Yeah, Charles; whatever the cause was of the difference you heard, it's a near certainty that it wasn't the DACs. As Alan and others have pointed out, DACs have been a mature technology for quite a few years now and the small measurable differences that still exist have no audible significance. The concept of using the unit with the "better" DACs is badly outdated and Burr-Brown has been just a division of Texas Instruments for about a decade. They continue to make excellent DAC chips, of course, but no longer with any advantages over the several competitors in the industry. In some quarters a mystique still exists for the name "Burr-Brown", but it no longer has a factual basis.
