Class D Technology

That's general idea, but simple it is not. None of current class D amp modulators uses triangle waves.  If anything it is more sinewave and closely resembles modulator use in Delta-Sigma converters, that produce similar output.  SACD is also a product of such Delta-Sigma modulator and it is basically class D output signal (PWM).  In addition to modulator alone there are different configuration of output stages, output filters, multiple feedbacks etc.  Let just say that it is so "simple" that it took whole PhD work of Karsten Nielsen (Icepower) at University of Denmark to describe theory behind it - much less actual implementation.  Once you take FPGA approach to class D you will find that it is very, very complex.

 

The real strengths of Class D are low cost, high efficiency (about 85%) and because of the latter, smaller size as large heatsinks are not as important.

Lower cost for manufactures, which seems to result in higher margins instead of reduced retail prices. Manufactures have to of course be careful of cannibalization.    

Yet you, Mr. Designer, dismiss Class D as nothing more than midfi.......

Apparently you've not read this thread or you would not have said that; IOW this statement is false.

Lower cost for manufactures, which seems to result in higher margins instead of reduced retail prices. Manufactures have to of course be careful of cannibalization.

This is true- and is a time-honored technique in the world of audio going back a good 60-70 years. First I can recall is when they went from electro-magnet speakers to permanent magnets. Permanent magnet speakers are cheaper to make but we didn't see the price go down way back then. After that it was the transition from high efficiency loudspeakers to lower efficiency types as transistors came in; lower efficiency speakers are cheaper to make but we didn't see the price go down all that much. Then there was the transition from tubes to solid state. Solid state amps are a lot cheaper to build- no filament circuit and no output transformer but the price really didn't go down.  Then we went from LP to CD and CDs are lot cheaper to build but we didn't see the price go down (instead we saw the price of LPs go up after the record industry sorted out that there was still a demand...). Now we're seeing class D supplant traditional solid state in many ways but for some reason they aren't particularly cheaper even though they are cheaper to make.  

I have no dog in this discussion/fight/whatever, but FWIW I believe the statement Mr_m is referring to is the following:

Atmasphere 11-3-2016
Right now the technology is to the point where the amps have become practical for mid fi, but they still have a ways to go before they can challenge a good class A transistor amp or a good tube amp. There is no question that this is a technology to be watched.

FWIW I do not interpret that statement as "dismiss[ing] Class D
as nothing more than midfi......."  As I read the statement it does not by any means exclude the possibility that the best present day implementations of class D may be much better than mid-fi, while nevertheless not being as good as what well implemented class A solid state or a good tube amp can presently offer.

Personally I take no position on this, having no experience with class D.  But that is how I interpret Ralph's statement.

Regards,
-- Al