5% THD to .000 THD SOUND

Some forms of distortion are often associated with a distinctive sound that may have unique appeal and sound. Performance and sonic appeal are not the same thing.

Think of digital photography. There are many ways to make a photo that is accurate in terms of its representation look better or worse. In either case it’s a form of distortion in that the original is less accurately presented.

What one likes or not is almost always a subjective determination. Accuracy alone may not be the full ticket. But accuracy is objective and a good place to start always I think. In my case I think I strive to end up there as well. I want to hear the variations in recordings not have my gear give them a particular flavoring.  Especially since I listen to all genres of music. Old and new.   So much variety in each piece of art to hear.  No special sauce needed. 

Great analogy, Mapman.

Revealing the nuances and different character of individual recordings is exactly what the Kondo Kagura excelled at doing so impressively.  No "special sauce" required.  This along with its clarity, openess and naturalness is what made it stand out relative to the Pass-Marten pairing.  This combo did a very good job of sorting out recording differences also The Kondo room/system  just did it better based on my listening encounter. 
Charles, 

Something to keep in mind is that "harmonic distortion" is a way of measuring a distortion from an amplifier, you don’t play music, for instance "at 5% distortion". The amplifier is driven by a single frequency at a time to some rms voltage (or power) output level (typically), under load of some kind, and the level of harmonics relative to the drive level are measured. Music isn’t at any constant rms voltage level, and not at one frequency at a time, so the conditions of the test seldom occur at all, or if they do, they do only for a very brief instant. Usually the harmonic distortion is given at the upper end of the amplifier’s output power capability, as that is where it is nearly always highest, and is given to indicate where the amp might be expected to be running out of juice.

With music, you might hit that peak output power for maybe a millisecond or so, and unless there is a lot of it hitting or exceeding that peak, you won’t be experiencing the effect that mght occur up there. The average power with hifi music is way lower than the peak, so if anything, the relevant distortion at the lower power would be what might be relevant.

The percent distortion spec, as usually given, should be read for the POWER level that produces it (i.e., to indicate what the manufacturer assumes is the maximum power the amp might do). NOT for the distortion level that the manufacturer is calling its limit. An amp with a soft clip can go near that maximum without distressing you because it takes longer to get there, and won’t suddenly go way higher in that region. An amp with lots of feedback (and a low distortion spec to match, used to indicate the power) will usually go from low distortion to high distortion with only a small increase in the power produced. The spec may be 0.0000x% where they call it, but it will probably be 5% or worse with the power level just a smidge higher when the amp clips.

Not making a comment on which is the better amp, just about the "distortion spec". Unless it is given at levels way lower than the amp can do, read it is as a POWER spec.

Hello bwaslo,
Your explanation makes a very compelling and logical case for the seemingly overstated importance /relevance of the THD specification. It certainly is consistent with the not infrequent observation of relatively poor measuring components that sound exceptionally well. Stereophile reviews are a good example. A reviewer says a component sounds terrific, yet subsequent test bench results are average or even poor. Conversely there are examples of excellent measuring components that sound bad. Again, this is why Einstein’s quote regarding what can and can’t be measured is timeless in its profundity.

It is fair to say however that some specifications and measurements are more relevant than others. On the other hand THD may be less meaningful and predictive than is generally belived. Good post bwaslo! An isolated measurement under test conditions may have little correlation with actual music signal performance quality .
Charles,