The Superlux HA3D is a portable, stereo headphone amplifier designed for demanding and critical audio monitoring. This audiophile-quality headphone amp is ideal for adding headphone feeds for portable, studio, and audio enthusiast applications.The HA3D provides 3 independent headphone feeds from balanced or unbalanced line sources. Each headphone output is controlled by the associated level control, equipped with independent peak LED, and 1/4-inch output connector. With its extended bandwidth and high current/voltage drive capability the HA3D can drive headphones of various impedances to high levels with very low distortion, important for monitoring in high SPL environments. It can be powered from two-AA batteries or external DC.