Class D = Trash?

stevecham,

     You asked:
"I'm not reading consistent sonic and utility praise for the format. Why is that?"

     I can only speak for myself but I think many class D users will probably agree with my answer to your question.   I don't specifically praise the sonics, or mention any of the usual terms used to describe the sonic characteristics of amplifiers in the past, in any of my posts on this thread or whenever I've attempted to convey  the overall sound of my several class D amps  for a very simple reason that is very obvious to anyone listening to a good class D amp in their system:

     Good class D amps are extremely neutral, have no consistent sonic signature that is imparted onto the music and therefore there are no sonic qualities to criticize or praise.
     Criticizing or praising the sounds one hears through a good class D amp is essentially just an evaluation of the music since there is nothing  discernible that is added or subtracted from the original signal.  In my experience, good class D amps behave just as many have consistently described how an ideal amp should behave; like 'a straight wire with gain'.

    As to consistent utility praise for the format, I think you need to reread  this thread and pay closer attention because the practical advantages of class D amps when compared to traditional amps has been well covered in this thread. I'll summarize the utility advantages of class D amps have over traditional amps, however, to save you the time:

 Class D amps are much lighter, usually much smaller, are significantly more efficient, produce much less heat and generally are less expensive than traditional ss and tube amps.  I also believe class D amps will be proven to cost less to maintain and operate  while determined to be more reliable than traditional amps as data is accumulated and analyzed.


Tim  

 
        
 R

     

stevecham,

     You asked:
"I'm not reading consistent sonic and utility praise for the format. Why is that?"

     After rereading your post from 8-28-2017 at 1:00am, I now realize I may have misunderstood your exact question just prior to posting my reply on 9-19-2017 at 8:36am.  I originally understood your question to be referring to why all posters on this thread, "that posted favorable experiences listening to class D amps",  were not consistently reporting sonic and utility praise for the format.  I currently understand your question to be referring to why all posters on this thread, "that posted either favorable or unfavorable experiences listening to class D amps", are not consistently reporting sonic and utility praise for the format.
      In other words, I think your intended question was basically:
 " Why do some posters on this thread report positive experiences, while some report negative experiences, listening to class D amps?" Please let me know if I'm incorrect.

     IIn any case, this is a very interesting and insightful question that I believe gets to the very heart of the issue concerning why some really like the performance of class D amplification and others really do not.  This difference of opinion is currently reflected in 2 diametrically opposed current forum threads:
  
This one titled "Class D= Trash"  started by madavid0

versus

The opposing viewpoint titled "Class D is just Dandy!" started by erik_squires

 This dichotomy of opinion on class D performance has also confounded me since I first learned of class D about 5 years ago and began reading Audiogon and other audio forum opinions on their performance.

     I recall the opinions on class D from this time alternating between glowing reports and those that claimed the sound was "thin", "strident", "shrill in the high frequencies" and comments like "it just seems like something's missing".  The only consensus of opinion I remember from about 5 yrs ago was that the bass performance, noise levels, distortion levels and detail levels were considered by almost all to be very good along with the obvious utility advantages of small size , low weight, low heat and relatively low cost.  My perspective is that the conversation hasn't changed much over the past 5 years.

     I can sympathize with your confusion since I recall being equally perplexed at the time about why there were such a differing opinions on class D performance.  Also at this time about 5 yrs ago, my high powered class A/B Aragon 4004 MKII amp's power supply capacitors leaked and it went dead.  I had to make a decision on whether to have the amp repaired for a quoted $1,800 or buy a new amp.   This was a pain at the time but, in retrospect, I now consider this amp failure as very fortuitous.  
     I decided not to spend $1,800 to repair my nearly 15 year old amp and instead viewed it as an ideal time to audition a class D amp in my system and just determine for myself how well or poorly class D performed.  I considered this option as low risk (as it remains today) since many class D amp sellers offered generous in home trial periods with 'no questions asked'  full refunds if you were not completely satisfied.  I wanted an amp that at least matched the power of my now deceased class A/B Aragon amp (400 watts @ 4 ohms) that was stable into low impedance loads to drive my fairly inefficient ( 86 dbs/1 watt) Magnepan 2.7QR spkrs that I know sound best with lots of power.  

