What’s the big deal with class ‘D’ anyhow ?

[La Dolce Vita]

No need for name calling here. I did no such thing and expect the same courtesy. I respectfully disagree. Class of amplifier has everything to do with the sound of an amplifier. Just as feedback has significant impact on sound quality. I never suggested that all class D amplifiers sound the same. I only said I never heard a class D amplifier sound good. That does not mean that I never will. In my opinion, this technology is being pushed for no good audiophile reason. If you like it, great. I don’t. I have seen many amplifier classes come and go. I have also owned a few (class H). But most did not stand the test of time. I have also seen great technology like ST glass go away. I cannot control the audio marketplace. I can only support the technology I think sounds the best.

No doubt everyone can benefit from keeping an open mind. I do not know how many Class D amps you have heard to feel confident in making such a generalization. It seems you may not have heard some Class D product like Mola Mola.

If not it’s a bit like saying you don’t care for gasoline powered cars, and for that reason only enjoy and buy diesel fueled ones. Perhaps those gasoline one’s you tried were not to your taste but for illustration if you only drove Yugo, Hyundai, Chevy, VW and a few others, you’d sound a bit silly drawing parallels to driving a Maserati, Cadillac, Volvo, etc...



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[a.wayne]

It is ignorant to suggest that all class D amplifiers sound the same. Just as it would be ignorant to suggest that all class A amplifiers are amazing sounding. Amplifier class of operation does not have much of anything to do with the sound. A talented designer can achieve the same sound regardless of amplifier class. Bruno Putzeys has designed class A amplifiers, and class D amplifiers, and as he says, amplifiers do not sound good (or bad) because they are class D.
One of the best systems I have ever heard, just happened to have a pair of class D amplifiers, driving Vivid Audio Giya speakers... I have heard most of the famous class A and A/B amps, PASS, Constellation, Big VTLs and ARCs, Soulution, Vitus etc, etc. There is nothing missing with the best of the latest generation of class D amplifiers (except noise and distortions). Different amps sound different from each other. But anyone who decides how amps sound by their class of operation, these days, is stuck in the past and telegraphing their responses.
I am happy not to have to deal with ancient, wasteful, distorted, overly large and heavy amplifiers of the past, and embrace the technology and work of really smart designers like Mr. Putzeys.
Although I am not a fan of blind listening tests in general, I would suggest that those who feel like the best class D amps of today do not measure up, do a blind comparison of the Mola Molas vs. the Solid State amplifier of their choice at the same price, as their is clearly a case of some kind of bias going on here.
This reminds of all the other audiophile myths I have been trying to overcome in my own thinking: feedback is bad, IC Opamps are always worse than discrete circuits, analog is better than digital, etc.

There is nothing wrong in liking class-D , if it works for you , its all good , as it is , I will purchase again when Class-D can pass a proper Squarewave and btw those are not myths ..

 

[La Dolce Vita]

There is nothing wrong in liking class-D , if it works for you , its all good , as it is , I will purchase again when Class-D can pass a proper Squarewave and btw those are not myths ..

For me whether it’s Class A, Class AB, Class D etc., it’s not about any one particular measurement or evaluation. It’s about the sound. If it sounds right to me and it gets my toe tapping that’s what matters most.


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[Speedskater]

No need for name calling here. I did no such thing and expect the same courtesy. I respectfully disagree. Class of amplifier has everything to do with the sound of an amplifier. Just as feedback has significant impact on sound quality..................................................

I will agree with 'barrows' on this. It's not about the Class of amplifier or the amount of feedback that makes an accurate, good amplifier. It's about the skill of the circuit designer. Now if you are looking for euphonic coloration's, then all bets are off.

 

[a.wayne]

For me whether it’s Class A, Class AB, Class D etc., it’s not about any one particular measurement or evaluation. It’s about the sound. If it sounds right to me and it gets my toe tapping that’s what matters most.


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Class Bias agnostic , so I'm with you , but i do need those square waves nice and square for the toes to tap ...





