Today I picked up my Atma-Sphere Class D Amps. These aren’t broken in yet. And they are simply amazing. I’ve listen to a lot of High End Class D. Some that cost many times what Atma-Sphere Class D costs. I wasn’t a fan of any of them. But these amps are amazing. I really expected to hate them. So my expectations were low. The Details are of what I’ve never heard from any other amps. They are extremely neutral. To say the realism is is extremely good is a gross understatement. They are so transparent it’s scary. These amps just grab you and suck you into the music. After I live with them some and get them broken in. And do some comparisons to some other high end Amps Solid State, Tubes and Class D’s, also in other systems I’ll do a more comprehensive review. But for now, these are simply amazing amps.. Congrats to Ralph and his team. You guys nailed on these.
I understand your point of view re: keeping this thread going for the appreciation and discussion of atmasphere's amps. I never intended to post to this thread as I won't own the amp but reading it from time to time caught my attention as to the cruelty displayed by kuribo in his relentless highjacking of the discussion and denigration of Ralph's amp as well as his character, in what he thinks is a veiled and clever manner.
That there are some here who've fallen for kuribo's tactics is not my concern. As anyone can see from his post above, he's of the impression that he's got the upper hand and is now playing the victim and using that for cover while attacking Ralph and his amp. Using memes like "doxxing" and feigning injury is part of his M.O. He's used it throughout this thread.
So yes, the mods will be made aware of this, shortly.
We still have no way to accurately predict what an outcome will be for a randomly chosen individual listening to reproduced music- will he prefer a tube amp or class d? Again, the fact that there are successful class d amps and tube amps is proof that there is no consensus subjective choice.
In time, the tube amps will be gone. Not because of a lack of tubes but because they've been eclipsed and people will wonder why they go through the hassle when subjectively better sound is available at less cost. That hasn't happened yet simply because class D has taken some terrible missteps in the last 20 years.
1. Distortion versus frequency: flat or rising?
2. Frequency response vs load: independent or dependent?
3. FFT vs frequency: level of even, odd, 2nd, 3rd, later harmonics?
4. Distortion + Noise versus power for different loads: increasing or decreasing? Level?
5. Power stage efficiency vs power at different loads: comparison between GaN and regular mosfets
With people making claims of this amp’s superiority, I see no issue with asking for some proof. When the manufacturer states that there is a lot about an amp’s subjective performance that can be gleaned from the measurements, I say please show us.
I have stated that some of the above are important parameters to look at. I've also stated that our amp has some of those properties. That the distortion does not rise with frequency isn't something that needs to be shown; its a simple statement of fact (you could have surmised the truth of this by looking at my comments about feedback, Gain Bandwidth Product and of course distortion vs frequency). You either accept it or you don't- much like you might if you saw a graph on our website- which you might believe or you might not. The bottom line here is trust. You don't trust other's opinions since you don't trust their ears to work the same as yours despite the fact that all ears work the same despite your remonstrations. It is apparent though that you are embrace the subjective experience as anyone else here.
If you'd like a tip to improve credibility here are two:
First, refrain from attacking others even when they attack you.
Second, you would do yourself well to drop one of two stories about yourself, either that measurements are the only thing to look at, or that you have to try it for yourself. You can't take both positions at once since others see a contradiction even though you may not see it.
We still have no way to accurately predict what an outcome will be for a randomly chosen individual listening to reproduced music- will he prefer a tube amp or class d? Again, the fact that there are successful class d amps and tube amps is proof that there is no consensus subjective choice.
You wrote:
"In time, the tube amps will be gone. Not because of a lack of tubes but because they’ve been eclipsed and people will wonder why they go through the hassle when subjectively better sound is available at less cost. That hasn’t happened yet simply because class D has taken some terrible missteps in the last 20 years."
Your reply sidesteps my statement, that is, that we can not accurately predict what an outcome will be for a randomly chosen individual listening to reproduced music- will he prefer a tube amp or class d?
Tube amps disappearing because they are a hassle and there will be subjectively superior choices seems a stretch-been hearing that for years. They said that about vinyl. And yet, both are still here and have their rabid supporters. Perhaps they will quit making tubes completely at some point but as long as there are baby boomers and nostalgia, they will survive. And if they do disappear, it will probably encourage someone to make fake tube amps. Wait, someone already is!
