The Henry Engineering Matchbox HD is a professional grade analog level and impedance converter, serving as an interface between consumer and professional audio equipment.

The Matchbox HD is a bi-directional unit, employing four independent amplifiers to convert stereo inputs and outputs from unbalanced -10 dBv levels to +4 dBm balanced 600 ohm lines. All four outputs are adjustable, accomodating a wide variety of operating levels.

The Matchbox HD also features a HI GAIN mode to properly match the low-level unbalanced outputs of computer sound cards. The unit's direct-coupled circuitry, and wide dynamic range, provides the sonic transparency, fidelity and level required by the digital editors, DAT's, Hard Disk, Flash Card recorders, and other digital audio sources with which it is meant to interface. The unit has an internal power supply, and 3 units may be rackmounted in a single rack tray, or individually wall and cabinet mounted.