I recently bought one of these little wonder dacs for 122.00 along with an upgraded 18.00 radio shack power supply. I must say all the hype is true. Great sounding dac when used just as a d/a, better then cambridge 500se and lex dc-2 dacs!..Very smooth, unveiled almost sacd like. There is a tube 12ax7 in the a/d side with a knob that controls tube warmth up front. In order to use the tube to warm up something use must use the a/d side. I did an experiment last night. I hooked up my cambridge 500se digital out to the art digital in and then art digital out to the lex digital in, this way I know it going through arts d/a a/d and then lex d/a but what the heck.It was wonderfull, it really give my lex that tubey sound I was looking for! plus your able to dial warmth up with a knob on front. Secondly I hooked up the art analog out (no tube warmth just d/a) to my anthem 2prel tube pre.Now my lex is hooked into the anthems ht bypass, so at the push of the anthems bypass button was able to switch back/forth between using the anthem with straight art d/a and the lex with the arts d/a a/d (tube warmth set full blast)...Both sounded great, the anthem/art had tighter bass and was a bit clearer but the lex/art with warmer/smoother more analog sounding. This ART DI/O is a great little dac and can be used a thousand different ways!