Regards


BTW, Speaker load and music type used for playback will determine what we use for amplification , not necessarily any specific topology, none are right or progressively wrong, it's all in the required application.

 

[Randy Myers]

Since getting back into this crazy hobby less than three years ago, after about a 15 +/- absents I have had to relearn everything. I am now 100% digital, my own custom built music server running Roon and HQ Player. I have heard really really really good turntable setup, a friend in our audio club has MBL, DCS, ARC Ref 10 Phone Stage, etc., etc..... and I like my digital setup better... (the minute he puts an album on I hear the pops and hisses, etc... and he has two of the best cleaners money can buy)...

Anyway; here is a list of amplifiers I have used in my system since jumping back in... In sound quality preference (to my ears in my system), with comments...

PS Audio M700 mono's (Class D) What can I say, to my ears, in my system the best I have heard, the reviews really do say it all. (still breaking in)

First Watt F6 (Class A) incredible sounding, just not enough power for long term use, way too hot.
PS Audio S300 (Class D) really nice sounding amp, just wanted the step up, new amplifier tech.
Goldmund Job 225 (Class A/B) (in my system twice) really fast, great impact and dynamic, just seemed a little cheaply built for long term use.
Quick Silver Silver 88 mono's w/KT-150 (Tubes Class A?) great sounding tube amps, just way too unstable and finicky for me (very hot).
Audio Research VT-50 w/Gold Lion KT-88 (Tubes Class A/B) really well made, nice sounding, but too low power and a little thin sounding for long term.
SST Son of Ampzilla II (Class A/B) nothing bad to say about this amp, did not feel comfortable to keep long term, and too early on in experimental stage.
Wyred 4 Sound ST-500 mkII (Class D) good, but something felt like it was missing to me.
McIntosh MC-7100 (Class A/B) just too old... something felt like it was missing.

 

[a.wayne]

Since getting back into this crazy hobby less than three years ago, after about a 15 +/- absents I have had to relearn everything. I am now 100% digital, my own custom built music server running Roon and HQ Player. I have heard really really really good turntable setup, a friend in our audio club has MBL, DCS, ARC Ref 10 Phone Stage, etc., etc..... and I like my digital setup better... (the minute he puts an album on I hear the pops and hisses, etc... and he has two of the best cleaners money can buy)...

Anyway; here is a list of amplifiers I have used in my system since jumping back in... In sound quality preference (to my ears in my system), with comments...

PS Audio M700 mono's (Class D) What can I say, to my ears, in my system the best I have heard, the reviews really do say it all. (still breaking in)

First Watt F6 (Class A) incredible sounding, just not enough power for long term use, way too hot.
PS Audio S300 (Class D) really nice sounding amp, just wanted the step up, new amplifier tech.
Goldmund Job 225 (Class A/B) (in my system twice) really fast, great impact and dynamic, just seemed a little cheaply built for long term use.
Quick Silver Silver 88 mono's w/KT-150 (Tubes Class A?) great sounding tube amps, just way too unstable and finicky for me (very hot).
Audio Research VT-50 w/Gold Lion KT-88 (Tubes Class A/B) really well made, nice sounding, but too low power and a little thin sounding for long term.
SST Son of Ampzilla II (Class A/B) nothing bad to say about this amp, did not feel comfortable to keep long term, and too early on in experimental stage.
Wyred 4 Sound ST-500 mkII (Class D) good, but something felt like it was missing to me.
McIntosh MC-7100 (Class A/B) just too old... something felt like it was missing.

This Amp : https://www.stereophile.com/content/ps-audio-stellar-m700-monoblock-power-amplifier

This Speaker: https://www.stereophile.com/content/kef-r700-loudspeaker-measurements


IMO, some who prefer the sound of class-D , really prefer the unclipped music signal from using higher power Class-D amps , as many were grossly under powering their systems prior to and the jump and drive offered by the additional power will lift the system to another level. In listening to Devialets, i did like the M400/400 combo best and so did the owner who had the smaller stereo unit before being talking into the 400/400 combo.

