Class D is just Dandy!

Hi riskymichael,

     I've never had the pleasure of listening to the Rogue Sphinx integrated amp but find it very interesting because of its combination of a tube preamp section with a class D amplifier section.that uses a traditional toroidal power supply rather than a smps (switch mode power supply) like typical class D amps.
     As many class D amp users, including myself, have already stated earlier on this thread, the combination of tube preamps with class D amps has resulted in exceptionally good system performance with a broad range of both tube preamps and D amps.  I can attest to very good results pairing a VTL 2.5L (the standard Chinese tubes being rolled to a set of NOS Mullard tubes) with my first class D amp, a Class D Audio SDS-440-CS that was my main amp for a few years and also has a toroidal power supply. 
     Obviously, Rogue is well aware of this synergy of tube preamps with class D amps and it's likely a major reason why your Sphinx sounds so good.
  
     The subject of whether there's a performance benefit to using the more traditional toroidal power supplies rather than the newer switching ones in class  D amps is less clear.  I now use 3 class D amps in my combo 2-ch and ht system, 2 stereo amps with toroidal power supplies and a pair of mono-blocks with the newer switch mode power supplies.  I notice all have the usual class D attributes of very low background noise, low distortion, high detail levels from top to bottom, very good dynamics and being very accurate and neutral overall. 
      The mono-blocks are more expensive,use different class D power modules and are much more powerful than both stereo amps.  I do notice the monos are even more detailed, even smoother and more life-like in the mid-range/treble and portray a more solid and stable soundstage illusion which I attribute mainly to the different class D power modules.  I also notice the monos have more powerful dynamics, especially on better 24/96Khz files recorded direct to digital, which I mainly attribute to the significant increase in power and perhaps the power modules and smps, too. 
      However, I'm unwilling and unable to claim whether the difference in power modules or power supplies are responsible for the clear improvement in dynamic range of my mono-blocks. 
     Without comparing otherwise identical versions of our amps, one version with a toroidal and the other with a switch mode power supply,  I don't think we can determine which performs best. But even this comparison would not address the relative degree that the power modules and power supplies affect amp performance.  
     The only things I can state with certainty is that my smps monos are more efficient and run cooler than my toroidal stereo amps. 
 
 Tim

I'll second tsugury's recommendation of the Rogue Sphinx.  I've had one in my system for a couple of years now and continue to be impressed with its performance, especially considering its very modest cost.  I hesitated considering this amp, as I've previously found Class D amps to be somewhat sterile sounding and fatiguing over time.  Not Rogue amps.  I believe that this can be attributed somewhat to modern Class D modules, but also to Rogue's tube preamp section and their use of a beefy linear power supply.  Quite musical and dynamic!

I’d take good class D over most class a/b amps in a heartbeat. Class. d uses modern switching technology to compete effectively with good class A but can deliver more sound per $$$ when needed due to its efficiencies and is more practical for most especially when lots of power and current are called for as is often the case with modern smaller less efficient speakers with greater bass extension.. Its that good now and still getting even better as the technology continues to improve.

Class a/b is old compromise technology. Class D may put it to rest totally someday. I had a class G amp once. Yuck. Class D stomps that. Class A is a different story as are tube amps which still provide a truly different way to deliver distinctive results.

" This is all great discussion but doesn’t it come down to your ears, budget  and preference for the love of music."

     Yes, bluesy41, it does all come down to what equipment enables one to most enjoy reproduced music in their rooms based on their ears and budget. 
     I think it's generally known and accepted that great sounding systems can be assembled using tube, class A and the best class AB amps.  But these amps are not only very expensive they are also very large, heavy, electrically inefficient and emit a lot of wasted energy in the form of heat.  However, nobody can accurately claim that they don't sound very good.
     An underlying theme of this thread has been the revolutionary and egalitarian nature of good class D amps.  More Individuals are now able to attain 'hi-end' sound quality at an affordable price.  The fact that these amps are relatively small, lightweight, electrically very efficient and emit little heat are all just additional benefits to the very good sound quality
    In the not very distant past when good class D amps didn't yet exist, those not able to afford the steep price of the best amps were limited to finding an affordable class AB amp they liked.   It still comes down to your ears and budget, class D has just expanded everyone's options. 