You continue to talk about the similarity in how we hear. Yes, the physiology of our senses is similar. The important distinction is that while we all have similar physiology- the transducers that input external stimuli- there are differences in functionality between individuals due to age, slight differences in physiology, etc. This means that while we all "hear" the same, the input to the brain, as empirical studies have shown, is not the exact same- there is a variation. More importantly, while we might all "hear" the same, we don’t all interpret the stimuli in the same way. Research has shown that the interpretation of perceptions is a complex function of experience, mood, and an untold number of biases. Thus, while we all have similar physiology, and "hear" similarly, we don’t all interpret what we hear in the same subjective way. This is proven by the wide range of differing products, each with their own fans. It’s also the reason why there are salt and pepper shakers on tables at restaurants.
You talk about masking of high harmonics. Wouldn’t it be preferable to not have to use 2nd/3rd harmonics to mask higher harmonics? I would prefer an amp that had all the distortion below the threshold of hearing rather than using such a trick to mask them. I suppose that if one were trying to mimic the "sound" of certain tube amps, this could be considered a feature rather than a bug.
1. Distortion versus frequency: flat or rising?
2. Frequency response vs load: independent or dependent?
3. FFT vs frequency: level of even, odd, 2nd, 3rd, later harmonics?
4. Distortion + Noise versus power for different loads: increasing or decreasing? Level?
5. Power stage efficiency vs power at different loads: comparison between GaN and regular mosfets
With people making claims of this amp’s superiority, I see no issue with asking for some proof. When the manufacturer states that there is a lot about an amp’s subjective performance that can be gleaned from the measurements, I say please show us.
You wrote:
"I have stated that some of the above are important parameters to look at. I’ve also stated that our amp has some of those properties. That the distortion does not rise with frequency isn’t something that needs to be shown; its a simple statement of fact (you could have surmised the truth of this by looking at my comments about feedback, Gain Bandwidth Product and of course distortion vs frequency). You either accept it or you don’t- much like you might if you saw a graph on our website- which you might believe or you might not. The bottom line here is trust. You don’t trust other’s opinions since you don’t trust their ears to work the same as yours despite the fact that all ears work the same despite your remonstrations. It is apparent though that you are embrace the subjective experience as anyone else here."
I disagree. You have painted broad strokes and made claims but not delivered on the proof. You are a manufacturer in a hobbyist forum with a self-interest in a product. I believe it reasonable to hold you to a higher standard. When someone is charging 4 times what a market leading product costs, never mind that it has half the output power, I think it unreasonable to just say "trust me". With other manufacturers offering complete measurements I find the "trust" argument woefully insufficient. That is certainly your right but I think it poor form in this venue.
You have mischaracterized my statements regarding my trust of the opinions of others: it has nothing to do with how our ears work and everything to do with differences in perception/taste, never mind the obvious issues of basing anyone’s judgment of an amp in their system and room rather than in my own. Nearly every amp on the market has those who like it, and those who don’t. Why would any rationale person base a $5000 purchase decision on the opinion of someone on an audio forum? No, I don’t value the subjective opinions of others on equipment but I do value my own and would never expect others to place any value in my subjective opinions . In this very thread we have seen negative comments about certain products that have had wide success in the market with many who praise the product.
You wrote:
"Second, you would do yourself well to drop one of two stories about yourself, either that measurements are the only thing to look at, or that you have to try it for yourself. You can’t take both positions at once since others see a contradiction even though you may not see it."
Again, a mischaracterization of my position. Your mistake is claiming I am taking the positions as you have defined them: I have never ever said measurements are the only thing to look at. I have said over and over that measurements offer insight into the engineering, design, and objective performance of an amp, and as such they have value. I use measurements to screen out products that don’t meet my engineering, design/construction, and objective performance standards. From there, those which make the cut get further consideration and audition. I thus use both objective and subjective criteria. I see no contradiction in using both criteria in the purchase decision. In fact, I know many rational people who do the same, whether it is audio equipment, automobiles, computers, etc.
You are not alone in misrepresenting my view. In fact, it seems so commonplace here that I almost have to believe it is being done on purpose in some twisted way to provide a point of attack and the "go back to ASR" smears.
