"i have a NAD D1050 which is now 5 years old but still sounds fantastic."
Relative to what other DACs you’ve heard???
"what has happen in the last 5 years? have their really been such great strides in digital playback made? i think SS is evolving faster"
Um, no. Not even close. SS has been dead in the water relative to what’s been happening in digital-to-analog conversion IMHO. There have been very exciting new entrants into the DAC realm over the past 5 years that offer very different approaches to converting digital data to analog. If you haven’t listened to the latest R2R, NOS, etc. DACs from the likes of Schiit, Mytek, Metrum, Chord, etc., you need to do some listening. Whether it’s through the Chord approach of refining filters or the Metrum approach of improving the non-upsampling path, there has been a bit of a revolution that has recognized and is looking to surpass the limitations and artifacts of the "delta sigma" era that your NAD DAC and many others were a part of.
I’m gonna make my own pedestrian and oversimplified observation of what’s going on in today’s DAC world that hopefully translates and is roughly analogous to the tube vs. solid state debate that’s been going on for over 40 years.
I think the purveyors of the NOS/non-upsampling faith are analogous to the tube pres and amps of today in the analog world. This camp is striving to preserve the essence of the initial analog waveform in the digital world and transfer as much of that analog-ness as possible into the listening experience with as little processing possible. On the other hand, there’s the digital side that is trying to take every electronic bit available and best interpolate all those captured bits into the best analog waveform possible with as few as possible digital artifacts. In short, one camp is trying to preserve the best of analog and preserve it into the digital world, while the other is trying to capture the advantage of every last digital bit and use it to enhance the analog listening experience. Both are laudable and valid approaches IMHO, and to be perfectly honest, at this point I’m agnostic and haven’t planted my flag in either camp. But I’m vigorously rooting for both!
So, here’s my ultimate analogy and observation for you: Both of these digital camps have realized that the "old school" delta-sigma DAC process (of which your NAD DAC is one) is compromised or at least not completely natural sounding to most audiophiles. But, as with the best of solid state and tubed amplifiers and preamps, as both sides improve they are starting to sound more and more alike at their pinnacles.
So, the short answer to your question from my perspective is this -- your DAC, while maybe good for its time and price, has been left in the proverbial digital dust. Your main question now should be, should I go NOS (tube-like) or upsampling (solid state-like). And, maybe not coincidentally, the trade-offs seem to be right along the same traditional party lines as solid state versus tubes in our current industry -- and both converging as we speak. Maybe, as with our political parties, it will and should always be thus to get the best end result for the people.
