS, 20V Peak to Peak (Level @ 12:00)
Maximum Output: Line Level XLR: +25dBu (1% THD at 1kHz) Mic Level XLR: +3.7dBu (1% THD at 1kHz) 1/4" Processed Out: +8dBu (Approx. unity gain with Level @ 12:00)
Input pad, Ground lift, HPF
Input Connectors: 1/4” TS (front and rear), 3.5mm Synth
Output Connectors: XLR Line / Mic, 1/4” TS Processed, 1/4” TS Thru
Extras: Opto Compresser: 6:1 ratio, max 8dB gain reduction HPF: 40Hz / 100Hz rolloff @ -6dB/octave
Construction: 14 gauge steel chassis, 1/2” aluminum front panel
Size (L x W x D): 8.25” x 8.25” x 3.5”
Weight: 5.05lbs
Power: 100-200VAC 0.45A ~ 50/60Hz
Conditions: For use in dry locations only between 5°C and 40°C

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