I don't want to beat a dead horse but I'm bugged.

Many amplifiers on tested on Stereophile and ASR meet those criteria

This statement is misleading IMO. Most fail requirement 1) of my prior post. If you look at the distortion amount and its spectra, you’ll find that most amps have distortion rising with frequency and the spectra changing along with it.

This is because (as I’ve mentioned before) that they lack sufficient feedback, because they also lack sufficient Gain Bandwidth Product. There are exactly two ways around the problem of rising distortion and changing spectra:

1) build the circuit with zero feedback and wide bandwidth

or

2) build the circuit with really enough Gain Bandwidth Product to support over 30dB of feedback (such that feedback is actually the same at 15KHz as it is at 100Hz).

Most amps spec’ed to have ’30dB of feedback’ might have that at 1KHz but they will be less than that at 10KHz since the feedback is falling off due to insufficient GBP. This causes distortion to rise with frequency and it also means that the distortion caused by the application of feedback can’t be corrected by the circuit. That translates to ’harsh and bright’ and we’ve all heard amps with this problem; we’ve been hearing them for the last 60-70 years! There are plenty of amps made like that today and only a very few that actually meet the requirements stated in 2) of this post above if they have feedback.

I do believe at some future point this dilemma will be properly solved. It sure is not the case now.

Its not that we as an industry can’t do it, its that we lack the will, plain and simple. You do also need to know enough to understand how something will sound by looking at the distortion spectra... I’ve no doubt that some of these measurements don’t occur because there isn’t the education out there to really understand the data! Plus- heaven forbid- you know how something sounds by looking at the measurements!

This article is about this discovery i spoke about above about Oppenheim and Magnasco and our model of hearing and dac design ...

i think that this clarify andjustify atmasphere opinion but from another perspective which is not amplifier design, but more hearing abilities in itself, but i am not a specialist... 😊

Perhaps some day they'll innovate a robot that replicates my sensory perceptions and attaches a measurement regime conforming to those preferences. The robot can make the rounds. listening and measuring  every component existent in the world and report back. I could then objectively put together components best conforming to that measurement regime and build the best possible system for my listening preferences.

@atmasphere

I’ve no doubt that some of these measurements don’t occur because there isn’t the education out there to really understand the data! Plus- heaven forbid- you know how something sounds by looking at the measurements!

If we reach a point where sound quality can be accurately predicted by measurement I’d have zero resistance or issue with it. My point is acknowledging we are not remotely close to doing that now.

Currently used measuring techniques seemingly can’t hold a candle compared to the extraordinary capabilities of the human ear-brain axis processing pathways (Thank you @mahgister ).

You can use cheap off the shelf Op-amps to allow any mass produced entry level DAC to measure quite well and yet sound utterly underwhelming (Like crap).

Charles

@sns @charles1dad 

Would the issue be that you don't want accuracy?  You want artifacts?  I think that is the conclusion that can be drawn.  I don't think Mahgister is remotely accurate in this regard, not regarding electrical signals. Those we can measure with extreme confidence fortunately, or my job would be impossible.  If you do not want accurate, I doubt there is 100% correlation from human to human, so the only way to know what artifacts you like is for you to listen.

I can run pure 2-channel, or through the AV processor. Depending on my mood, I will listen using the AV processor and ambience surround settings. It is not accurate, but often is a more pleasant listening experience. It is more alive, with all those buzz words that audiophiles like; wide sound-stage, presence and sounds more like a live performance. It is obviously artificial though.