The Broadcast Tools Mix-4 is a four channel stereo audio utility mixer ideally suited for the typical broadcast studio or any similar applications. It features four stereo line level high Z mixing inputs, which accept balanced or unbalanced stereo sources. Each input is equipped with a high quality rotary level control and on/off switch with LED indicator. Input one may be configured as either a stereo line input or a microphone input with phantom power. The microphone input uses a high-performance pre-amp IC from THAT Corporation. Inputs one through four feed the balanced output, while inputs one, two, and three feed the balanced mono mix-minus output, which allows input four to accept audio from a telephone hybrid. Channel audio switching is done by professional level electronic analog switches. Each unit may be set on a desktop, mounted on a wall or rack-mounted with the optional RA-1 rack shelf for mounting up to three units in 1-RU.