Hello Ken...
My minds eye was taking me to the service bench in that comment. Perhaps I should have said so more explicitly. What I meant was that when fixing stuff I often hear differences as a result of the repair. But, unless it's a huge difference -- elimination of severe distortion, for example-- it takes test equipment for me to to be sure if it's an improvement.
On live amps in ABX situations, I find most good quality amps sound virtually identical when properly level matched and playing the same source samples. In one case we had half a dozen integrated amps hooked up to a switcher and nobody was able to tell with any certainty which was actually playing.
You may hear a difference if the sum of inaudible differences reaches the threshold of audibility but to hear tiny differences in distortion or minor variations in frequency response, etc by themselves just ain't gonna happen. And especially not at the ear shattering levels most audiophiles listen at.
My minds eye was taking me to the service bench in that comment. Perhaps I should have said so more explicitly. What I meant was that when fixing stuff I often hear differences as a result of the repair. But, unless it's a huge difference -- elimination of severe distortion, for example-- it takes test equipment for me to to be sure if it's an improvement.
On live amps in ABX situations, I find most good quality amps sound virtually identical when properly level matched and playing the same source samples. In one case we had half a dozen integrated amps hooked up to a switcher and nobody was able to tell with any certainty which was actually playing.
You may hear a difference if the sum of inaudible differences reaches the threshold of audibility but to hear tiny differences in distortion or minor variations in frequency response, etc by themselves just ain't gonna happen. And especially not at the ear shattering levels most audiophiles listen at.
Is Tripath 'outdated' was the original question.
Who Knows.. as Tripath folded say what; 15 Yrs(?) ago !?
Damned few oem TA chips.. these days.
Most available Chip amps (of any chip) are Fabrique en Chine and are, despite fanboy claims Komplete Crap.
Befitting their Single digit price tags.
Or double digit $ when cased in a sparkly box..
Buy cheap = Buy twice Or.. if dim .. repeatedly
Who Knows.. as Tripath folded say what; 15 Yrs(?) ago !?
Damned few oem TA chips.. these days.
Most available Chip amps (of any chip) are Fabrique en Chine and are, despite fanboy claims Komplete Crap.
Befitting their Single digit price tags.
Or double digit $ when cased in a sparkly box..
Buy cheap = Buy twice Or.. if dim .. repeatedly
Is this sarcasm? I just want to be sure, because that's the way I want to read it.
Test bench measurements are pretty numbers, but tell the human ear very little with respect to subjective experience. Any single-ended tube amp will show horrendous distortion numbers (1 - 5% THD) on a bench...yet can sound much cleaner and realistic than a "silver face" 1970's Japanese receiver that has 40 dB of negative feedback to obtain a 0.001% distortion rating.
Human hearing responds to amplifier characteristics in ways that are far more complex than neuroscience can even understand today. Measurements SOMETIMES correlate, but more often do not. Go back to that 2% THD of the tube amp...it should sound HORRIBLE from the measurements. But does it?
So far as getting used to a particular amplifier sound, and not recognizing an improvement - based upon what criteria? A measurement? Listening is a subjective experience - if something sounds more realistic to the listener...that is the final arbiter. After 50 years in the audiophile hobby, I can still distinctly hear differences in amplifiers when playing the same source material. I just compared three amplifiers this morning, one of them a Tripath 2020 based, home-built unit. Each amplifier did certain things well, and each did other things not so well. It depended a lot upon source material. The one that gets the overall best score is the one that is usually hooked up.
It's not the Tripath, BTW!
Hello Diogenio...
I'm not going to get into a protracted discussion of subjectivity with you.
Yes those test bench measurements are pretty numbers and interesting graphs and if you know how to interpret them they are very informative. For example I can run up an amplifier on a null test and discover every tiny error in it's behaviour... most of which would be so tiny as to be completely inaudible.
Now if I can do that, how is your hearing going to do any better?
Your ears, and mine, are highly variable, uncalibrated devices. My hearing changes with humidity, air pressure, mood, health, age, tiredness and even my surroundings. To rely upon this as a means of qualitive judgement is sheer folly.
Add in the psychology of the familiar and the tendency to hear what we are told to hear... and the entire notion of subjective audiophile discernment goes right out the window.
