Apogee GROOVE Portable USB DAC and Headphone Amplifier for Mac and PC USB 2.0 connection to Mac and PC with up to 24 bit / 192kHz audio Enhances your iTunes, Tidal, Spotify, Pandora or other music listening experiences Constant Current Drive provides smooth frequency response with any headphones Quad Sum DAC , 4 DACs per channel for highest dynamic range and lowest distortion Premium aluminum build quality, Built in the USA