Mapman, upon reading your post, I saw a CD player I never heard, or read a review of, the Constantine. So, I looked it up and found this lovely review of it, and another similar DAC. My DAC has four tubes. There will always be arguments on the worth of tubes. All I care is if the resulting music strikes me as being authentic.
http://www.enjoythemusic.com/magazine/equipment/0406/mhdt_laboratory_dac.htm
http://www.enjoythemusic.com/magazine/equipment/0406/mhdt_laboratory_dac.htm