jred,
atmosphere nailed it XLR for the maximum win, at least with proper xlr cables
IMHO hi-end AIN'T hi-end unless it is differentially balanced. Alas most reviewers don't seem to understand that and test xlr kit with non xlr kit and even more bizarrely state in their review that they didn't hear any difference. I stopped writing to hi-end magazine editors about this stupidity over a decade ago. It falls on deaf ears: Go Figure
That aside, you don't really need a tube preamp to get 3D sound. I had it with PS Audio Stellar GC dac and have it with my Audio Alchemy DDP-1 + PS 5. My amp is AA DPA-1 (class D)
For cabling I highly recommend WireWorld. You can get really good deals on their 7 series now that they've introduced the 8 series
hth