Class D is just Dandy!

Perhaps the ideas of Bruno Putzey hold some weight, as without his inventions and Hypex Ncore product, Class D amps might not yet have been in hifi amps. Here are his thoughts on Class D vs A and AB in an interview with Sound & Vision last year. 

S&V: Generally speaking, what are the key benefits of Class D versus the traditional Class AB and Class A designs that have long been favored by audiophiles?

BP: Efficiency and therefore the ability to construct amps that are powerful for their size. Only that. Modern Class D amps, in particular mine—ahem—sound good not because they’re Class D, but in spite of it. I can’t repeat that often enough. Left to its own devices, a switching power stage tries to do just about anything except amplify audio. You choose Class D to save energy but it’s all elbow grease after that. People don’t realize how much more challenging Class D is compared to Class AB. It’s truly an order of magnitude.


Read more at https://www.soundandvision.com/content/bruno-putzeys-head-class-d#Rp4w1mKbWublPse8.99

 "If bias was a disqualifier, these forums would be dead quiet."

Hi mapman,

     Good point. I agree that most of us, including myself, have developed biases along our audio journeys.
      I view my bias in favor of class D as based on research and personal experience using these amps. But I also realize that, in the end, all of our personal and particular biases are just our opinions.
   Rereading the previous 6-8 threads, I think the thread topic took a turn for the worse toward a discussion of bias and prejudice when I posted stating I liked the way erik_squires had characterized those claiming the switching frequencies used in most class D amps as being too low. This is erik's comment:

" It is the notion that Class D switching speeds are the cause, and that someday they'll be fixed that irritates me. It's a type of prejudice not born in evidence. It's the equivalent of "all feedback is bad" sales pitch for some amplifier designs."

I then posted my response below:

""Hi Erik,
     'A type of prejudice not born in evidence' is a very accurate and succinct way of describing how some class D detractors have a knee-jerk response, whenever class D is mentioned, of proclaiming a completely unproven theory that current class D switching frequencies are too low and negatively affect frequencies in the audible range."

     I thought that would be the end of discussions about bias and prejudice. However, cleeds than posted the following post responding to my post:

" It's interesting how some defenders of Class D amps go to such lengths to classify the critics of these amplifiers as a minority, yet then go on to claim that the critics are prejudiced. Hmmm ... "

     I found the point of cleeds statement above to be undecipherable and responded with a post asking him to clarify. In retrospect, I think I made a mistake posting my response since you responded to my post before cleeds responded to clarify.
   , I think your response of: " If bias was a disqualifier, these forums would be dead quiet. " was completely appropriate and accurate since my response standing alone, without a response from cleeds clarifying his point, just seems like me ranting about class D detractors' biases.
     I regret having to write this difficult post but I think it was important to clarify the sequence of responses to explain to readers of this thread that it was not my intent to turn the discussion toward the subject of biases and prejudice. My original intent was to complement erik_squires on his post, that succinctly and accurately described the efforts of a few class D detractors to claim switching frequencies are too low, when he stated " It is the notion that Class D switching speeds are the cause, and that someday they’ll be fixed that irritates me. It’s a type of prejudice not born in evidence." Subsequently, it was my intent to have cleeds clarify the point of his post, which I hope he will still do soon.

     I hope this post clarifies things for all.
     In conclusion, I just want to state that, although I currently use class D amps and have admittedly developed a favorable bias toward or opinion of them, I don't think they're right for everyone and I know that others have developed a favorable bias toward or opinion of other amplifier types. I think that's just the way it should be.

Sorry about the confusion,
     Tim  

Noble, thanks for that well thought out clarification.

My ears tell me the latest and greatest Class D sounds great, absolute top notch sounding when done right, top to bottom, can compete and often win with most anything else, at least in its price range.

My technical self tells me that the technology is still not yet fully mature, has not yet peaked, and that it will continue to only get better, at least on paper and in tests. To what extent that matters practically listening to music  right now is another question. Just like the old is CD resolution good enough question.

Practically, it has not mattered enough to stop me from being squarely in the Class D camp for several years now, starting with when I acquired the Bel Canto ref1000m amps in my main system several years back and more recently when I gave the BEl Canto c5i a crack in my second system, thereby avoiding taking an experimental plunge into tube amps and the speakers needed to make those sound best.

"I don't know why people have to defend or overly praise Class D compared to other amplifier topologies when the end result is if you like it then keep listening." - @sfseay
Those defenses, explainations, and informed opinions are what helped motivate me to explore and eventually buy a class D. We don't all come to the forums from the same level of expertise or knowledge.

"I don't know why people have to defend or overly praise Class D compared to other amplifier topologies when the end result is if you like it then keep listening. - @sfseay
Those defenses, explainations, and informed opinions are what helped motivate me to explore and eventually buy a class D. We don't all come to the forums from the same level of expertise or knowledge. @2channel8 - Class D vary wildly in quality.  To paint with a broad brush and heap praise on Class D amps is silly.  There are plenty of bad Class D amps, but you seem to put all of them in the same category."

I have broad experience with several different Class D amps, and I listed the specific Class D amps I have owned and used.  Having said that, I wouldn't lump them all together as quality amplifiers.

What Class D amp are you currently using?