Lastly, I would like to address your comments about Purifi amps and the use of various input buffers to "tailor sound" by several manufacturers. You made a statement to the effect that "if you can hear the opamps, there must be an issue with the design".
First of all, many of these amps, with different opamps, have been tested and while all the results I have seen show that the performance of the amp with these various third party buffer/op amps isn’t quite at the level of the stock Purifi buffer and opamp, the measurements do not show any differences which would normally be considered audible in any way. In other words, if there were some issues with the design, one would expect significant differences.
Reading through the various opinions on these amps, some prefer the Weiss opamp, some the Burson, others Neurochrome, and others have said that the stock Purifi buffer is their choice. Some describe one op amp one way, another describes the same op amp another. Measurements show no differences which can be considered to be audible. They may all be "hearing" the same way, but their brains clearly do not seem to be interpreting the input in the same way. We see this same thing with cables and all the wacky tweak products- none of them can be shown in most cases (poorly designed cables, for example, would be an exception) to do much of anything, yet some people swear they turned their system up to an 11, others say they hear nothing. Previous experiences, mood, biases, go a long way to explain this perception paradox, This is why I find no real value in subjective comments regarding equipment on forums such as this.
Finally, I wish you all the best with your product. You seem to be thoughtful, sincere, and committed to your craft.
Your reply sidesteps my statement, that is, that we can not accurately predict what an outcome will be for a randomly chosen individual listening to reproduced music- will he prefer a tube amp or class d?
Actually it addressed it directly. In due time 'he' will prefer a class D amp as it will sound better, making the tube amp not worthwhile for all its extra hassle. That is what I said earlier. BTW this phenomena is already occurring.
You have painted broad strokes and made claims but not delivered on the proof. You are a manufacturer in a hobbyist forum with a self-interest in a product. I believe it reasonable to hold you to a higher standard. When someone is charging 4 times what a market leading product costs, never mind that it has half the output power, I think it unreasonable to just say "trust me".
This statement is false. Its not me you need to trust. Your trust issue is that you aren't aware that others can hear the same things you do- you don't trust their hearing since you think it can't be the same as yours. In the past you've suggested not in so many words that perception and taste are the same thing. At some point you will be disabused when you drop that story.
First of all, many of these amps, with different opamps, have been tested and while all the results I have seen show that the performance of the amp with these various third party buffer/op amps isn't quite at the level of the stock Purifi buffer and opamp, the measurements do not show any differences which would normally be considered audible in any way. In other words, if there were some issues with the design, one would expect significant differences.
IMO this is a classic example of how the industry in general does not recognize some fundamental properties of the ear brain system. Its as if research of the last 40 years is being ignored. The ear is a lot more sensitive than you think it is and so these differences are more significant than you think. Here's what that's about: the ear uses higher ordered harmonics to sense sound pressure. The ear has about a 130dB range which is pretty crazy. This means that distortion product 100dB down is audible if its unmasked. The ear assigns tonality to all forms of distortion (for example, higher orders are assigned 'harsh and bright'). BTW this latter fact of human hearing has been know for well over 90 years and should not be controversial to anyone but the uneducated.
So what might be considered 'insignificant' if often quite audible. Audiophiles have been dealing with this problem for well over 70 years now; its why we have to take stuff home to hear it for ourselves. This is the inconvenient truth of audio.
I use measurements to screen out products that don't meet my engineering, design/construction, and objective performance standards. From there, those which make the cut get further consideration and audition. I thus use both objective and subjective criteria. I see no contradiction in using both criteria in the purchase decision.
Well you're not alone in that. Everyone I know of does the exact same thing. The contradiction is in the way you've stated your position in the past. Thus I've revised my assessment; you're mistrust isn't others hearing so much as what meets their 'engineering, design/construction, and objective performance standards'.
How can you begin to know what someone will prefer? How can you begin to assume that you know what "better" means to someone else?
I answered that question several times on this thread. You deny its reality and I can't help that. So let's put it a different way- It really helps to keep up on research FWIW...
And yet it’s your product and you are the one making claims about your product and not providing measurements, saying "You either accept it or you don’t- much like you might if you saw a graph on our website- which you might believe or you might not." That sounds to me like "trust me". Asking and expecting me to trust some stranger is even worse.
