I am not sure about the digital to analouge converters. The processor is a proprietary Yahmaha 32 bit. Have you tried emailing their technical support people.
A side note: The make of the DAC will have very little to do with the sound of the unit as long as it was well made. Yahmaha tend to use fairly good components in their receivers. I do not thing you have much to worry about. While the DAC are important to audio production from digital sources they are not the sole dictator of how a unit will sound. Most if not all people would not be able to hear the difference from one brand of DAC to the other in a blind listening test. Enjoy your unit.