On his logans we did manage to dynamically clip the 400/400 on a few recordings and they would shut down from over temp, apart from that i thought them the best of the class-D genre, never heard the Mola Mola level stuff to compare...

Question: What kind of music genre do you play the most ...?

regards

 

[Randy Myers]

Now I listen to a lot of Jazz Vocals (Holly Cole, Norah Jones, Patricia Barber, Lyn Stanley, Jacintha, Diana Krall, etc.), some pop, classic rock, some hard rock even. Sometimes some folk music. I also enjoy what I refer to as progressive rock; Pink Floyd, Alan Parsons, Yes, Gentle Giant, King Crimson, etc. So a fairly wide range... very little country, a little classical, NO Hip Hop....

 

[AJR]

Based on my experience Class D has great synergy with electronic music.

 

[barrows]

Joseph: I was not calling anyone anything, please respect my words as I purposely did not say: "X is ignorant", I made a general statement.
I stand by my words. I have heard "bright" sounding class A amplifiers, and dull and foggy sounding class A/B amplifiers, and I have heard soft and recessed sounding class D amplifiers.
I have also heard fantastic sounding amplifiers from all classes (OK, probably not pure class B, but I still would not rule it out). So, class of amplifier design is not the defining factor of its sound.
As to the myths: I have heard, these days, components which incorporate IC opamps which give up nothing to components that use fully discrete parts selections-previously to this listening experience I believed the myth that discrete circuits are the only possible way to best sound. The same is true of the other myths I used to believe, they have been blasted to shreds by listening experiences of components which are in direct opposition to the myth. It boils down to the designer using the parts in a way which emphasizes their strengths and eliminates their weaknesses. Implementation, Implementation, Implementation.
The high end audio industry is suffering, and is real danger of disappearing, and the ever increasing price and complexity which some feel is necessary to achieve the best sound, and the elitism of some participants (including manufacturers and some dealers) is making our audiophile world look unattainable and undesirable to those who otherwise might be interested in better sound in their homes.
Somewhat ironically, now we also have a bit of a revolution happening in audio technology: due to both very smart and talented designers, such as Mr. Putzeys, who are not bound by the audiophile myths of the past, combined with huge breakthroughs in parts and computing power vs. size and cost. We have class D amplifiers which perform at SOTA levels for a fraction of the cost of previous designs, we have oversampling engines which work in software on a computer for fraction of the price of similar functionality built into a DAC, and things like volume controls can be done without losses in the digital domain for a fraction of the cost of doing analog volume controls (see LeedH). The only area where we do not have the same breakthroughs is in loudspeakers where the physical needs of producing fantastic sound still limit what better design and technology can do. Although if one is in a small space, things like the KEF LS-150 are breakthrough products in that area. Still we are being held back by the insistence on the old ways, ancient technology 100+ lb. amplifiers, with wasteful class A circuitry running at 25% efficiency, etc, etc...

 

[a.wayne]