And it isn’t, as I have said, that I don’t trust their hearing, it’s that I don’t trust their perceptions/taste.
What is a claim I've made? Just so we're clear on this. FWIW I've not asked anyone to 'trust me'. I was pointing out with that comment that such is an issue- its one thing for a manufacturer to put up information on a website. It's quite another when someone else does it. As a result I don't see the point; we already know what the amp does. The question now is really to our customers- do they think that the amps do what we said they would? My experience of the last half century is that if they don't think so they won't be customers.
And yet it’s your product and you are the one making claims about your product and not providing measurements, saying "You either accept it or you don’t- much like you might if you saw a graph on our website- which you might believe or you might not." That sounds to me like "trust me". Asking and expecting me to trust some stranger is even worse.
And it isn’t, as I have said, that I don’t trust their hearing, it’s that I don’t trust their perceptions/taste.
Its not by job to educate although apparently I do that with all the time I spend writing... Your position seems to arise out of you don't accept that the sense's perception and taste are two entirely different things! The former is autonomic and the latter conscious. So far as your writing is concerned, you conflate the two, which is a common mistake.
Not a lot of amps with distortion 120db down that would be said to have a "design issue".
Exactly!- but I said 100dB down IIRC and I do consider that an issue. Most of the numbers guys I run into think maybe -85dB to -90dB is acceptable. I know better, but good luck trying to convince them of that! So I don't bother.
It’s true the best measurements are those done by qualified and trusted independent parties. Maybe that will pop up somewhere soon. Meanwhile hope to give the Atmasphere amps a listen soon maybe at CAF.
You may have already covered these issues earlier in this thread, but could you please explain a little more about the following two issues with regard to your Class D amps?
1. I noticed that the switching frequency for your amp is 500 kHz while several other GaNFET amps use a higher switching frequency. Did you decide that 500 kHz represented a "sweet spot" for switching frequency in your design? Does the choice of higher rates have unwanted side effects that can adversely affect sound quality?
2. What factors entered into your choice of a toroidal power supply rather than a SMPS? What number and size of capacitors did you use in the power supply and how did you decide on the amount of storage needed?
@ricevsYes, Ralph is correct and the others are wrong. Ralph solved the unsolvable with his original OTL design. He worked on his design for years until he solved the technical challenges. Who are you to question his credibility? Who are you to post a meaningless piece of excrement $300 dac as your proof of concept that op amps must be rolled? And to do it in a thread that the OP created to discuss Atmasphere class d?
You know, there was a time not long ago when people like you and the other obnoxious poster would just go elsewhere rather than to purposefully disreepect someone like Ralph. He has been here since the beginning of Audiogon, answering questions, never hawking his own gear, just providing honest and forthright answers to those trying to understand something. And then an amateur tweaker like you comes along and disparages Ralph? The other guy too? You are both pimping your own agendas but why did you pick this thread and Ralph?
You two should be ashamend of yourselves…you have no credibility and just because you’ve soldered a few times and liked the results does not make you qualified to disparage Ralph or his design. If you have a shred of integrity, you would have least listened to the class d Atmasphere amp before beginning your false sermon.
I respect Ralph for so many things and count his incredible patience with kuribo here among them. But in my heart of hearts I wish he’d spend the time developing an even more affordable stereo version of these monos (hint hint) rather than using that otherwise valuable time trying to reason with a troll who can obviously never be reasoned with. Better to realize that 98% of the people here greatly respect you and your work while kuribo gets 2% on both counts so why waste your time? Again, why would a guy who puts no faith or credence in anyone’s subjective opinion (save his own) even be here where everyone looks for, values, and shares subjective opinions? I suggest again that we just let kuribo keep typing away in his mother’s guest room or basement that he probably shares with her sewing machine and creepy dresses and ignore the useless drivel that’ll only become more useless, ridiculous, and annoying. Easier said than done, but I think if we put our heads together we can do it. Let’s Go!!!
Reading through the various opinions on these amps, some prefer the Weiss opamp, some the Burson, others Neurochrome, and others have said that the stock Purifi buffer is their choice. Some describe one op amp one way, another describes the same op amp another. Measurements show no differences which can be considered to be audible. They may all be "hearing" the same way, but their brains clearly do not seem to be interpreting the input in the same way. We see this same thing with cables and all the wacky tweak products- none of them can be shown in most cases (poorly designed cables, for example, would be an exception) to do much of anything, yet some people swear they turned their system up to an 11, others say they hear nothing. Previous experiences, mood, biases, go a long way to explain this perception paradox, This is why I find no real value in subjective comments regarding equipment on forums such as this.
