Does this mean that the DAC will be powered from the PSU instead of USB, since an optical connection obviously can't carry power?
I love my WA7, but I've never liked that I'm forced to run the DAC off of USB power. It comes in handy when I sometimes want to quickly plug into a system where I don't need the amp portion, but for my permanent desk setup, I'd like to not use dirty USB power. I'll probably buy an isolator someday, but for now, I can't afford to spend money on it; I need a new power amp for a set of speakers I just bought.
Ideally, it would be nice to be able to power everything off of the dedicated PSU, but have separate switches for the DAC and amp sections, as there is no reason to let the tube heaters burn your tube life away if you're only using the DAC.