Joseph: I was not calling anyone anything, please respect my words as I purposely did not say: "X is ignorant", I made a general statement.
I stand by my words. I have heard "bright" sounding class A amplifiers, and dull and foggy sounding class A/B amplifiers, and I have heard soft and recessed sounding class D amplifiers.
I have also heard fantastic sounding amplifiers from all classes (OK, probably not pure class B, but I still would not rule it out). So, class of amplifier design is not the defining factor of its sound.
As to the myths: I have heard, these days, components which incorporate IC opamps which give up nothing to components that use fully discrete parts selections-previously to this listening experience I believed the myth that discrete circuits are the only possible way to best sound. The same is true of the other myths I used to believe, they have been blasted to shreds by listening experiences of components which are in direct opposition to the myth. It boils down to the designer using the parts in a way which emphasizes their strengths and eliminates their weaknesses. Implementation, Implementation, Implementation.
The high end audio industry is suffering, and is real danger of disappearing, and the ever increasing price and complexity which some feel is necessary to achieve the best sound, and the elitism of some participants (including manufacturers and some dealers) is making our audiophile world look unattainable and undesirable to those who otherwise might be interested in better sound in their homes.
Somewhat ironically, now we also have a bit of a revolution happening in audio technology: due to both very smart and talented designers, such as Mr. Putzeys, who are not bound by the audiophile myths of the past, combined with huge breakthroughs in parts and computing power vs. size and cost. We have class D amplifiers which perform at SOTA levels for a fraction of the cost of previous designs, we have oversampling engines which work in software on a computer for fraction of the price of similar functionality built into a DAC, and things like volume controls can be done without losses in the digital domain for a fraction of the cost of doing analog volume controls (see LeedH). The only area where we do not have the same breakthroughs is in loudspeakers where the physical needs of producing fantastic sound still limit what better design and technology can do. Although if one is in a small space, things like the KEF LS-150 are breakthrough products in that area. Still we are being held back by the insistence on the old ways, ancient technology 100+ lb. amplifiers, with wasteful class A circuitry running at 25% efficiency, etc, etc...

IMO, The Hi-end been shrinking since the mid 90's and Class-D is not new technology, yes Bruno is a very smart engineer and has taken the topology to a higher level and the reason why old wasteful designs are still here, because to most audiophiles where music is life, it still sounds better and like real music ..

The physics is the same , only the marketing is different , enjoy ....


Regards..

 

[barrows]

"Class-D is not new technology"
Relative to class A, A/B solid state and tube it is. Any new technology takes time to mature and develop, and for engineers to learn how to get the best out of it. Class D is tricky and complex, and requires much more skill on the designers part, as they must be competent in both high speed circuit design and RF engineering to get these amplifiers to sound good, most ordinary, old school, analog engineers do not have the skills to design these amps. It is no coincidence that the best designers in class D are younger engineers. Early solid state amplifiers were not accepted by audiophiles either, until designers had enough experience developing them and figuring out how to make them perform well. Now most audiophiles accept that some of the best sounding amplifiers in the world are solid state, but this was not the case early in the history of SS amps.
Now we are at the point where class D has matured and is in the same conversation with all the best amplifiers in the world. But some still cling to the past and allow that to color their perspective.
BTW, I have vast experience hearing many of the best components in the world, and have been an audiophile since the late 70s, and have also worked in this industry for almost 20 years now, so I am not ignorant in the sound of say, PASS LABS, or Constellation, or Soulution, or Vitus, or VTL, or Audio Research Corporation, etc.
I would suggest that those who just lump all class D amplifiers into a category of "not good enough" need to get out and listen more. Like any amplifier, one "bad" experience is not enough to draw a conclusion from, as with any amplifier, matching to the speaker is critical. A poor combination can make any amplifier sound bad (or at least tonally out of balance).

 

[Randy Myers]

And this is one reason that when I jumped back into this crazy hobby I felt I had to relearn all I knew about audio equipment. Things had change considerably. The entire digital market did not exist (not counting CDs which had come out but were not really that good at the time).

So I have tried a lot.... A LOT of equipment. My budget does not allow me to buy everything I want, so I have worked ways of trying different gear, trades, buying used, upgrading a little at a time, to reach a point where I currently am.

Certainly not high end by today's standards, but a point of satisfaction. So I have gotten my pre-amp and amps to a happy point... I have a spinner that I rarely spin a disk in but that will never ever leave my system... I have been a KEF fan for ever, and was very happy to get a set that satisfys me needs, and now considering a DAC change even though I have had a lot of DACs in my system ....

I had to go through several amps to find where I was most happy... and I would say it has little to do with the class, but most the sound and the feeling it gives me. The advantage of Class D is pretty substantial if the amplifier gives the sound you like.... low power usage... and little to no heat (compared to Class A these two are night and day). Relatively low weight... much easier to work with.

