Melco Audiophile NAS

[simoncn]

The switch does have an impact because it creates noise and some of that noise travels down the LAN connection to the Melco.

You can reduce this noise by setting a static IP address for the Melco. This stops some network traffic that is required when in DHCP mode. There will still be network traffic to the control point when a song is playing (usually one interaction per second). If DHCP is disabled, you can unplug the network connection from the switch to the Melco as a test to see whether stopping these interactions with the control point improves the sound.