Is there a difference between the Desktop O2 vs Portable O2 in terms of audio quality?
It seems like they only sell the portable o2....
Sound quality should be about the same. The desktop O2 is just a portable O2 without battery, and have the power jack move to the back for a cleaner look. The O2 designer was planning to design a different desktop dedicated version of O2, but he disappeared awhile back. Afterward, some just make tweak to his original portable O2 design and make it a little more desktop friendly.
I ordered a 120 the other day. How would you rate the 120 compared to the odac?
ODAC sounds pretty much like UD100, but with support of 24/96. UD100 / ODAC has a classic ESS ES9023 sound for being very wide, open and have really good upper detail. The PCM5102 in UD110 in comparison has better texture over the mid and lower range. With UD120, it is really more like a good blend of the two, where you get better soundstage and upper detail than UD110, but also better texture over ES9023.