The Ampex MX-10 is a 4x2 mic / line mixer. In stock configuration, all four inputs accept microphone level signals and inputs 3/4 can also accept line signals. With a relatively simple modification, the first two inputs can also accommodate line signals. Direct outputs and transformer-balanced main outputs are other common modifications.

A three-position switch for Left/Center/Right panning is available per channel. Each channel and the master stereo output have their own level controls.

The circuit is based around a Beyerdynamic input transformer, EF86 tubes running as triodes, and a 12AU7 in a cathode follower design.