Asus Xonar Essence One Muese edition - MUSES 01 Op-Amps with oxygen-free copper interconnects , ASD ( Advanced Symmetry Die-bonding ) Technology , USB digital-to-analog converter , 8x symmetrical upsampling and 120dB SNR , built-in 600ohms headphone amp , balanced XLR output , 2x dedicated volume control knobs for speaker + headphone , 24bit 192KHz , analog + optical + toslink digital input