Competitive class D amp suggestions

Speaking of 2nd and 3rd order harmonics and their influence on what we hear...this is an interesting post/analysis.....

@snapsc Thankyou for that link, that is tremendous information.

This leads me to wonder about the virtues of Purifi module Class D amps. Tests reveal the near total absence of any audible 2nd and 3rd harmonics.

I guess it depends on the maker using Purifi technology, but I have recently been reading all I can about March Audio.

So "good" is bad. True.. While I haven’t auditioned, I remain cautious.

I am very sad that Ralph’s Class D is designed only for Nth America and Canada (and perhaps a few others) electricity supply, otherwise I’d be placing my order.

AGD? Hmm. If I really have to, kinda thing.

I'm not an engineer but I suspect that the Purifi is similar to the Benchmark....drive the distortion as low as possible...period, the end...and obviously a ton of people really prefer that sound.

Since very few designers talk at length about what their 2nd or 3rd harmonics strategy is...you don't know for sure what you are getting unless the amp has been tested or the designer will tell you.

I have a buddy who posts here pretty often...he has a Purifi amp and a few other amps as well.  He says that the Purifi actually sounds fantastic...strong low end, really nice top end...good sound stage...BUT...he says that compared to his other amps, it is emotionally uninspiring which to him means that while it technically sounds good, it doesn't seem nearly as musical as his other amps that are know for actually having some 2nd and 3rd degree harmonics.

Is this real?  Is this imagined?  I don't know but since there is more and more being written now about something that Nelson Pass identified 20 years ago...maybe we will all learn more in the years to come?

Very curious to hear the difference between my AGDs and the Atmas.

In chrome, my Audions are $8400. The Atmas are only &5400.

@clio09 

Your Berning OTL is something like $80k… is it not? And the Atmas go head to head??!

Thanks for sharing to this link!

I had a brief look at this information, and may have a more detailed look afterwards. I understand now more about harmonics and the distortion. I  general, much depends on which particular mathematical model is used . Here using merely a third degree polynomial might not be a most refined  way to model this   problem.  But it's always difficult to find a precise mathematical model. Like in quantum physics, the quantum equations somehow work. The outcome though is difficult to explain from our Newtonian point of perception of the world. Something similar maybe happening in distortions and measuring the distortions. In fact the formula that I just saw for measuring total harmonic distortion is a bit rough to me. So based on that formula the measurement might not say too much or even could be not really relevant. But there is an immediate practical observation that the second order  harmonics somehow amplify middle and high frequencies making them sound softer, and the third order harmonics in fact amplify the amplitude so the sound becomes more dynamical. Based on these practical observations mekes me to think  that both kind of distortions are good.  Auditioning now my set tube amplifier and analyzing what I have just read I understand and feel more what is happening. 

From here on THD will be irrelevant for me to judge about audio gear. Purifi model will neither attract me any more. As I suspect, it is hard to achieve 100% of linearity, i e., an ideal natural sound preproduction. In this regard, the second and third order harmonics could be helpful. I guess this is merely the reason why many people including myself like tube amplifiers. 

Actually, I don't know how the second and third order harmonics are dealt with in class d amplifiers in general, and in GaN class d  amplifiers, in particular. Any input on the subject would also be appreciated. Thanks again for your input.