Hi Bill,
I absolute agree your opinion about DigiOne, perfect S/PDIF player! In my case it goes via
DigiOne -> Chord 2Qute -> Lehmannaudio Linear -> Sennheisser HD800S … sounds very harmonic !
But anyway, I think last weekend I did again a little improvement on my system. I was never happy that the Rasperry Pi is getting the power via a (shit) Mini-USB connector. So I soldered the power of my 5V Sbooster direct on the back of the Raspberry Pi:
- 5V direct on two pins of GPIO connector
- GND on “a lot of USB grounds”
Wow … sounds better and so far I never had a flashing red power LED again on the Raspberry Pi. Try it, it’s only “a 35 Euro risk” 
… Regards Tom