BTW, I'm kinda late to the party but I finally found some time to play around with my friend's STU:
Much has been written about it and it would rather avoid repeating the same things all over again but to my ears the best option is to set it for fixed volume line-out(this will bypass its volume pot) and then use this opamps combination fed to a discrete headamp:
two OPA2107AP for I/V and two OPA132U soldered onto an adapter as buffer(single opamps are a wiser choice for stereo signals, providing far superior channel seperation due to the fact that nothing is shared as clearly explained in the OPA1612 datasheet).
I'm listening to it as I'm typing this and SQ is really really great, Asus took the market by storm a few years back with the STX and they're back at it with the STU IMHO
It did take me quite a lot of rolling in order to find a combination I'd really like but it now provides a very deep and wide SS, a not too detailed or too distant sound.......just a great sounding easy-going DAC that doesn't try hard to impress you with an overly percussive or agressive sound, great deep bass, immersive SS, very musical mids, <1ppm CS2000 reclocker, ASIO drivers & UAC2 compliant = what's not to like really
Edited by leeperry - 10/15/13 at 6:01am