@kuriboif the nueroshrome, purifi (etc.) opamps all measure the same, then what do you attribute people listening preference to? Or is it a psychological preference/bias?
Sad that most of you realize this so late when I said that few pages ago.
Remember, a troll will first bring YOU ALL to his level and then beat you through his experience of trolling.
Folks need to refrain from responding to trolls, however tempting it might be. Check his history on this site. Join date, responses to topics, etc. He had an agenda and you all fell for that. Hopefully some lessons learned.
I find it interesting that Ralph is predicting the eventual demise of tubed power amps. Aside from the supply chain issues and embargos with Russia I think they will be around for quite some time. Now I do like some of the newer class D amps including Ralphs. I think that the goal has been to get as close to the sound of a tubed amplifier with more efficiency and reduced cost. I recall reading an interview of that Bruno P fella and he said as much.
Wish there were more GaN integrated though. Trying to cut back on boxes.
Great question, I do not think many dealers are keeping much stock anymore. The last few years it seems that you had to wait for an appliance to come in from the distributor. Even pre pandemic I can remember having to wait a week or two.
Talk about audio (however defined) on this esteemed forum. There are many issues to explore and many wonderful contributions. Address the many questions raised.
What is with this with character assassination? That is what inexperienced and puerile teenage girls do at school when they have a crush on some boy.
I ordered the monoblocks on May 27 and received them on Aug 16, so a bit under 3 months for me. Definitely worth the wait. I was quoted a 3 month wait and it came in just under that.
@j-wall - This is going to be a bit of a round-about answer:
I've been a SET fanatic for several years, primarily 45 and 46 SETs. I just love the presense and intimacy that those SETs provide with my 98dB + speakers.
I have been on the lookout for a Class D alternative that could provide or at least approach that SET sound that I have fallen in love with. After watching a video (don't recall which) where Ralph was describing his Class D monoblocks and based on his outstanding reputation, I ordered a pair. This was a leap of faith for me as it was the most that I had paid for any piece of audio gear except for speakers.
I've had them in place now for a little over a month and will say that I'm not dissappointed. They are certainly the closest to the SET sound that I have heard from a solid state amp. They are not quite up to the SET sound that I was looking for, but they come very close.
No question, Class D has come a long way and that will likely continue to improve.
Coincidently, while waiting for the Atma-Sphere amps to arrive - a friend recommended that I try another Class D stereo amplifier which is Paschal based. I won't mention the name here (since this is a thread on Atma-Sphere Class D).
Is it as good as the Atma-Sphere, probably not, but it is very very good and I plan to do an A/B test with them in the near future.
Neither of these amps will replace my 45/46 SET amps, but they are outstanding alternatives. I'm sure there are many other excellent Class D amps out there, but I have not had the opportunity to hear them
I have always expressed my appreciation for Ralph's contributions on this Board. Don't believe me? Look at my previous posting history and you will see for yourself. But up until now I never saw such promotion-as here-of his own product.
In time, the tube amps will be gone. Not because of a lack of tubes but because they've been eclipsed and people will wonder why they go through the hassle when subjectively better sound is available at less cost. That hasn't happened yet simply because class D has taken some terrible missteps in the last 20 years.
How much hubris can a man possibly have to make such a pronouncement! This man has solved the problems leading to 20 years of "terrible missteps" of all that came before him?
How is this pronouncement any different than those of the dumb prognosticators who declared vinyl dead once Philips-Sony came out with CD players in 1982 or so? Vinyl is far more of a "hassle" than tubes.
Who is Ralph to declare that his subjective opinion of the sound of his own product is absolute? Ralph will no doubt diplomatically respond that he is not just referencing his own Class D amp. If so, than tell us Ralph which other Class D amps are you declaring to be subjectively better than the best tube amps other than your own?
Ralph, how can you possibly tell the thousands of us with tube amps and preamps that if we only gave your Class D amp a good audition we would come to the realization that your Class D amp is subjectively superior? How can you then, in good conscience, even offer your tube amps for sale?
