If you want a DIY DAC a good choice is the Rakk Dac from K&K Audio. I am currently using one with a Musica with Great results. http://www.kandkaudio.com/
I am also using one with the DEQX 2.6p which is a little more than a DAC but I am getting good results from it as well.
I am also using one with the DEQX 2.6p which is a little more than a DAC but I am getting good results from it as well.