"I am planning on upgrading my tube amp when its current set of tubes start to go."
Don’t hold your breath, they will last a long time. I’m not a digital gear nitpicker, but have demoed one in my system for the CD deck. It did what it’s designed to do, and that is make the CD player a little less "CD sounding" I looked nice too, complimenting my PL HP.
The distributor is the one to address your long term concerns, not anyone here.
I went Denafrips Ares-R2R design. Le$$ and equally satisfying. My subjective opinion, of course.
Edit:
I misread your comments. I understood it as you already have a PL. Nevermind.