There is nothing wrong with the internal dac in the Sony HAP-Z1ES. I own two of them, 1 for each system. I get jaw dropping sound from it in my main system and in my other system. It was rated A+ by Stereophile and it got some kind of award in TAS. I tried an Aurender N100H with a top line Wyred4sound dac2 DSD SE with Femto clock and all the other goodies and the Sony bested it hands down. The Aurender went back and I sold the Wyred dac. The software for the Sony is very good as well. I see no reason for myself to look for something better.