The Sound Devices HX3 is a portable stereo headphone amplifier for critical audio monitoring. This headphone amplifier is ideal for adding headphone feeds for portable and studio applications. The Sound Devices HX3 provides three independent audio feeds from balanced and unbalanced, line level sources. Each headphone output has its own level control, peak LED and 1/4" output connector. With extended bandwidth and high drive capability the ​Sound Devices HX3 can drive headphones of various imepedances to high levels with very low distortion - key to monitoring in high SPL environments. It is powered by two AA batteries or external DC.