I recently bought a preloved NDX (2012) replacing nd5xs (2014). I play music from my NAS and streaming with Tidal. Before I let the nd5xs go, I had to compare the two against eachother, with and without powersupply (xp5xs). I thought it would be interesting sharing my findings on the forum. The other components used are listed in my profile.
Starting of with the bare nd5xs it delievers a good soundstage with separation of the sound. Very lively and musical experience. I then added the powersupply adding a slightly bigger soundstage, more of a subtle improvment overall. Very nice and I really enjoyed this combo the last couple of years.
I then connected the bare NDX, expecting it to be slightly better than the nd5xs and PS. But I was surprised - the NDX outperforms the former combo. I would say that the biggest improvments are the bigger soundstage, separation of instruments and control. My biggest update so far. Wonderful!
Adding the xp5xs to NDX added a little bit of refinement allover the spectra.
I used to believe that the nd5xs with xp5xs could match the bare NDX. To my ears thats certainly not the case. NDX is in many aspects a better streamer.
Hope this is helpful for someone else!