The HPA-4 with talkback/cue, powers up to four sets of headphones. Each output is supplied with a hefty stereo amplifier and may be configured to accept talkback/cue audio on the left headphone with a simple contact closure to ground. Front and rear panel T/R/S jacks are provided with each output, along with front panel level controls. The stereo balanced input is adjustable with the front panel master level control, while the balanced monaural talkback input is equipped with a rear panel trimmer. Additional features include power, talkback/cue active and program audio activity front panel LED indicators, and surge protected internal bi-polar 15-vdc-power supply affording superior headroom and high definition audio. The HPA-4 is equipped with two power jacks allowing one wall transformer to power two units. The half rack profile allows the unit to be set on a desktop, mounted on a wall or as part of the new RA-1, Rack-Able mounting shelf.