Could Class D really be that good?

@atmasphere  I was there initially but just like asr said "... The third harmonic hovers around -130 dB which again, is almost at the limit of what we can measure..."   It is inaudible either at that noise floor.

I am sure that, with such a low noise floor the Purifi / Hypex class D modules provides, the sound from it is transparent bar none.  I also concur with you that the resultant sound traits hinges on how the modules is implemented.  But I don't think the sound will be sweetened approaching to tube amp unless specifically with a filter or other component.  Maybe that is why VTV adds the input tube buffer.  Just my two cents.

@lanx0003 The differences you hear in the sound of amps, if FR isn't an issue (which most of the time it isn't) is the difference in distortion of whatever amps are being compared.

There are three things that define those differences. What frequency, if any, that distortion rises (IMO/IME this aspect of amplifier distortion is the most important), the distortion spectra and finally how much distortion. There's no filter that would make a solid state amp sound like tubes; just the distortion signature. So if a class D has the same distortion signature as a good tube amp, it will sound like a  good tube amp simply on that account. 

This is because our ears use harmonics to identify any sound. So you can see that if an amp is to sound musical, its distortion signature must be as innocuous as possible. To that end, the 2nd or 3rd must be significantly higher amplitude than succeeding orders, so as to mask them. That is literally what has kept tubes in business these last 60 years.

I agree that class D is well past the point of being "mature", by at least a few generations at this point. Class D amps can be amazing, or sometimes mediocre, just like tube designs or class A etc.

Nice to see quality become available at such a low price like this amp. I'll be looking into it for a small bedroom system.

@tubeguy80 DIY Audio Forum, will offer up extended info from builders on these Amp Designs, Bruno Putzey is  a point of reference.

I’ve really grown to like class d, and I’ve certainly noticed how different modules bring a differing palate of sound to your speakers. They can be neutral as heck, or, like the older ICEpower modules, have tons of slam. Having said that, has anyone tried to contact Red Dragon audio? I’ve sent the guy several emails, and no response. Are they going out of business? I was interested in one of their amps, because based on the reviews I’ve read, they seem to have the sound signature that I like from class d. 
Any info would be appreciated.