Tim 

@georgehifi 

Yes I’ve been using the 4ohm tap and it sounds glorious. 

Cheers 

I'm using Devialet (Class A/D Hybrid) after many years of Krell, Pass Labs, BAT, Mark Levinson and McIntosh ownership, and I have no plans to go back to using legacy (Class A/B) amplifiers. The size, weight, efficiency, aesthetics and sound of the new technology is awesome. 

Very understandable, as your Maggie 2.7's like most Maggie's has a very benign 4ohm load that doesn't need that much current, just watts.
You should use the 4ohm tap for best control, penalty is you'll loose wattage compared to the 8ohm tap. 

Cheers George 

Hi scott_w,

Congrats on your soon to arrive DAC amp. You're fortunate you were able to audition 2 different class D amps in your system before you purchased. Typically, you’re required to purchase the amp and then audition it during an in-home trial period. But I suspect companies have a very low % of amps returned through these programs.
You named 2 of the 3 main common sonic qualities I’ve experienced with good class d amps: a very neutral flavoring and effortless dynamics. The other main sonic quality that is typically clearly evident in good examples of class D amps is how quiet they are. Music seems to emerge from a dead silent background that seems to enhance the musical impact and details perceived.
Welcome to the Great Sounding Green Amps Club.
Please post back with your impressions once you’re able to audition for awhile.
Tim

I just ordered a Cherry amp, from digital amplifier company, arrives in 3 days. My local buddy brought his over for a jam. Another buddy loaned me NCore / hypex 400 monos AND Rowland 525 monos, all in the last month. Lotsa Class D for me lately on audition.

Anyhoo, the modern Class D coming out now are amazing. Lightweight, barely uses juice, runs cool, all that. But the sound! Neutral, effortless dynamics due to the huge power. If you've not heard a higher end D amp in a rig, go try to.

Anyhoo II, I'll post my Cherry thoughts soon I reckon, later this month. I'm sure y'all on edge of seat in anticipations.

Bel Canto Design REF600M was the Absolute Sound co-amp of the year and second place Stereophile for amp of the year, behind the $99K Boulder. The Bel Canto Black EX amp is even better. 

But again that’s preference. I was mislead by dealer and the internet that led me to believe that Maggie’s required brut power it wasn’t until I decided to let my ears be the judge and bought a class A amp that puts out a whopping 95wpc. I’m not saying class D is bad I’m just saying that for my system and listening preference I went class A.  

What was this 95w linear Class-A amp??

Cheers George

This is all great discussion but doesn’t it come down to your ears, budget and preference for the love of music. Budget and listening preference will ultimately be the deciding factor.

Yes, oh my Goddess, it’s like we are twins...

If person A has a budget of 50 - 60k he’s not looking at Class D period in of story.

Oh, wait, what????? I disagree. Just because I have x amount of dollars doesn’t mean I’m going to spend it. My goal is not to spend $x, it’s to spend as little of $x as I can and be happy with it. If I’m happy with $x/10 then that’s all I will spend.

To do this however you have to give up the notion that price is any sort of arbiter of performance. I no longer believe this is the case. If you feel that the market value expresses your desire, then make yourself happy. :)

Best,

E

This is all great discussion but doesn’t it come down to your ears, budget  and preference for the love of music. Budget and listening preference will ultimately be the deciding factor. If person A has a budget of 50 - 60k he’s not looking at Class D period in of story. I went down the class D route a few years ago when I first purchased my Maggie’s and told I needed a amp with at least 300wpc. So I ended up buying an Audio Research DS450M monoblock amp that put out 600wpc into 4ohm load. At the time for 12k and looked like a pretty good way to go, but after a few years of trying to recreate the sound that made me fall in love with the Maggie’s I knew the amp was my problem. Could it play loud an emphatic- yes, did my Maggie’s produce an audible sound - yes, was it musical to my ears, I would say no. But again that’s preference. I was mislead by dealer and the internet that led me to believe that Maggie’s required brut power it wasn’t until I decided to let my ears be the judge and bought a class A amp that puts out a whopping 95wpc. I’m not saying class D is bad I’m just saying that for my system and listening preference I went class A.  

Anyone experience IQ Audio M300 monoblocks?

Mapman,
     Your last post was an excellent summary of the current state and future possibilities of class D amps.  I agree with all of it.

