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.
@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.
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?
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.
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.
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'.
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.
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.
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.
Personal attacks, insults, name calling, profanity: the last rhetorical refuge of those who have run out of ammo and are throwing the empty gun in desperation.
The moderators are indeed watching this thread. I expect there will be some action taken over the doxxing, profanity, personal attacks, name calling, and other despicable behavior here. Sad and pathetic.
A rather disappointing reflection on some of the regulars here who if they continue in their childishness the mods will likely delete this entire thread.
A rather disappointing reflection on some of the regulars here who if they continue in their childishness the mods will likely delete this entire thread.
see info below -- what is interesting about this troll is the user account dates back to 2000... so i am not sure it is a ’kid’ we are talking about - or perhaps the original user account was hacked... the writing seems alot like the infamous persistent troll that has used various usernames of late such as dannad, cindyment, deludedaudiophile, but perhaps it is someone different... 347 forum posts ’since 2000’ but over 300 of them in the last 90 days -- anyhow, i am sure the mods are monitoring...and hopefully they will take some action
I find the noise floor more distressing than the harmonic distortion. So the graphs could possibly add some insight.
There is a great deal of measurements that could add insight:
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 just find it hard to understand why the manufacturer makes the claim that measurements contain a great deal of information on the subjective performance yet won't publish said measurements. Especially at the price point. These are not unreasonable requests- plenty of other manufacturers publish this data. What’s the big deal? Why the angst and accusations of some nefarious ulterior motive?
This guy is just messing you guys. He appears to hold a grudge. A cursory look at his posts (which is all I can bear to do) shows he is talking in circles and sometimes contradicts himself. He's gotten better at covering his mistakes but in the end, he's just messing with you guys, trying to show how bright he is, which I think, is his main objective.
Assuming that once again you are belittling me with unfounded, unproven, baseless accusations, I can't help but wonder exactly what sort of grudge it is I hold and against who and what proof of any of this nonsense you care to share?
You know, in darkness, it doesn't take much of a light to appear bright...
Ralph-would you be willing to discuss your Class D amp in terms of being true balanced (or not)? Please explain the circuit topology in terms of inputting and amplifying the input signal fully true balanced throughout. And assuming it does not, isn't this a compromise?
Call it Class A-G if it makes you happy but at it's core, the Benchmark was based on a switching power supply which is why it weighs 12.5 lbs.
From S'Phile's coverage of RMAF 2013;
The Benchmark AHB2 amplifier, named in honor of the company's founder, Allen H. Burdick, who passed away just before the show, has a dynamic range claimed to approach 130dB, and outputs 100Wpc into 8 ohms, 170Wpc into 4 ohms and can be bridge to produce 340W into 8 ohms. THD+noise is said to be <–108dB relative to full output at 1kHz. John Siau explained that the THX modules are operated in a mode that gave the lowest noise and distortion rather than the maximum efficiency I wrote about in 2012. A key to the low THD is the use of 0.01%-tolerance resistors at critical points in the circuit. A switching power supply is used, Siau feeling that this was optimal because all the power-supply spuriae will be out-of-band and therefore more readily filtered.
This guy is just messing you guys. He appears to hold a grudge. A cursory look at his posts (which is all I can bear to do) shows he is talking in circles and sometimes contradicts himself. He's gotten better at covering his mistakes but in the end, he's just messing with you guys, trying to show how bright he is, which I think, is his main objective.
All the best,
Nonoise
Perhaps you’re right, but judging other people motivations is usually fraught with some danger.
And if we assume that he is genuine, then his request for metrics seems appropriate in the context of the amp.
You are aware no-one is going to beat Bruno's numbers any time soon. For that reason alone I really don't see what you are so concerned about what measurements we get. If that is the only concern just buy a Purifi and be done with it. The problem I see with that I already outlined.
…
I am sort of surprised to read ^this^…
I find the noise floor more distressing than the harmonic distortion. So the graphs could possibly add some insight.
I'm guessing that "kuribo" is the same person who repeatedly posted very similar comments on another online audio forum using the name "goryu." That discussion was focused on comparing the sonic differences between Ncore modules and Purifi modules. The poster in question stated over and over that personal opinions about sound quality are meaningless. Naturally, statements like that are consistently effective in pushing audiophile "buttons."
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