Ethernet Cables, do they make a difference?

If one thinks noise is an issue, they can and should test for that. Whether they think the problem is noise getting inside the ethernet cable or the noise getting out of the ethernet cable.

I personally haven't found noise as discussed above, to be a problem in my setup with my Bryston BDP-1. I use an 18 feet AES cable so I can move the BDP-1 far away from my rack so no ethernet cable goes near the rest of the components. I don't notice a difference when the BDP-1 and the ethernet cable is in the rack or far away. In fact, I've tried piling 100 feet of Cat6 UTP on my DAC and interconnects, and noticed no difference in sound. I suppose my interconnects and gear is well shielded. It very well may make a difference in other people's setup.

Similarly, I can play music off a USB flash drive, and use the ethernet connection for only interface control. I don't notice a difference in sound by the plugging and unplugging of the ethernet cable. If there is noise present, the unplugging of the cable should make it better.

However, I do find a difference when streaming through Roon based on the length of the ethernet cable or the device/power supply used. Based on my experiments, I haven't been able to find conducted and radiated noise as an issue. Aside from shielded and grounded ethernet cables which are breaking the isolation, I suspect in a calm home environment, the differences in sound may be with how the signal is dealing with the PHY. Signal integrity could be at play here.

It's hard to conclude anything without measurements, but still there are tests that people can do at home to test out various hypothesis.

@zoom25 good explanation is here: https://www.stereophile.com/content/bryston-bdp-1-digital-audio-player

If player and DAC are separated Ethernet cable should have no influence

Hello @acepilot71,

I'm not sure what you are referring to specifically (what page/section) in that review?

I use Roon and connect my BDP-1 via ethernet which further feeds my DAC.

When I use the BDP-1's native MPD software and play music off a directly connected flash drive, it doesn't make any difference to the SQ whether an ethernet cable is plugged into the BDP-1 or not. It doesn't care what devices are used. In this setup, the ethernet is there only for controlling playback.

However, when using Roon with the same setup, suddenly all these subtle differences start appearing based on the device, power supply, or ethernet cable (length) used.

I'm not sure why this is the case .I have done a number of experiments to try and isolate variables and see if any patterns emerge. Some of the results make sense with the established knowledge, while other results go against what most audiophiles are doing and assuming as the culprit.

I meant that DAC is well separated from played - that is the key.
Actually cable from  BDP-1 to DAC may create some difference.

Try toslink from BDP-1 to DAC

The BDP-1 doesn't have a toslink output...

I'm not sure if we're both on the same page about what we're discussing.