" 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."

Hi sfseay,
     While I generally agree with you, I think many readers of these class D threads are considering trying one of these amps for the first time and base their decisions largely on the impressions of people like us who already have experience using them in our systems.

     I know I was reading class D threads for this purpose when I first began considering trying a class D amp about 5 years ago.  
     But that was an earlier time in class D's evolution and, as I recall, there was a more even balance between praisers and detractors at that time.  If I'm not mistake, I believe mapman was one of the early adopters praising class D but there were also many claiming class D would never be a good choice for anything other than a sub amp.
    I finally just decided to try one and decide for myself how the current good examples of this technology performed in my stem.  I thought it'd be more useful to start developing my own experience with class D amps than to rely on others' impressions.  I was thinking just as you stated: If I liked it then I'd keep listening.  
     Perhaps what you consider irritating and excessive praising of class D is just considered useful positive feedback to some still considering whether to try one of these amps in their systems.

Tim

"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?

"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.

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.

 "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  

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

George, its more complex than that

You keep saying it Ralph, it’s the main cause for me, and even noted SS amp manufacturers like the highly regarded Solution amps deigner/owner ect.

"Cyrill Hammer (Soultion Amps) "if you want to have your product performing at the cutting edge it is not possible with today's known switching technologies. In order to come close to the performance of the best linear design we would need high-current semiconductors that provide switching frequencies of several MHz or even GHz."

I know your developing your own Class-D around present day technology.
We all know hiend isn’t how it used to be, and we all have to do what we can to make ends meet.
I wish you luck on your venture into Class-D, but to me and others like Cyrill it’s too soon yet to take the plunge.

Cheers George

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

" 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 ...  "

Hi cleeds,
     Sorry, I'm not understanding your point.
     I really didn't go to great lengths to classify the class D detractors I've  read responses from since I became interested in this technology about 5 years ago.  Just a few minutes recollecting, a few classifying those I recall from Audiogon and other forums and a few minutes detailing my thoughts.
     In retrospectively considering and gauging the totality of posts I've read about class D in the past 5 years, I have little doubt that supporters of class D are in the majority and detractors in the minority. 
     I have no doubt that various forms of bias were evident in many of the class D detractors' posts.  Here are some of the major forms of bias I recall:
1.  Bias in the form of claiming class D was only good enough for subs even though they'd never auditioned a good recent class D amp in their system. 
2. Bias in the form of claiming their current amp would outperform a class D amp even though they'd never actually auditioned one in their system.
3. Bias in the form of claiming the majority of class D amp's switching frequencies  were too low and negatively affected sonics in the audible range even though they provided no scientific or even anecdotal evidence to support their claims.
4. Bias in the form of claiming class D amps were inferior because the Damps they auditioned in their systems failed in their opinion to outperform their much more expensive tube or class A existing amp.

    There are more forms of bias I recall but I'm short on time right now.  
    Yes, I do consider class D detractors overall a minority and do consider many of their posts I've read over the past 5 years to be biased in some form.
   Your stating this and adding a "Hmmm..." does not amount to a coherent statement.  Please clarify.

Thanx,
  Tim   

George, its more complex than that.

The reason Technics is switching so fast is to reduce distortion. The filter has little to do with it. At their speeds, the inductance of the speaker is sufficient. So their filters are mainly concerned with preventing RFI.

Keeping the switching speed high is important for resolution, and decreases distortion. The problem is that the faster you switch, the more time has to be alloted to allow the devices to turn off before its mate can be turned on.

This waiting time is called 'dead time' and increases distortion. so there's a bit of a catch-22: the more you try to decrease distortion by increasing switching speed, the more dead time you have to have and that increases distortion.

Technics' solution is by using Galluim Arsenide devices that no-one else can get, which are a lot faster (and can switch considerably faster than they are actually being switched in the amp). The reason they are doing this is to minimize dead time, and so have created one of the lowest distortion Class D amps made.

We're taking a different approach. We found a way to eliminate dead time altogether. This allows us to switch at a lower speed and still get lower distortion, or switch at a speed Technics is doing it, without having to use devices that are as fast.

It is the notion that Class D switching speeds are the cause, and that someday they’ll be fixed that irritates me.

