Prices have gone up, but if one is in the US or CA, can't beat the buckeyeamp that ski2xblack link. I have been using one for a couple of years now, it is transparent and quiet even just using RCA to XLR cables. My only cautionary note on those NC502MP (better value than the NC252 imo) is, if you push it hard you might want to use an external fan (depend on the contents and one's listening habit), but that's $25 solution for a near silent one. If in Europe, there are a couple of better choices.