As important as a DAC is in the chain thru the Wadia 170i, the coax cable election is also critical - I ended up spending more in this part than in the Wadia, but it paid for itself.
The custom coaxial cable that comes with the Wadia unit is crap, I tried at least a dozen from Audioquest to Kimber to SIltech, and found peace with an HT10 G5 Siltech. Using this combination (Wadia 170i-Siltech HT10 and Reimyo DAC) I do not miss my Reimyo CDP777 at all.
Hope this helps,