As I type this I am wearing a mechanical watch, a Carl Bucherer Scubatec that costs the same as Ralph's amp, needs an expensive cleaning and lube every six to eight years, does not have the accuracy of a five dollar cheap digital watch, and has to kept on a watch winder or re-set once the mainspring's power reserve runs out. By analogy this would be the same as someone like Ralph stating that I should or will eventually realize that my preference for mechanical watches is folly.
And Ralph, you have responded to virtually everyone else's questions and statements including those of the bizarre troll, and yet you won't respond to mine asking-earnestly- whether your class D amp has true balanced topology and if not, the sonic compromises if any?
You may have already covered these issues earlier in this thread, but could you please explain a little more about the following two issues with regard to your Class D amps?
1. I noticed that the switching frequency for your amp is 500 kHz while several other GaNFET amps use a higher switching frequency. Did you decide that 500 kHz represented a "sweet spot" for switching frequency in your design? Does the choice of higher rates have unwanted side effects that can adversely affect sound quality?
2. What factors entered into your choice of a toroidal power supply rather than a SMPS? What number and size of capacitors did you use in the power supply and how did you decide on the amount of storage needed?
The allure of a higher switching speed is increased loop gain which allows for more feedback. The downside is that you need to have deadtime and that value is a constant that does not change with switching frequency. Distortion thus increases with the switching frequency, so I guess in a way there is a sweet spot. The other issue is the faster you switch, the crazier the stray inductances become which can result in parasitics at some pretty high frequencies!
We used a toroid simply because a SMPS really should be custom-built for its application. There are a good number of advantages to SMPSs such as voltage regulation and oddly, lower noise (wasn’t the case 30 years ago!). But you have to be careful about current limiting issues which can really be a thing if the amp is subjected to lower impedance loudspeakers and in particular ones with crazy phase angles. So its easier to simply use a toroid.
And Ralph, you have responded to virtually everyone else’s questions and statements including those of the bizarre troll, and yet you won’t respond to mine asking-earnestly- whether your class D amp has true balanced topology and if not, the sonic compromises if any?
Sorry- that was an oversight on my part. If you don’t know, we’ve been pushing balanced operation longer than anyone else in high end audio; our MP-1 was/is the first balanced line preamp ever made for home use. Its not something we backed away from in the class D!
Who is Ralph to declare that his subjective opinion of the sound of his own product is absolute? Ralph will no doubt diplomatically respond that he is not just referencing his own Class D amp. If so, than tell us Ralph which other Class D amps are you declaring to be subjectively better than the best tube amps other than your own?
:) as Capitan Kirk once said ’Who do I have to be?’
Seriously though we think our class D sounds better than our tube amps although we’ve not done serious comparison with our bigger tube amps. We think our tube amps sound better than most other tube amps so its a simple logic statement at that point. But I really wasn’t commenting on our amp in particular; I was commenting on the fact that class D offers a technique (rather than specific amps, although there are class D amps out there that get very nice comments such as the AGD and Orchard) wherein this is possible, since it is very easy to develop the Gain Bandwidth Product that will allow the designer to support an enormous amount of feedback at all audio frequencies. Prior to the recent evolution of class D this really was extremely difficult until the mid 1990s with solid state and impossible with tubes.
That is why we never ran feedback with our OTLs, since keeping distortion vs frequency linear across the audio band is pretty important if you want the amp to not sound harsh. That’s easy in a tube amp if you don’t run feedback! Our OTLs have as few frequency poles as you can get in a tube amp and even with them we ran into issues with their phase margin. IOW, very difficult to prevent oscillation even with a carefully designed feedback loop if running large amounts of feedback. Conventional amounts were no problem but had all the downsides that have given feedback a bad rap in high end audio.
Class D offers a way around that problem. We started with zero feedback prototypes but found out quickly that a zero feedback class D amp has to have a very stable oscillator for the triangle wave, else you get a high noise floor as the oscillator drifts in frequency. With self-oscillating designs this source of noise is eliminated.
How can you then, in good conscience, even offer your tube amps for sale?
Funny thing about that, people still want them and don’t always believe things that I say, as we’ve seen on this thread. You get used to that over time :) But I can see a day when our tube amps become custom order only or gone altogether.
