A Bluesound representative told me the least expensive upgrade to the Node X was replacing the stock power cord. I hooked up a Transparent Audio Hardwired C7 power cord and was very happy with the changes. I am currently running coax out to my Moon DAC and I am pleased.
Difference between Bluesound Node, Node 2, Node 2i, NodeX
Audiogoners.
I love the Bluesound user interface Is the only difference between the different Node models the DAC portion?
Which would indicate that if you use coax out to an external DAC all Node models would sound the same through the speakers.