Is it worth it? DAC question

Yes!!!

There is no HDMI input to the Zen DAC that I can see so not sure what you’re talking about here.  You need to run a USB cable between the Node and the Zen DAC. 

Seems incompatible- The Bluesound Node manual shows RCA, COAX, and Optical outs, while the iFi Zen DAC manual only has USB input.

Maybe similar to different species, it’s impossible for reproduction ;)

Ditto on the "no HDMI" connector. Not sure what you mean by "external dc adapter" , . . maybe the power wall wart for the DAC? 

@soix is right, need to connect a USB cable 'tween the Node and DAC.

@kennyc  also right. Even if current set up breeds, the offspring will be sterile. 

My bad---it is USB, not HDMI. Sorry about that. I connected everything as directed and was able to toggle with the Node’s app and was able to activate the toggle to turn on the external DAC. However, once connected, there’s no difference in sound---everything is still going thru the Node. I tried headphones on the Ifi and nothing. The yellow light on the Ifi stays on for a bit then goes off. The true bass doesn’t work either so something is still not right. Do I need to do something with the RCA cables??