Congrats on the Node 2i! While I don’t have one, I’ve bought PowerNodes for (granted not very audiophile) family and friends based on the reviews alone and they are really happy with them.
Another vote for RME ADI-2 if you can swing it. Really excellent, neutral but not dry. Much better than Ayre Codex in my experience. With the Ayre I was always itching to go back to my PS Audio DirectStream; not nearly so much with the ADI-2. There’s also a few good comparisons online to the Chord Qutest, where the ADI held up pretty favorably. I don’t know that it will be THAT big of an upgrade over the Node internal DAC though. I thought the Node 2i was pretty good as is?
What I like about the ADI is, as you’d expect from pro gear, they have achieved bulletproof performance through a high degree of technical sophistication. Eg it performs and sounds as it should with a very ordinary power supply. Sure, its performance is capped by the internal switching supply and op amps, so it will never sound like a MSB Reference or what not, and some DACs at 3-5x the price will better it in aspects. But it gets 80-90% of the way there with zero effort. I’ve noticed that while I prefer my DirectStream, it’s not as consistent - eg the “sounds better late at night” phenomenon is way more pronounced with the PS Audio, which is also sensitive to power cords. The RME I can just throw on with an rPi over USB and Mogami interconnects and it will sound reliably great.
There are a couple things things to watch out for with the ADI. It is pretty much dead neutral, so if you are looking to add some flavor to your system or make digital resemble vinyl, look elsewhere. And if you really need to use it with balanced XLR - the performance seems somewhat compromised via RCA. Sounds like that won’t be an issue here.
With respect to all the other opinions here, I would not worry too much about R2R vs. bitstream. My experiences do not align exactly with the character some are ascribing, especially “musicality” which is highly subjective. I don’t find one architecture to be inherently more musical; the most I can say is that ladder tends to have sharper leading edges, which makes sense since it has theoretically infinite slew rate, while the gentler analog filters of bitstream might make it a bit smoother and more coherent top to bottom. In any case, the overall implementation of the entire DAC matters much more. Case in point: my previous reference DAC was based on PCM1704 ladder, passive IV and tube output stage. My current - bitstream FPGA - could not be more different in technical approach.
As always, just $.02!
Cheers,
TAWW