FWIW - I have updated ADC/DAC boards in my Altitude 32 (at very modest cost per channel), as per Trinnov this should bring another around 6dB of SINAD [or in the ballpark]
Not claiming any magic improvements with ESS vs old Burr Brown boards [that were tested by Amir] - but the fact is, that sound was off and it required renewed calibration to get back to overall SQ that I had before the DAC change.
While I agree with most of the statements here - I work in precision manufacturing od quite complex product - and we have a thing called "tolerance stacking" - while each part is absolutely OK on its own and within spec, they do not work together if not matched properly. Same can be valid also for Trinnov based setups, that are usually much more complex that your everyday Denon HT. We also need to acknowledge, that while Altitude measures competently, it is far from being SOTA DAC, with rising distortion in higher frequencies etc.
So I can absolutely imagine a situation, where changing a DAC board can have audible effects - if you combine it with e.g. some HYPEX Ncore amp with 27dB gain [that has elevated distortion in treble too], have some specificity on your speakers, there I can see how improving DAC board can help.