For what it's worth... I had to replace the tubes in my version 1 24/192 about 3 months after purchase. One channel was exhibiting "tube rush" noise. I was able to get replacement tubes from Triode Electronics (sorry, don't have web site, but should come up under search).
I replaced them myself, with absolutely NO degradation in sound quality. As I put it to my wife, replacing the tubes was likened to doing minor surgury on your house pet. Not impossible, but requires a steady hand, PATIENCE, and very good lighting/magnifying glass. Also BE SURE TO USE PURE SILVER SOLDER! - (for you do-it-your-selfer's).
BTW , I'm still completely enamoured with my player, now almost a year and a half later. It continues to please and impress.
As a side note, I found the supplied Black Diamond cones to sound fast, but lacked the depth and tautness in the bass. I replaced them with the eminently-affordable Vibra-Pods with excellent results. Imaging, speed, & resolution all still great, but with MUCH better bass reproduction.