The DAC usually sounds best after it has been on for some hours. Clearly, I turned the DAC off, let it cool down, etc before turning it back on.
The new tube is NOS with no hours on it. Usually tubes sound better after some time settling.
You can hear a change pretty much right off after letting it warm back up a bit. It is not as profound as changing DACs mind you, but it seemed to push a little more space between the images (in a good way). I'm curious to see how it goes from here. I kept the same tubes in the amp and I'll keep them both steady for the next few days to see if there are any more changes.
-Chris
N.B. A 1st DAC roll makes me envious of @leftside and @Monsterzero with their TRPs (tube roller's paradise)!