I was looking for something to improve headphone sound and saw a review on the Audioengine D1 DAC. I had been plugging into the headphone plug on my speakers but that sound gets messy due to radio frequency interference from my router's wi-fi unit. The Audioengine is a tiny box with a loudness control that plugs into a USB port, it intercepts the digital signal that would go to the computer's sound unit, has its own DAC and a small amp that can drive headphones or a receiver.
This thing really cranks. It worked without any installation on my Mac, just plugged it in, went to System Preferences and picked Audioengine rather than the usual headphone output. Sonic detail, separation, general cleanness all drastically improved. It can take up to 24 bit depth, with a max sampling rate of 192 K, has a headphone jack as well as left and right stereo outputs. This is a fine little gadget.
