@jjss49
this does raise the question of the wisdom of buying an expensive unit where one part (the DAC) might become outdated before other parts (linestage and amplifier) -- such is the challenge of figuring out how to spend money wisely in high end equipment... no clear answer
I’ve seen this line of thinking over the years. Personally, I believe about five - ten years ago the better digital converters began to sound like music. I agree that a bad dac permanently installed in a good amp isnt ideal but in most cases you arent prohibited from adding an external dac.
Here’s where I see the flaw in the argument. If you think something sounds good today, then it sounds good. Dacs dont erode over time like a tube, they will within operating parameters always sound as good as when you originally chose it for apparent sound quality reasons. To fully reveal my biases, Im not convinced that the ever increasing bit rates and dxdsdxyz mega resolution of month is improving the musical reproduction but YMMV. The better ladders/R2R dacs seem to be extracting the best of the format to my ears. Improved renderers/transports appear to have been a revelation in recent years.
i have two digital setups that I really enjoy both fed over ethernet by an Innuos Zenith mkIII. In one setup, the Aqua La Scala/Linq is very nice and in anothe the inboard dac in my Boulder 866. They sound different but equally musical and I feel Im leaving nothing on the table. In fact, the dac in the 866 is good enough that Boulder is launching a new preamp in the 800 series based on the dac found in the 866. It features analog inputs, digital inputs and a sophisticated headphone section.
How good is the output stage, thats where most of us should focus. In short, if it sounds good to you, it is good. My 2 cents.