I am palling to upgrade my current digital audio system. I use popcorn c-200 + Rega Dac + Naim Nait XS and want to purchase Olive 4HD as main source of my digital music. The question which I have is how good the built in Dac of Olive 4HD is ? Should I use Olive 4HD alone ( as source and Dac ) or I need to hook the Olive in the Raga Dac ? Which one will give me better quality - Olive 4HD alone or Olive HD + Rega Dac ?