     So I chose an SDS-440CS stereo amp from ClassD Audio that had numerous good reviews, a 4 week in-home trial period, was powerful ( 440watts @ 4 ohms) and very affordable ($630 5 years ago and still $630 today).  This amp sounded very good right out of the box and I was thrilled with its performance.  It outperformed my former Aragon amp in every area I cared about; power, dynamic range, quietness, imaging, distortion, accuracy and musicality.  Oh yeah, it was also about 1/3rd the size and weight of my former amp, ran cool to the touch, consumed significantly less electricity and there were zero detectable EMI or RF interference issues in my system.  

     Needless to say, I kept this amp and it has now been operating faithfully in my system for over 3 years (currently driving my in-ceiling surround spkrs).  I've subsequently purchased additional class D amps (a stereo Emerald Physics amp to drive my Magnepan CC3 center ch and a pair of D-Sonic M-600 monoblocks that currently drive my Magnepan 2.7QRs).  All have performed equally well or better than my original ClassD Audio SDS-440CS amp and completely outperformed the very good class A/B amps they replaced. My combo HT and 2-CH music system is now completely class D amplified and I've been completely satisfied with the sound of my system for both for a few years now.  

     Now, this is just 1 person's honest opinion of the performance of good class D amps.
     I would urge you, and any other readers of this thread considering class D amps in their systems, to not take my or anyone else's word for how good the better ones perform.  Just audition one or more in your own system and discover for yourself how class D sounds to you.

     I say this not only because it's the best method to determine how any component affects your system, but also because it seems as if class D may not be the best solution for everyone.   I've been admittedly and repeatedly confounded by how class D has performed and been perceived to be so exceptionally good in my system while others claim to have issues with its perceived performance in their systems.

     Is it possible that some individuals have an 'allergic' reaction to class D produced sound or are more sensitive to certain affects introduced by class D amplification?  Can it be true, as georgehifi has adamantly and repeatedly claimed, that the Switching Frequencies currently used in most class D power amps (about 500 Khz) are too low and cause sonic anomalies in the audible range (about 20-20,000 Hz)? 
     I tend to doubt both theories because there is absolutely no scientific evidence I'm aware of to support either.  However, if actually true, it would go a long way in explaining the rather wide spectrum of reactions thus far concerning class D performance.  

I'm going to try and keep an open mind,
     Tim  

Also at this time about 5 yrs ago, my high powered class A/B Aragon 4004 MKII amp's power supply capacitors leaked and it went dead.  I had to make a decision on whether to have the amp repaired for a quoted $1,800 or buy a new amp.

  I decided not to spend $1,800 to repair my nearly 15 year old amp and instead viewed it as an ideal time to audition a class D amp  
 
It outperformed my former Aragon amp in every area I cared about; power, dynamic range, quietness, imaging, distortion, accuracy and musicality.
I'm going to try and keep an open mind,
     Tim  

Of course it did Tim, in case you don't know, your Aragon didn't die over night, leaky caps start to deteriorate the sound over many months even up to a year, so in actual fact you were comparing the sound of a very sick amp, to one that was healthy. The real comparison would have been to fix the Aragon amp then do the comparison.

Cheers George 

Hi George,

    You're probably right, my old Aragon likely died a slow death with its performance dropping so gradually I failed to notice it was ailing til it seized up. 
     However, I also noticed the exact same improvements when switching my decent quality and healthy class A/B center and surround channel amps for good quality class D amps.
     I've also  continued to leave my amps on 24/7 barring severe weather.  I've noticed a significant ($30-40) reduction in my monthly electric bill ever since.
     Good point, never the less.
        Tim