If you guys are going to point a finger, get the whole story right.
It’s not the switching speed per se, but the output filter that has to try to get rid of it without any detrimental effects down into the audio band that’s the problem.
  
That’s why Technics with their $20k SE-R1 class-d has striven for double the switching speed, so then that output filter can do it’s job properly without much detrimental effect down into the audio band.

Cheers George

I have had Class D amps from Classe (Sigma 2200i), Auralic (Merak Mono Blocks), PS Audio (HCA-2) and currently use a Lyngdorf TDAI-2170.  The Lyngdorf and Classe amplifiers were designed in-house and didn't use off the shelf modules.  Don't know if that is good or bad.

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.

If you like Class D, great, but perhaps some of you fanboys can tone it down.  Many of us are tired of hearing your opinions, and it is pretty obvious you are biased so your opinion doesn't mean a lot to the community at large.

" IMHO I find class D amps to be less musical then Class A amps. I tried several class D amps and to my ears they lack the midrange, rhythmic
space, texture, air and less involving compared to good Class A amps.Something just seems to be missing musically to my ears. But to each his own. I'm not a audiophile snob I just know what makes my finger snap, head nod and foot tap."

Hi bluesy1,
     I understand.  I think it's a good and healthy thing that there's such a wide variety of amps currently available that individuals can tailor their system sound by choosing an amp that matches their sound preference.  
    Sound preferences are as unique like fingerprints and snowflakes.
    Your snowflake, bluesy1, seems to fall into group#3 from my last post.
     I'm glad you found a system sound you prefer with your class A amp.
Enjoy,
  Tim

Different strokes for different folks, as is always the case. I owned many amps over the years and my newest Class D amps are the best. Saved me from going the tube amp route. Benefits are greatest for those that favor smaller speakers with extended bass, or similar power and current hungry speakers which is the norm today for most affordable high quality speakers. If you run a tube amp with the right speakers to match and are happy probably no need to consider Class D. Otherwise you may be missing out big time! Beside the top top notch performance and sound you save space with both amps and speakers and your power bill and overall TCO is minimized.

noble100

'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 ... there seems to be a small group of class D detractors .. there are so many class D amp listeners and owners ...  class D detractors and naysayers are best not considered as a single group but as a collection of smaller groups ... their comments being more biased  ... group#3 is definitely the most frustrating since they offer no scientific evidence ... I'm not aware of a single experienced class D user/owner, including myself, who has ever heard any sonic anomalies that they claim exist. I think it's safe to state that any logical person would consider their theory as being thoroughly and completely debunked ... Just the fact that the majority of humans are incapable of perceiving these sonic anomalies but a small minority of the population can indicates an allergic reaction to class D by this minority ... individuals in group#3 can be extremely frustrating and annoying. But perhaps we should be more sympathetic to these poor afflicted souls.

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 ... 

" 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."

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.  
     Nevermind that the current leading expert on class D, UcD and Hypex NCore inventor Bruno Putzeys, has stated the current switching frequencies are not too low.  Nevermind that there is absolutely no scientific evidence supporting the claim that current switching frequencies are too low and cause audible sonic anomalies.  Regardless, there seems to be a small group of class D detractors that still claim that current switching frequencies are too low and negatively affect sonics that they're able to detect.
      I've spent more time contemplating this subject than it likely deserves as well as why there are so many class D amp listeners and owners, just like you and I, who perceive no sonic anomalies at all while an apparently smaller group claims to hear some and dismiss class D technology as a result.
    My current thinking, based on multiple threads discussing the amps and technology over the past 5 years,  is that class D detractors and naysayers are best not considered as a single group but as a collection of smaller groups such as these:

