Radial Engineering is shipping its HDI, a high-definition studio-grade direct box and preamp for studio recording or live-touring applications.

The cornerstone of the HDI’s capabilities is the color control, which allows the blending of the signal from an ultra-clean operation on one side to amp-like distortion and warm transformer saturation on the other. The results are both musical and versatile, allowing the HDI to shine when used on bass, acoustic guitar and even keyboards.

The color control is complemented by level and presence controls, each featuring extra-large chrome knobs for precise adjustment. The level control allows the HDI to accommodate a wide range of input sources, while also providing the means to drive the internal circuitry harder for more exaggerated coloration. The presence control offers an emphasis on the high and high-mid frequencies, to dial in enough bite for the signal to cut through a mix.

Aside from the three main controls, the HDI also includes a Hi-Z switch that approximates the Hi 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 three-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 on front and rear panel ¼” jacks along with a Thru connection for an amplifier. A 3.5-mm mono Synth Input is included for 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 faceplate 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.