@daledeee1 SBooster makes an adapter for Lumin that allows you to hook up a LPS. I upgraded the power supply on my Node 2i and it made lots of improvement. I used a PD Creative board. They also make Power Supply improvement for U1 mini.. Might affect warranty. Just food for thought.
Yeah, I'll certainly be doing the SBooster thing before long. As for the rest, I'm quite satisfied with the Lumin at this point. Obviously the Aurender stuff has a lot of very passionate advocates, but upgrading the SFD-2 just doesn't make sense as long as it works. To be clear, it's the MKIII version which is vastly different from the others. It also went back to Parts Connexion a few years ago for further and fancier upgrades. Detail is mind boggling and it's not at all a weak link. In fact, at this point I'm hard pressed to find any weak link in the system that wouldn't cost a fortune for only miniscule improvements, if any. In any case, thanks to all. The Lumin has greatly improved my life.
Next project: retweaking speakers. After fixing/recapping the preamp the bass was "fixed" too. I'd forgotten what it originally sounded like. That's all a topic for another thread.