Thanks for your reply.
I'm not going to get into a protracted discussion of subjectivity with you.
Yes those test bench measurements are pretty numbers and interesting graphs and if you know how to interpret them they are very informative. For example I can run up an amplifier on a null test and discover every tiny error in it's behaviour... most of which would be so tiny as to be completely inaudible.
Now if I can do that, how is your hearing going to do any better?
Your ears, and mine, are highly variable, uncalibrated devices. My hearing changes with humidity, air pressure, mood, health, age, tiredness and even my surroundings. To rely upon this as a means of qualitive judgement is sheer folly.
Add in the psychology of the familiar and the tendency to hear what we are told to hear... and the entire notion of subjective audiophile discernment goes right out the window.
Thanks for your reply.
Is this sarcasm? I just want to be sure, because that's the way I want to read it.
Kind of ... Almost without fail the people I do service calls for are also the ones their neighbours complain about.
My favourite silly audiophile trick is when they complain about some small problem --say a hiss from their tweeters-- and they have to show it to me by turning their systems up full blast.
I know there are quiet listeners... I am one of them. But, guess what... they aren't the ones having trouble with their systems, or their neighbours.
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Diogenio,
My intention was not to say that the Tripath chips are outdated concepts that just survive on nostalgic feelings. My aim was to say that many objects with an emblematic past have so important aesthetic qualities that they are not left behind though some objective parameters could indicate so.
I just went through the TA2022 datasheet and most specs are comparable to other high class D chip but not fully as good as TPA325X specs.
I could not find it today but I believe to have seen the TA2022 power switch impedance being around 150mOhm while TPA3255 is considerably below 100mOhm. Nothing but a hint that time has been moving on since the conception of the TA2022. My TA2022 has some hiss in particular above 30V supply. But, TA2022 sound is only surpassed by TA3020 sound in the eyes of many audiophiles, not all. And, this is why you should continue using your Tripath amplifiers and I will continue with my Tripath amplifiers because also I find it a very pleasant sound. I am pleased with my TPA3255 as well and choose not to compare it in details to TA2022 sound. They are both very good amplifiers where the TPA3255 probably has better control of the low bass. On the other hand, TA2022 mid-range I find just perfect. No need to declare one winner above the other.
My mentioning of elder emblematic cars as a comparison to modern high performance cars was in response to the more general statement that at a moment it is time to admit that time has left the old ones behind and "let go". That, I see as a general statement and not just pointing at Tripath.
Driving and old Jaguar E or an early Ferrari will aesthetically beat driving a more modern and much more performant car like the Subary Impreza WRX STI, my friends told me. You have a "feel" in these particular old cars that is not found in modern sports-cars. Similar to that a Tripath amplifier may sound better than almost any more modern class D construction.
Even the car with the worst spec-sheet, the Trabi, has far more enthusiasts than many former Nissan and Toyota models that performed much better than the Trabi. The trabi had/has a unique personality which cannot be denied.
I have experienced members on this forum being happy with the sound of a TDA2005 amplifier and a STA540 amplifier. I am very happy to experience that they dared stick to this opinion and did not add "of course it is not like a TPA3255 amplifier". fdenys very recently stated that his cheap LM1875 boards perform very well to his needs - this is what I find encouraging.
Sound quality at the performance level of amplifiers today is such that the subjective impression is very important and more important than technical specifications. Dare conclude which one you find best and do not feel frustrated because others may have a different opinion or your budget does not allow you to buy something more expensive (general remark).
I will remain a loyal supporter of Tripath sound.
To try to reply to your original question: The Tripath specs are not clearly outdated and the question I find of secondary importance. The Tripath sound is arguably among the best which is primary, with a slight weakness in bass-control compared to TPA3255. While the technical specs in general seem to improve with time, the sound quality does not necessarily improve as well.
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I don't know about you, but MY HEARING is the FINAL arbiter of what I experience as a human being. And yes...human hearing is far more complex and sensitive than all the tests you can possibly run.
Let's take your "familiarity" theory out of the equation. A panel of listeners is confronted with two different amplifiers they have NEVER heard before. One is a high-distortion, single-ended tube amplifier - the other a super-low measured distortion, high-feedback 70's Japanese receiver. Want to take bets as to which one sounds less distorted to the panel? There go the beloved specs and measurements right out the window.