This man has solved the problems leading to 20 years of "terrible missteps" of all that came before him?
No. Class D has been an evolving tech for quite some time. Clearly others have gone before us and it is they that solved the lion’s share of difficulties, Bruno Putzeys in particular. In a way I think we were lucky in that in our design it worked out that the primary distortion sources tended to produce lower ordered harmonics, so although the overall distortion is much lower, the actual distortion signature otherwise would make you think you’re looking at a tube amp.
how can you possibly tell the thousands of us with tube amps and preamps that if we only gave your Class D amp a good audition we would come to the realization that your Class D amp is subjectively superior?
If you look back you’ll see that I answered that question several times on this thread for kuribo. He seemed unable to accept the answer, as best I can make out because he thinks the autonomic senses and taste are the same thing.
One thing that is a bit of a hurdle, now that you bring it up, is the higher output impedance of zero feedback tube amps in particular. This causes some ’warmth’ the class D won’t have because the tube amp will likely have a slight FR error in the bass associated with the impedance rise with most speakers have in this region. The ear interprets that extra bass energy as a bit of warmth and it causes the perception to tilt slightly away from the highs.
Once you compensate for that (on my speakers I used pink noise to set them up with each amp comparison since the driver levels are independently adjustable), then you see what is really afoot.
Ralph, I think you missed your calling. You should have been the US Ambassador to North Korea, China, or Iran. You have side-stepped your bold declaration that tube amps, the entire category bar none, are on their way out. But that is fine. I will not say another word in this thread and I truly wish you the best. I am confident enough in my high-end audio world to not let a different opinion-even yours-bother me any more than it has (which was relatively minor). Perhaps you could be so kind as to look me up three, five, or ten years down the road and tell me when my ARC Ref 150SE and ARC Ref 80 power amps have been rendered value-less. on the market so I can inquire of my accountant if I can declare a depreciation deduction.
@fsonicsmith- I guess time will tell if Ralph's assessment pans out, but I'm essentially with you none of my tube amps are going anywhere unless I purchase some other tube amp, or the powers to be come breaking down the door to mandating its cart-off.
How much hubris can a man possibly have to make such a pronouncement! This man has solved the problems leading to 20 years of "terrible missteps" of all that came before him?
People have been jumping all over @kuribo,which as @noske described earlier in a puerile fashion, with Troll and Fan Boi descriptions. But this seems like more like what they are describing.
When someone has 40 year in the industry, and brought balanced XRL to home audio, it is different than PS Audio YouTube videos.
One can only be so humble and demur, and honesty is not exactly overdoing it in a self promotion way.
I am not sure how Ralph can respond and communicate any better than he has? He certainly does much better than I can do in the sense, but I am also not an expert in the field.
. Who is Ralph to declare that his subjective opinion of the sound of his own product is absolute? Ralph will no doubt diplomatically respond that he is not just referencing his own Class D amp. If so, than tell us Ralph which other Class D amps are you declaring to be subjectively better than the best tube amps other than your own?
He also said that if people like the absolute best numbers and even lower distortion, that Bruno has those in the Purifi Class-D that they sell.
Perhaps you could be so kind as to look me up three, five, or ten years down the road and tell me when my ARC Ref 150SE and ARC Ref 80 power amps have been rendered value-less. on the market so I can inquire of my accountant if I can declare a depreciation deduction.
We can also roll in ARC with Purifi and Atmasphere, but that does not change the fact that they are running a business and have decided that a move to Class-D is a direction that they want to be poised for.
if one asks hard questions, or makes statements that are not appreciated they are referred to as Trolls and Fan Bois, and if they respond civilly then they are referred to as an ambassador.
But that is fine. I will not say another word in this thread and I truly wish you the best.
@atmasphere Thanks for the helpful comments in response to my questions about the choices of switching frequency and power supply for your Class D amps.
Thank you for your patience and great explanations. With regard to the high-lighted statement below:
That is why we never ran feedback with our OTLs, since keeping distortion vs frequency linear across the audio band is pretty important if you want the amp to not sound harsh. That’s easy in a tube amp if you don’t run feedback! Our OTLs have as few frequency poles as you can get in a tube amp and even with them we ran into issues with their phase margin. IOW, very difficult to prevent oscillation even with a carefully designed feedback loop if running large amounts of feedback. Conventional amounts were no problem but had all the downsides that have given feedback a bad rap in high end audio.
