I have a bluesound node 2 in my system that I use to feed my standalone Maverick Audio TubeMagic D2 DAC. I had honestly never even connected the analog outputs on the bluesound node 2 before today, but your post prompted me to do so.
I've read that the bluesound node 2 has a very "tube" sounding DAC. My initial response when I first switched from the standalone DAC to the bluesound node 2 was that it had a much softer tone. I left some music playing in the background and it's clear that the bluesound node 2 doesn't sound bad in my system.
I decided to take a more direct approach and did an A/B using one of my current favorite songs (Go Tell it on the Mounting by For King and Country) and the Maverick Audio TubeMagic D2 DAC was clearly superior to my ears as there was more air around the different parts of the music, I could hear "into" the music, and the bass was tighter with a more viceral presentation.
I have upgraded the Maverick Audio TubeMagic D2 DAC, so here's what it would take to duplicate it:
Maverick Audio TubeMagic D2 DAC with upgraded OPA627 opamps and GE5670W tube - $289 regular (on sale currently for $229)
Sparkos Labs SS3602 Dual Discrete opamps - $80 (x3)
I have upgraded the tube to a Western Electric 396A that I paid about $90, but I don't think that I can hear a definitive difference from the GE tube that it replaced. I was able to pick up the Sparkos Labs opamps for about $65 each on eBay by making an offer. If you wanted to pick your own tube, you can get the DAC without any upgrades for about $30 less.
You should be able to duplicate my DAC for $500 to $600 to your door and I think that you'd find it to be an upgrade to the bluesound node 2.
One cool thing with the Maverick Audio TubeMagic D2 DAC is that it has parallel solid state and tube buffer outputs and my understanding is that the three opamps are all in the signal path of both outputs. I found the Sparkos Lab op amps to be a significant upgrade.
I think that my DAC performs above its pricepoint, but I can't say how it would fit into your system. I have a Pathos Classic One MkIII amplifier with Focal 836V speakers for reference.