 

[a.wayne]

"Class-D is not new technology"
Relative to class A, A/B solid state and tube it is. Any new technology takes time to mature and develop, and for engineers to learn how to get the best out of it. Class D is tricky and complex, and requires much more skill on the designers part, as they must be competent in both high speed circuit design and RF engineering to get these amplifiers to sound good, most ordinary, old school, analog engineers do not have the skills to design these amps. It is no coincidence that the best designers in class D are younger engineers.

Wait , what younger smarter engineers ...

Early solid state amplifiers were not accepted by audiophiles either, until designers had enough experience developing them and figuring out how to make them perform well. Now most audiophiles accept that some of the best sounding amplifiers in the world are solid state, but this was not the case early in the history of SS amps.

Class-D been around for at least 4 decades now it's not "new tech" , SS started competing with toobs in the late 70's on all levels, it's the SET which holds that sonic front on 100db plus speakers, to compete with SS.

Now we are at the point where class D has matured and is in the same conversation with all the best amplifiers in the world. But some still cling to the past and allow that to color their perspective.

As oppose to clinging to a possible marketing myth, maybe most feel class-D is not yet here , maybe thats it , clinging to what sounds good to them ..

I would suggest that those who just lump all class D amplifiers into a category of "not good enough" need to get out and listen more. Like any amplifier, one "bad" experience is not enough to draw a conclusion from, as with any amplifier, matching to the speaker is critical. A poor combination can make any amplifier sound bad (or at least tonally out of balance).

Agree lumping is chaotic at best , kinda like lumping those clinging to the past and correctly , speaker load determines what amp drive is best , the topology dictates that drive ..

unfortunately physics doesn't have an opinion, class-D has high levels of rising distortion at high frequency, it cant pass proper squarewaves at the frequency extremes and these are audible , the top end sounds off to some of us above 10K , its good in the middle but lacks bass and top end air vs good a/ab amplifiers with linear supplies, i can hear it when comparing and listening , so they dont work for me and i don't give 2 cents to ideology regarding topology, if class-D was the best for me , then class-D it is and btw , i have tried 7 different ones and currently own 3 , those are in my home theatre , as i said good in the middle, i'm happy with them , my family too , they use it ...

 

[bart]

I have a 5.0 tube set-up, and I'm very very happy.
I came from Burmester.
My current amps blew my Burmester aout of the water.

I've heard good SET amps with high efficiency speaker: delicious!
That being said, I do love good Class A/B and Class A amps also.

Last year I heard Mola Mola (pre + power amps).
The best Class D I ever heard. It really is in a class of its own I believe.
If you haven't heard it yet, save your breath and go and listen first before you judge on Class D.

 

[Speedskater]

Class 'D' technology can't be restricted to hi-fi amplifiers, in fact hi-fi amps are a very small part of the technology. But overall this 4 decade old technology is now in high demand and is rapidly developing. Some of this new knowledge can be used in new hi-fi amplifiers. We can't generalize using old references.

 

[a.wayne]

I have a 5.0 tube set-up, and I'm very very happy.
I came from Burmester.
My current amps blew my Burmester aout of the water.

I've heard good SET amps with high efficiency speaker: delicious!
That being said, I do love good Class A/B and Class A amps also.

Last year I heard Mola Mola (pre + power amps).
The best Class D I ever heard. It really is in a class of its own I believe.
If you haven't heard it yet, save your breath and go and listen first before you judge on Class D.

Bart,

When you switch from toobs and buy your Mola Mola , i will come and listen , until then save your breath ...

 

[a.wayne]

Class 'D' technology can't be restricted to hi-fi amplifiers, in fact hi-fi amps are a very small part of the technology. But overall this 4 decade old technology is now in high demand and is rapidly developing. Some of this new knowledge can be used in new hi-fi amplifiers. We can't generalize using old references.

Old references !! well most of us have old ears, a class-D hearing aide in a few years may just swing the pendulum ....

 

[Devg]

Old references !! well most of us have old ears, a class-D hearing aide in a few years may just swing the pendulum ....

Or a Class A/AB hearing aid for the newer generation could swing your direction as well

 

[a.wayne]