Have been all digital this last 15 years, and my current thinking is that for digital, unlike many of the views expressed earlier, everything mattters.
Simplisticly put, instead of a continuous stream (analog) the music is chopped up (sampled) and then recombined to simulate the original analog stream. Theoretically, since the sampling is so quick, the ear cannot detect the difference. What the ear does detect, however, are the inaccuracies in the process. That is jitter. Reducing jitter is what it's about.
The recompiling is timed by a clock which emits a 'ping' every fraction of a second. This ping corresponds to a marker embedded during the sampling process in the signal. The more this is in sync, the less jitter, the purer the signal.
So all digital devices have a 'clock'. The better the clock the better your music will sound. But like everything, there is no magic bullet here. If you feed in garbage, even though the very good quality clock you might have struggles valiantly, it can improve the signal only partially. So you have to clean up the signal as much as possible before it hits the final clock prior to conversion back to analog.
This means digital devices need much of the same treatment as analog:
Good powerGood components
Good component support/footersGood cabling
Hopefully, this argument has indicated that timing (reduced jitter) is all important in digital systems.
And finally, here is the good news for those of you who have managed to get through all of the above: After all this, you can STILL get the signal reclocked and cleaned up hugely by a relatively new device...the audiophile switch. The reclocking in them is far more accurate than the clock in most DAC's. They work even better in a cascade (series) as each stage cleans up the signal more. Price for these switches vary from usd 700/- to many thousands.
My system comprises router/NAS > streamer > dac with 3 audiophile switches in series prior to the streamer. The addition of each streamer marked an large order of improvement.
Most audiophile switches come with the capability of using fibre optic (which can be immune to electrical effects) instead of copper wire, but that's another story.
So, once you got the basics sorted, i.e. storage device, streamer and dac, to get to serious high end sound you should clean up the signal more with audiophile switches. This will help no matter how high end the clock in your final digital component, the dac, is.
The never ending story here is using external clocks! These are accurate to atomic standards and there is a whole cult built up around implementing them. My first one arrives in a couple of weeks!
Best wishes, and hope this diatribe has been of use. I have avoided talking about branded components to avoid the appearance of shilling. My 2 cents.
