Best USB DAC for 1000-1500?


I'm looking for input on which USB DACs to look at for 1000-1500 used. This would be a present for a relative who is currently using a budget Scott Nixon Chibi 2 in his rig. I was thinking a Wavelength Brick but any other DACs to consider? Thanks
latinsamba1
Interesting commentary on the Brick V3. My relative has a simple system consisting of Almarro 205a and Omega Super 5 XRS paired with the Scott Nixon DAC. He had a tight budget so he skimped a bit on the source but his system sounds really good for the money. Due to WAF issues he won't be able to upgrade to larger speakers and he doesn't own any vinyl so I figure the logical upgrade is a better DAC.
I haven't heard the Wavelength Brick but I own the Wavelength Proton and love it, I'm sure the Brick is even nicer.

I've also gotten to audition the Ayre QB-9 which also uses the Wavelength Asynchrous technology and was blown away. You may be able to pick up the Ayre used on the high end of your budget, but I'm not sure what they normally go for.
Another HUGE thumbs-up for the Tranquility DACs. I was so impressed with the original Tranquility that I upgraded to the SE. I recently bought the Ayre QB-9, just to compare it to the Tranquility SE. The QB-9 is a very impressive DAC, very detailed and accurate, but both my wife and I found that the Tranquility was more "musical". I really wanted to prefer the Ayre, due to its ability to handle hi-rez files, but the Mac Mini / Tranquility combo is just stellar.
I ended up buying a used Tranquility (non SE) after reading the lengthy thread on Audiocircle about it. Before I gift it to my relative I want to compare it in my system to my RAM modified XA9000es. That could be a big mistake on my part :) At any rate, I hope that this will be a huge step up sonically from his current Chibi 2 DAC.
Latinsamba1, if you really want to get the best sound out of the Tranquility, try using the latest Mac Mini for server with Pure Music or Fidelia. I have the latter, and it is noticeably better than iTunes.