FiiO E9 Desktop Headphone Amplifier and Dock for E7 USB DAC Two channel power output, with jacks for both 1/8(3.5mm) and 1/4(6.35mm) headphones TI TPA6120 current feedback power amp with low noise, low distortion and high switching rate Soft on/off with sealed relay protects power amplifier output Smooth and low noise ALPS sealed potentiometer for volume control Audio buffers using ultra-low distortion and low noise Burr-Brown OPA2134 op amps