The job of a DAC chip is to convert digital samples into an analog signal. I believe that most modern, widely used DAC chips are already extremely accurate, so audible differences often come more from the surrounding circuitry than from the chip itself.
In other words, assuming the audio system is properly matched, it is usually everything before and after the DAC chip INCLUDING the power supply, clocking, filtering, and output stage, etc. that makes a DAC based component sound great.