1. Those that have never actually listened to a good D amp in their system but simply parrot other critical comments they've read previously.  This group can typically be identified by their comments being more biased toward whatever amp type they own and use than biased against class D. 
2. Those that acknowledge the strong points of class D but consistently mention the same perceived flaw of switching frequencies being too low  This group can usually be identified by a lack of scientific support and a lack of even an anecdotal description of the claimed flaw's sonic affects.
3.  Those that actually do try out class D amps in their system but claim that 'something is missing from the sound' and decide to just continue using their existing amps.  This group can usually be identified by statements containing sentiments about how they really wanted to like class D but liked the sound of their existing amps better. 
      Their existing amps are often high quality and expensive tube and class A amps that are very large, electrically very inefficient, emit copious amounts of heat into their rooms and color or flavor the inputted signals in some preferred manner.  This group is typically and understandably seeking a more electrically efficient amp that doesn't raise the temperature of their rooms but still performs at a high level.
      The 'something missing in the sound' they have difficulty pinpointing is predictably the coloring and flavoring of the inputted signals that is avoided by design by most good class D amps in favor of a much more neutral approach that emphasises faithfully amplifying inputted signals more attuned to the audio ideal of an amp as 'a straight wire with gain'. I have no issue with this group preferring their more colored amps.
     Of my 3 general groups above, I agree that group#3 is definitely the most frustrating since they offer no scientific evidence of support because none exists, are very vague about the sonic manifestations they theorize exist in the audible band due to the switching frequencies being too low and I'm not aware of a single experienced class D user/owner, including myself, who has ever heard any sonic anomalies that they claim exist.
     I think it's safe to state that any logical person would consider their theory as being thoroughly and completely debunked.
     Just for fun, however, let's assume they're correct and all the thousands (millions?) of very satisfied class D amp owners/users are wrong.  Let's assume these sonic anomalies actually do exist in the audible range due to switching frequencies being too low. 
     If this was actually the case and the truth,  I would expect medical experts, neurologists and hearing care specialists to inevitably classify the ability to hear sonic anomalies in class D amps as an auditory/cerebral affliction, malady or syndrome. Just the fact that the majority of humans are incapable of perceiving these sonic anomalies but a small minority of the population can indicates an allergic reaction to class D by this minority. 
      I agree that individuals in group#3 can be extremely frustrating and annoying. But perhaps we should be more sympathetic to these poor afflicted souls.  Just as being lactose intolerant prevents those afflicted from enjoying a delicious glass of cold milk, being class D intolerant prevents those afflicted from enjoying the delicious sound of a good class D amp.

Love,
 Tim 

This back-n-forth between class D and class A reminds me of the raging debate in the late 70's / early 80's over V8 engines and the up-and-coming 6s and 4s. Nobody, back then, could have imagined a 6 or lowly 4 producing the horsepower and torque of today's engines. IMO today's class D amps are the 4s and 6s of the audio world. Soon, and very soon, conventional amplifiers will go the way of the 426 hemi; the 427 corba jet; and the big block Chevy. Some will hang on to their Hemi 'Cudas, Gran Torinos, and Malibu Super Sports. And some of us will park our classics and embrace the Focus RS and the like. Regardless of which camp you're in, profits and competition drives innovation. Like it, or not, class D is here to stay. And one day class D will give-way to newer-tech. Personally I'm happy to be in the cusp of changing technology. I too am hanging onto my well-regarded, class A amp...but I'v also embraced class D and am happy. That said, if class D is not your cup 'o tea then so-be-it; being happy is the objective. But for those of you who are curious, take advantage of the plentiful home-trial offers...and ask those of us who gone before you about our experiences.

erik_squires

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.

That sounds more like an opinion than a prejudice to me.

@cleeds

I’m perfectly OK with you not liking a class of products. That’s not what I’m talking about.

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. It is the boogie-man aspect of this particular line of reasoning that I am against, or that Class D still has anything left to prove to be among the best sounding amplifiers available.

Like what you like. Spend money to make yourself happy. But I'm done with arguments like "Bagostino amps are better because they have no feedback" or "Class D switching noise will never let it be as good as ..."

Those arguments are tired as can be.

Best,

E

erik_squires

I still here the same fear obfuscation and doubt thrown at Class D amplifiers, without meaningful research behind it ... With zero objective evidence of such a thing. This is a vague, moving goal post. I've heard a number of Class D designs that equaled or better very expensive Class A designs.

I'm not asking you to like any particular class D design, nor am I saying all Class D amps are going to sound as good as any linear amp with particular speaker. I am suggesting this is thin techno-fear without research or experience behind it.

That you disagree with what some say here doesn't mean that they are guilty of obfuscation or are fearful. And while you claim otherwise, you are indeed asking us to like Class D because, as you state, " I've heard a number of Class D designs that equaled or better very expensive Class A designs."

