Hello, I think a good place to start looking is with the Bel Canto DAC 1 and 1.1, which can be found on Audiogon for $400-$600 used. I enjoyed a DAC 1.1 for 9 months and only improved on it by upgrading to a unit that cost much more.
It has a detailed yet smooth presentation, and the small chassis makes it easy to place on your rack. The compactness and lightweight can be a drawback if you use thick, stiff cables. Nothing funnier than seeing it floating in air while connected to a thick digital garden hose. I got good results using the Bel Canto with Kimber Illuminations D60 which is thin and easy to manage.
It has a detailed yet smooth presentation, and the small chassis makes it easy to place on your rack. The compactness and lightweight can be a drawback if you use thick, stiff cables. Nothing funnier than seeing it floating in air while connected to a thick digital garden hose. I got good results using the Bel Canto with Kimber Illuminations D60 which is thin and easy to manage.