If you are on a beer budget but not afraid to "tinker" check out this thread on the Valab. I've listened to the Valab stock (my own unit) and with the many modifications posted by contributor 'Bill Allen' whose own personal unit is incredibly better than stock. He is going to mod mine in the near future. I rarely use the term "giant-killer" but in this case it is absolutely correct.
http://www.head-fi.org/forums/f7/valab-nos-dac-subjective-listening-modifications-413540/
http://www.head-fi.org/forums/f7/valab-nos-dac-subjective-listening-modifications-413540/