It's not because of "thin techno-fear" that I don't like Class D amps. I just haven't met one that I like. To be fair, I'm not looking real hard, either. I just don't see any reason to replace the amplifiers that I have and which work very well in my system.

As Paul McG says in the video - we're just talking about stereo here. So why such a need to "vent?" Why should the preference of others disturb you so?

I still here the same fear obfuscation and doubt thrown at Class D amplifiers, without meaningful research behind it.

One of the biggest: Class D can't be as good as (blah blah) until the switching frequencies are above x Hz.

With zero objective evidence of such a thing. This is a vague, moving goal post.  I've heard a number of Class D designs that equaled or better very expensive Class A designs.

I'm not asking you to like any particular class D design, nor am I saying all Class D amps are going to sound as good as any linear amp with  particular speaker. I am suggesting this is thin techno-fear without research or experience behind it.

Yes, there is ultrasonic noise. So what? All amplifiers have noise. I have seen and heard zero evidence of this being audible. Yes, there will be amplifiers that will move the switching frequency from 450kHz to higher. So what? At what point, exactly, will it be high enough? What measurements, exactly, and what threshold of those measurements, will satisfy you that they have reached audio nirvana?

You do not have to like Class D. That's fine if you do not, but I've read encyclopedia's worth of hogwash on this particular subject here and elsewhere on the net. It's like a scam diet, which proclaims that x protein is the root of all evil. Buy my new book and I'll show you how to avoid and heal your gut... blah blah blah.

I also want to point out, I've been listening to Class D amplifiers since the 1980s. They were horrible, despite overall reasonably good specifications. So I'm not saying you should listen with specs, but rather, find the specs that correlate to audible effects. 400mV of 500kHz noise is measurable, but not audible, and my amps sound a lot better or as good as several Class A amps with all the speakers I've heard. I would gladly trade the size, cost and efficiency in exchange for a measurement that has zero bearing on my experience.

Sorry.  had to vent.

Best,

E

Paul McGowan of PS Audio recently released a really good video on the future of Class D audio.  

https://www.youtube.com/watch?v=98QQ43qgzbg

I'm using a PS Audio HCA 2 with the Cullen mods and I love it. 

I auditioned a variety of amps in my home - a high powered ARC tube amp and a Pass Class A amp at the same time I had the PS Audio.  I think I may have liked the Pass amp about as much as the PS Audio, but I'm inclined to keep my gear turned on all the time I didn't think I'd like the extra heat and energy usage.

Time and innovation march forward so I'm sure there are others that are better, but I'm not feeling any urge to upgrade at this point.

I haven't seen much discussion of the NAD M22 outside of general discussion of the Hypex nCore modules, but I've had this amp for the better part of a year. It replaced an Ayre V-5xe which put out too much heat for the hot southern summers I have to endure. While perhaps it doesn't have quite as much depth as the Ayre, it has incredible bass definition and control, a wide soundstage, and a sense of liquidity, propulsion and flow that the Ayre definitely didn't have. It has a pristine clarity and neutrality without seeming anywhere near harsh, dry or boring, and the dynamics are thunderous. I really couldn't ask more from an amp. Considering I see the M22 going for roughly 55% off the MSRP around these parts, I don't think there's a better performance bargain for power amps on the used market.

There isn't time to read all of this thread, so my apologies if it's already covered the Red Dragon S500, but I've had that for almost two years and am really pleased with it.  Sound is detailed, balanced across the frequency range, bass is deep and articulated, mid-range is clear, treble is also clear and realistic though I sometimes think it might show a little more sparkle.   Certainly it's well ahead of the Class AB monos I had previously, and they'd been well recommended.  

The main partnering equipment is an Esoteric X05 SACD player, Townshend Allegri preamp, and B&W 804S speakers. 

I don't doubt that there may be better Class D power amps.  Some will be better because of their design and the quality of their components.   It's also possible that some Class D modules are better than others.   Living in Britain I don't get much opportunity to compare the sound of different systems.  I did hear one of the first NORD NC500 power amps (it's only an hour's drive to where they are made), but the demo wasn't very successful from my point of view - mainly to do with the circumstances and not necessarily a criticism of the amp itself.   Buying the Red Dragon was something of a risk because although I could return it within 45 days, I wouldn't get the import duty back and there's be expensive carriage costs.   But it's been highly successful and I'd probably have to pay a lot more to get something that performs significantly better; though in five years' time, perhaps, when things have moved on a lot, better quality may be available more cheaply.

