My reference DAC has been and still is the Peter Daniel NOS non-filtered Phillips TDA1543 based USB DAC. It is hand made in Canada and built like an Omega speaker. It follows the 47 Lab way of thinking. It's sound is analog, warm and full, 3 dimensional, detailed, with a lot of weight. It works well with any Omega or Hoyt Bedford, new and old. I have run it with SET, PP, gain clone, discrete A/B, and MOSFET, all with great results.
Running a second to the Peter Daniel and about half the price, is the KingRex UD01 USB DAC with PSU MKII and XLR power connection. If I wanted T-Bone steak sound on a hamburger budget, this is what I would seriously consider.
Some people may think I am a member of the flat earth society but no DACs I have heard (or even CD players) do 16/44 (which makes up about 95% of digital music available today) like these DACs.
Almost all my impressions of these DACs have been through highly resolved systems using Omega or Hoyt-Bedford Speakers.
My music players are iTunes and Pure Music on a MacBook that is configured for playing music and nothing else.