The Black Cube Linear is a small, slender box with your choice of silver or black faceplace and knobs. It measures 11"L x 4 3/8"W x 1 3/4"H and weighs 3.3 pounds. These dimensions illustrate perhaps why Lehmann Audio named it the Black Cube Linear. The unit’s small cross-section makes it easy to place on a shelf beside another component. Unlike many other headphone amps, this one will seldom require a separate shelf.
The Black Cube Linear's power supply is built in; there is an IEC connector in the rear, so you can pick a power cord that sounds good to you. Next to the IEC connector are the on/off switch and two pairs of gold-plated, Teflon-insulated RCA jacks: an input and an output pair. You can, therefore, feed the signal through the Black Cube Linear and use the front-mounted volume control to adjust the line-level-output volume as well as the headphone volume, making the Black Cube Linear a single-input line-stage preamp as well as a headphone amp. The volume control knob has a little dimple on the front, so you can tell how far its turned up, although on the black unit I auditioned, it was hard to see the dimple. Maybe a little white paint (or even an LED) in the dimple would make sense. The front panel holds two 1/4" Neutrik gold-plated headphone jacks.