Versatile single rack space four-channel headphone mixer/amplifier that is loaded with advanced features that provide tremendous flexibility for monitor and cue mixing. The master input features an input level and LED meter to control and display the overall stereo input. Each of the four channels includes three headphone outputs with an overall volume control and individual 8-segment level meters. A convenient stereo auxiliary input is available on each channel so that individual line signals from direct or buss outputs can be mixed with the main stereo input. The balance control adjusts the ratio of the main and auxiliary signal or the left to right balance (based on the setting of the ST/2CH switch) so that each headphone mix can be further tailored for a particular listener's individual needs. For greater sonic control, the amplifier also features a 2-band equalizer on each of the four channels. A master stereo aux input on the front panel is also supplied for inserting a second signal to all headphones.