USB DAC Recommendation

I haven't seen your budget, but Grace M903 might inspire you. http://www.bhphotovideo.com/c/product/741484-REG/Grace_Design_M903_m903_Reference_Headphone_Amplifier.html

The Ayre QB9 is plug and play with extremely little setup. Ayre also provides detailed setup for Mac based systems on their website. The current unit is 24/192 and with your setup should adjust on the fly depending on the source content specs. Plus Ayre is pretty good about adding any upgrades for cost of parts/software in case HiRez bumps up to 384 standard (unlikely in near future). There happens to be a virtually brand new one for sale right now.

Full disclosure: The one I mention for sale is mine.

I currently own a Bel Canto DAC 3.0 w/BC USB Link, and an Ayre Acoustics QB-9. Both are IMHO incredibly good source components, with very different approaches. Connectivity is not a daunting issue with either.

But if I had your budget of $5K, I'd go as far up the Wavelength Audio foodchain as possible, until it's shown that something betters Gordon Rankin's asynchronous mode solutions, and then spend the rest on your high-res library.

The Empirical Audio Overdrive Signature should be considered. It has a fan so keep that in mind. The latest can do 24/192. It also has a volume control and can output rca , balanced, or both. This is a dac worth hearing!