A warm low-ish cost DAC is the Gustard X26 Pro. I owned it for a while and loved it.
I also owned the AudioMirror (top model). It was pretty good but I preferred the Gustard for my warm DAC types.
I currently own the Benchmark DAC3B. It just does the job and I like having it around. It is a little hot on top. I was told by someone with some audio experience that the DAC3B is a little shy on the bass and that makes the top seem hotter.
The best DAC I own is the Musetec 005, ($2965 - $3300). It has the perfect warmth, detail, and really dense sound. I would like to get a second 005 to replace the rather good Topping D90SE DAC in my living room system.