iBasso D-Zero Mk2 Headphone AMP and USB DAC. The D-Zero is a minimalistic and sleek headphone amplifier and USB DAC. Housed within a beautiful and strong anodized aluminum housing, the unit is clearly made with passion and precision. The front of the device features a headphone jack, an aux jack, a power switch with white LED to let you know when the device is on, and a volume controller. On the back there's a USB output for charging the D-Zero and for connecting it to a computer, a gain switch and a USB charge switch. There's also two LEDs, a red one to indicate charging which also blinks to let you know when to charge it and an orange one to indicate USB connection. So buy this iBasso D-Zero Mk2 Headphone AMP and USB DAC Now £99.00.