As a former NAD M2 owner I would be interested in such a product ONLY IF there were an asynchronous USB input. Many others have done the PCM--->PWM---->analog amplification.(eg. NAD, Lyngdorf) But to my knowledge, no manufacturer has done it with a SOTA input stage. S/Pdif input on any DAC is by definition synchronous and therefore prone to much greater input-related jitter than the best asynchronous USB module/driver available from the industry leaders eg. Weiss, Wavelength, Empirical Audio, Playback Designs, Ayre etc.
I think what Jonathan is saying is correct. Once you go this route, you are stuck with an outdated design that can only be fixed by replacing the entire unit; which is what I have done with my NAD M2.
I think what Jonathan is saying is correct. Once you go this route, you are stuck with an outdated design that can only be fixed by replacing the entire unit; which is what I have done with my NAD M2.