High Definition Studio Preamp

The HDI is a studio-quality preamp 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.

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.

HDI Applications Using the HDI alongside 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 gain stages in the signal path.

Using the HDI Processed Output

The HDI can feed processed signals to your amplifiers at the same time as you feed the inputs of a mixer or audio interface. This allows you to provide additional gain, saturation, and distortion to the inputs of a clean amp or an amp modeling system.

Using the HDI with modular synthesizers

A dedicated Synth Input has a lower sensitivity to accommodate the hot outputs of modular synths or even other studio outboard equipment, allowing you to use the HDI to process any instruments or tracks you can think of.

Specifications Specifications Frequency response: Line Output: 1Hz ~ 100kHz +0.25/-3dB, 20Hz ~ 20kHz +/-0.1dB Mic Output: 10Hz ~ 80kHz +0.25dB/-3dB 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) Features 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: Output pad, Opto Compresser: 6:1 ratio, max 8dB gain reduction HPF: 40Hz / 100Hz rolloff @ -6dB/octave General 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 Warranty: 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.