the best of them being the bel canto ref600m hypex amps, I still found them lacking in realism and tonality..Yes they use the same Hypex NC500 modules that I have, I found the same they were the best of Class-D’s I’ve heard also, but also found the same as you about the sound, re body and flesh.
I then subbed out the smp power supply’s for a very large linear powersupply, and things improved greatly.
Then for even as much improvement again, I bypassed the input buffers totally and fed my dac into the NC500 module direct, this was a real eye/ear opener, like someone opened the window to the sound stage and depth department, transparent, very dynamic and great bass.
I can now happily listen to them in my second system, which is relatively easy to drive, they still don’t do it for me on the main hard to drive system.
Cheers George