The NuForce DAC9 isn't the only DAC to include a headphone output, but it makes more of a point of it than most, and fair enough, adding as it does a dedicated volume control and both flavours of headphone jack, 6.3mm (quarter-inch) and 3.5mm. The latter, incidentally, also functions as an input, an optical digital input to be precise, in similar manner to some computer sound cards and portable audio devices.



Link: Techradar