My experience...
Cables make a huge difference for sure.
External clockers make a huge difference.
Jitter is the plague of digital audio. It can come from transports and servers. There are devices that go in the audio path to clean it up.
How do I know all this? I use my ears.
Not to discount your experience or your ears, but I have tried all manner of these devices and find they make no difference .. in my system.... to me.. I have tried among others
- Uptone USB regen
- Uptone EtherRegen
- Cisco 2960 switch modified with a TCXO oscillator
- Mutec MC-3+ USB reclocker with Mutec Ref 10
- Roon Nucleus server
- Innous Zenith server
- Small Green Computer i5
- various Mac Minis (which I currently use with the the Uptone linear DC/fan control mod)
- Innous Phoenix USB reclocker
- various USB cables
Of course I can’t say for sure why. It may be that I have wooden ears, or the fact that I use a pro audio DAC that has a very high quality clock built in that is also locked to a very high quality external 10MHz reference clock. The DAC is also a re-clocker that has outputs for both a high quality word clock and a de-jittered data stream if needed. .. but at the end of the day, just like you, my ears tell me what is important to me.
As for jitter from servers and transports.. Asynchronous transfer is designed to eliminate that. The DAC asks for data packets at its pace and clocks them on down the line using its internal clocks. Any jitter from the source is therefore disregarded so if you hear a difference using devices as above, in theory it is not because they reduced jitter. That said, I don’t doubt you hear something. I’m just saying that attributing it to jitter flies in the face of everything we know about how this stuff all works. I’m also pretty sure we don’t really understand how all of this stuff works, nor do we really need to if we are getting the results we want.
It would be interesting to use a source to feed an asynchronous DAC where you could vary the jitter and determine if you could hear it.