Digital source sound quality is primarily affected by jitter, including USB and Ethernet interfaces.
D/A’s are primarily affected by digital filtering and internal/external power delivery.
Jitter will affect the imaging, focus and dynamics
Digital filtering will affect the liveness and airiness factor
Poor power delivery will make the bass flabby or thin and impact the dynamics
If you are using a digital source and are relying on the D/A in all of these devices, then you will have widely varying results because you will have both of these effects. In most cases, you will get high jitter combined with undesirable digital filtering or poor power delivery.
The best way to optimize is to use a digital source with really low jitter, like 10psec, directly measured to start with. Then add a really accurate, low loss digital cable between 1.25 and 2 meters in length. Then select a DAC that sounds live to you. The interface on the DAC is critical, even more critical than the D/A portion. USB interfaces often have high jitter, but are also plagued with other limiters like the playback software and USB port quality. Ethernet interfaces are easier for the user to optimize and less reliant on the computer hardware although the playback software still matters as well as the cabling from the router/switch. I have personally moved from USB to Ethernet, but I still use a USB interface for streaming Amazon music and for sampling tracks from HDtracks etc..
Finally, I recommend powering the source and the DAC from a Plasmatron AC voltage regulator. This is the ONLY AC device that works well for digital IME.
Good luck finding a source with low jitter. Most manufacturers don’t publish their jitter specs or don’t bother to measure it. Most manufacturers are not capable of designing low-jitter gear either. It takes expensive equipment to make this direct measurement accurately, like $150K expensive. Here are some direct measurements of jitter I have made:
https://www.audiocircle.com/index.php?topic=157348.0
https://www.audiocircle.com/index.php?topic=154425.0
https://www.audiocircle.com/index.php?topic=154310.0
https://www.audiocircle.com/index.php?topic=154408.0
Jitter of the Sonos is reduced by a factor of 1000.
Steve N.
Empirical Audio