Nearly forgot about my second system.
Linn Classik all in one which uses a 70wx2 class d amp and sounds pretty darn good for what it is and I have no desire to replace it with anything

I did try a pair of bel canto ref 500m monos a couple of years ago but for reasons I think mostly associated with the other gear I quickly moved on!

However in my ht rig the move to class d amp was a massive step forward in every way.
Replaced my Emotiva amps with a tiny single nuforce power amp making a claimed 150w x8, only using 7 channels for my 7.1 system.
The emotivas claimed 300w x2 and 250 x5, not quite sure where they were hiding those horses as the nuforce creamed them in every aspect.
dynamics, action, dialogue, sheer volume were vastly increased with the nuforce.
and now I have one tiny little box which has replaced two behemoth amps that were sucking juice and pumping heat.

I will at some stage give a pair of mono class d amps a whirl in my main rig again I am very sure!

MDE.. I'm not an audiogon regular so PMng seems to be escaping my abilities! Feel free to send from your end :)

Thanks MDE.. gives me something else to read about. His approach seems a little different and his units carry a bit of weight to them (Makes class A/B people like me feel more comfortable!). I'll PM you fo rthe other info!

@jdavis37 Not all Class D manufacturers use third-party amplifier modules. Check of Digital Amplifier Company. He designs his own Class D amps, or at least that's what he says (see website.) I own a pair on his Maraschinos and I love 'em. I also have some experience with other brands you mentioned. But I'd rather not speak of that here. PM me if you want more information. And I am not affiliated with, nor compensated by, Digital Amplifier Company...just wanted to get that said.

Heat and weight are not a concern for me, either. But I can see where those 2 things might be appealing for some. I won't lie in that I am struggling some to be really attracted to Class D for now. The technology seems to be changing rapidly whereas Class A/B at the least is mature. Same reason why in general I do not prefer paying for a DAC built in to the preamp unless the maker has a way for future upgrades. Dropping $5K or $11K for a pair of monoblock Class D amps only to see a much improved amp board emerge in 2 years would hurt my financial feelings. My spousal unit is very good with accepting my expensive hobbies to  a point. Course if that $5K Class D amp already produces sound quality I find superior to every Class A/B amp I can find in the same price category then it may well work. But am giving consideration to some SST equipment (Son of Ampzilla 2 and Theobe II) as well which will not cost as much as some of the Class D options I am looking into! Course maybe I should just stay with my current setup... it is good and is now free :)

I do though see some advantages regarding heat generated (if that is a concern.. for me it isn’t) and size/weight. They offer a ton of power in a small mass versus trying to heft around a 90 pound Class A/B amp or an even heavier (with less power) tube amp.

I see my system as something I want to get the very best from, and if I have to compromise and pay for it in less efficiency so be it.

I wouldn’t buy a Ferrari put low octane fuel in it, stick cross-ply tires on it and drive it like a granny just so I could say I’m being kinder to the environment.

But Class-D amps with the promises of higher switching frequencies technology in the future, may become all they need for me to jump camp, then my current amps will become door stops or boat anchors.

Cheers George

I do though see some advantages regarding heat generated (if that is a concern.. for me it isn't) and size/weight. They offer a ton of power in a small mass versus trying to heft around a 90 pound Class A/B amp or an even heavier (with less power) tube amp.

Thx George.My only experiences are with Class A/B mostly and some Class A. I have heard tube amps but never owned one, and in past thought of Class D as mostly sub type amps (my ignorance). I started reading about the newer Class D amps and the price range is fairly broad. I also recognize pricing is not always linear with cost (whatever market will bring). But it is hard to see how 2 amps using the same identical amp board can vary in price so much which of course begs my question of why.

If the cost of the parts, including cases, connections, etc. as well as the actual amplifier modules is a lot cheaper than their Class A/B counterparts, and their sound quality is close but it results in an overall cost reduction for the buyer than I would be more encouraged. It is difficult for me to hear much of this stuff without buying it. Not many nearby sellers.

But I am probably missing something along the way. If the more expensive units are adding proprietary mods that would be one thing. Otherwise it starts sounding like a prettier case, etc. is adding a lot of cost!