Would you please expound upon your statement: "keeping distortion vs frequency linear across the audio band"? I am afraid I don't quite follow.
Also, since you mentioned that your Class-D amp uses a fairly large amount of loop feed-back, which helps keep THD down, would you please inform what your amp produces by way of Transient Intermodulation Distortion (TIM)? In that light, since there are many different methods of measuring TIM, and also since it's very difficult to measure, would you please inform which method(s) were used?
You have side-stepped your bold declaration that tube amps, the entire category bar none, are on their way out.
@fsonicsmith That was not my intent. To my understanding I've not side-stepped this issue at all:
IMO power tubes are on life support- even in the guitar industry class D has been making significant inroads in the last couple of years. Its clear that any manufacturer of amplifiers now has to contend with class D technology in a way that they did not a decade ago; in particular manufacturers of tube amplifiers will find their market shrinking dramatically over the next ten years. The reasons for owning tube amps (the 'sound') is being heavily eroded by advances in class D technology; any manufacturer that ignores this does so at their own peril.
Would you please expound upon your statement: "keeping distortion vs frequency linear across the audio band"? I am afraid I don't quite follow.
@atulmajithiaIn order for an amplifier to exhibit the same smooth character as the music itself, in order to not sound bright, distortion must not rise with frequency. This is one of several characteristics needed to allow the amp to be musical and not bright. If a tube amplifier is zero feedback and has sufficient bandwidth (not including the output transformer if one is present) then this really isn't a problem. Of course the designer needs to pay attention to other issues but distortion vs frequency is pretty important.
The ear is very sensitive to higher ordered harmonics since it uses them to sense sound pressure. It also assigns a tonality to all forms of distortion and higher ordered harmonics get the value of 'harsh and bright'. In addition distortion products occurring in the Fletcher Munson region (3-7KHz) causes distortion in that range to be more easily heard.
TIM is a product of an amplifier having high feedback but also has part of the amplifier outside of the feedback circuit so unable to compensate for certain types of distortion. An example might be the base of a transistor in a differential pair, wherein the input signal is applied to that transistor while the feedback is applied to the base of the transistor's mate. This is a common circuit in many solid state amps over the years. Class D amps of the self-oscillating variety (like ours) don't have that kind of input circuit and so avoid this problem.
I agree with Ralph regarding future sales of tube amps. Sure, some will always want to own one, but sales will erode dramatically over the next 10 years. Seems like a rather reasonable statement. Innovation in Class D amplification will continue and magnificent sounding options will be introduced at ever increasing speed delivering sonic improvements many felt impossible just a year or two ago.
@atmaspherebacks up his words with his actions. That makes for a strong case. We will see.
About 12 years back I was on the brink of going with tube amps to get the sound I wanted but decided to look forward and try the newer evolving technology (class d amps) rather than backwards. I have great faith that advancements in technology move things forward. Been a Class D amp fan ever since. Still have a tube preamp sitting idle currently but never took the tube amp plunge. class D did the job better for me. No looking back now at this point. Kudos to Ralph for being forward thinking and having always had a great appreciation for good things past.
I agree with Ralph regarding future sales of tube amps. Sure, some will always want to own one, but sales will erode dramatically over the next 10 years. Seems like a rather reasonable statement. Innovation in Class D amplification will continue and magnificent sounding options will be introduced at ever increasing speed delivering sonic improvements many felt impossible just a year or two ago.
I said I was done but this is such nonsense. Amplifier design and amplifier performance has been dictated by the limitations of loudspeakers. There is no perfect amplifier because there is no perfect loudspeaker. "Magnificent sounding options" and "Sonic improvements many felt impossible just a year or two ago". What flowery and prosaic language! That's a good one. The euphonic nature of tubes happens to suit the limitations of many loudspeakers in a manner that solid state often fails. Charles Hansen wrote about this towards the end of his life. https://www.youtube.com/watch?v=9L0k3-cporQ&t=5s Think of an amp as a complimentary solution to a problem elsewhere in the chain, not the source of the problem and impediment to sonic bliss.
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