The sound quality from DACs - is it all the same?

@rlawry 

Which $360 DAC is?  Thx.

So it seems this thread is coming to the conclusion that better sounding DACs don't meet any objective engineering requirements better than cheaper dacs. It's not that they produce the signal more precisely, but that they add some special sauce that creates a more pleasant stereo listening experience for some listeners who find the experience worth the extra cost. 

@lanx0003  The $360 DAC was the SMSL SU-8 v.2 Anniversary Edition.

@asctim

I would refine what you said a little. Designers start with solid design that produce great sound with in high level requirements (watts per channel, gain… etc.). Then they will swap sub components like capacitors, resisters, special placement… etc to make it sound great… often the end product will sound much better… but not test as well. It doesn’t take anywhere the engineering time to create a component that just tests well as one that sounds great. Hence higher cost. Also why choosing equipment by specs will seldom sound good. So, the “secret sauce” is upgrading sub components and listening over and over and over during the design process and using much higher quality components.

@ghdprentice

Sounds great according to them. You would wonder how they assess what sounds great. If it’s done by swapping components and then blind testing that would be most interesting. Then of course I’d re-test to see exactly what changed because it may be possible to achieve the same result in a more cost effective fashion. This would also add to a body of knowledge about which deviations from linearity sound great and which don’t. If the change passes a blind test but nothing measurably different can be found then that is also an extremely interesting finding that would expand science and engineering in ways that would extend past the field of hifi. I see little of that kind of contribution from the world of audio reproduction happening, so I’m convinced that the "secret sauce" has to be some audible deviation from linearity that offers nothing new to the general fields of science and engineering, and it seems unlikely that expensive sub components would be required to create the most pleasing effect unless one grooms one’s tastes in that direction. This gets me thinking of moissanite vs diamond. Moissanite actually exceeds diamond for fire. It diffracts light more strongly. This would seem desirable but since it is known that moissanite is cheaper than diamond the extra fire is seen by some as a tale tell of it’s cheapness, thus it is not as beautiful as the more restrained fire of diamond.