OPPO HA-1 Headphone Amplifier / DAC / Stereo Pre-amplifier (Black) Discrete Class A balanced headphone amplifier - fully balanced analog inputs and outputs, purely analog volume control, and two adjustable headphone gain settings ESS Technology Sabre32 9018 Reference DAC; Asynchronous USB DAC up to 384 kHz 32-bit PCM and DSD256 Pre-amplifier with stereo XLR and RCA inputs and outputs. Per-input Display driven interface - Front panel LCD with selectable spectrum and VU meter displays, physical volume & source selection knobs Mobile device support - certified for iPod/iPhone/iPad and Bluetooth audio with high quality AptX codec