The D1 comes with a nice microfibre bag for transporting the unit as well as short, a gold-plated USB cable (for what it’s worth). There are no bass or treble controls, the sound seems to be a nice flat frequency response and the DAC adds no colouration to the sound. Sound quality is very good – I’m of the opinion that a well-made amplifier should be a straight wire with gain, and this amp seems to do the job. Sending the RCA output to my Audioengine A2‘s delivers clear sound and, at least through these speakers, I can’t hear anything negative about the sound it delivers. It seems that it will be able to drive difficult headphones with no problems – my Sennheiser Momentums (which are a low-impedance headphone) only need a small amount of volume on the dial to achieve a comfortable listening volume.

Plugging in headphones mutes the RCA output and directs the audio to the headphones. With no headphones plugged in, audio is output to the stereo RCAs on the rear. On the front of the unit is a rotary volume dial (with smooth rotation, no clicks or indentations), the power button with a white LED power indicator and a 3.5mm headphone jack. There’s also an optical input as well as a pair of gold-plated stereo RCA plugs for output. If you’re using the optical input, then you need a USB power adapter to provide power to the unit, however if you’re using USB to connect to your computer, then it uses the power supplied over the USB bus. It doesn’t need drivers on OS X (confirmed) or Windows (not tested by me) – immediately after plugging it in, a new audio output source is available called Audioengine D1. It’s got a USB input on the rear, which also supplies data and power to the unit. It’s a pretty simple and minimal DAC with good sound quality.

Audioengine d1 dac sound problems