When I LISTEN to music I use MY EARS. I don't refer to a set of measurements to tell my brain what I'm hearing! Sad that some people can't trust their own senses.
You can rest assured that those screechy, 1970's Japanese receivers sound better than anything else on the planet. Why? Because they measure better! ;-)
French:
Thanks for summarizing what many people have written, that the Tripath "sound" is still considered excellent when compared to more recent Class D designs. I couldn't care less about the comparative specs - just like I don't care about the chemical analysis of the delicious Coq au Vin I just ate!
Cheers,
I don't want to be accused of calling anyone's baby ugly...just want to point out how the technology has evolved, and why there might be reasons to embrace the newer designs.
The Tripath amps are designed like a Delta-Sigma DAC with a power stage. So read the Wikipedia article on Delta Sigma Modulation, and note the discussion about reducing quantization noise by using second order and higher-level modulation, about half-way down the article. Then look at the block diagram described in one of the Tripath patents issued to Adya Tripathi, which is probably what is used in those products released around 2000.
https://www.diyaudio.com/forums/attachment.php?attachmentid=814562&stc=1&d=1580942204
Then look at what Analog Devices did for the AD1994 chip about 6 years later:
https://www.diyaudio.com/forums/attachment.php?attachmentid=814563&stc=1&d=1580942345
The design of the AD1994 chip was described in an IEEE article that requires a login, but it's worth a read if you know someone with access. It uses the same Delta-Sigma modulation scheme as the Tripath, but with a 7th-order modulator, resulting in greatly improved performance. The AD1994 is obsolete now, but this architecture survives in the SSM3302-series devices, which is what I used for this monstrosity.
I haven't compared a SSM3302 with a Tripath chip and I don't intend to. I'm sure the Tripath sounds fine and is suitable for many applications, but why would anyone use this older technology when devices with better specs and that are easier to use are available? I don't think the Tripath is "ugly"--but I think that there are much better alternatives for new designs.
The Tripath amps are designed like a Delta-Sigma DAC with a power stage. So read the Wikipedia article on Delta Sigma Modulation, and note the discussion about reducing quantization noise by using second order and higher-level modulation, about half-way down the article. Then look at the block diagram described in one of the Tripath patents issued to Adya Tripathi, which is probably what is used in those products released around 2000.
https://www.diyaudio.com/forums/attachment.php?attachmentid=814562&stc=1&d=1580942204
Then look at what Analog Devices did for the AD1994 chip about 6 years later:
https://www.diyaudio.com/forums/attachment.php?attachmentid=814563&stc=1&d=1580942345
The design of the AD1994 chip was described in an IEEE article that requires a login, but it's worth a read if you know someone with access. It uses the same Delta-Sigma modulation scheme as the Tripath, but with a 7th-order modulator, resulting in greatly improved performance. The AD1994 is obsolete now, but this architecture survives in the SSM3302-series devices, which is what I used for this monstrosity.
I haven't compared a SSM3302 with a Tripath chip and I don't intend to. I'm sure the Tripath sounds fine and is suitable for many applications, but why would anyone use this older technology when devices with better specs and that are easier to use are available? I don't think the Tripath is "ugly"--but I think that there are much better alternatives for new designs.
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Another very informative and good post Neil. However, nobody is arguing that the MEASURED performance of the SSM is better than the Tripath. That is clearly not my point. I am a subjectivist, and as such trust my HEARING above all measurements. I'll go back to the high-distortion, single-ended triode amplifier as a prime example of how measurements do NOT always, nor completely correlate with subjective performance.
People listen to LPs all the time...their noise floor is far worse than a Tripath chip. People listen to tube amplifiers as well...and again, the noise floor is far worse than any Tripath chip.
I have 94 dB/W/m speakers that are placed approximately 8 feet from my listening position. Noise from the Tripath 2020? NONE. OK, I'll move a bit closer...NONE. Well, how about I put my ear right up to to the speaker cone? Still - NONE.
I understand how noise outside of the audio band can cause IM products that ARE audible and objectionable, so here again, subjective experiences are the final arbiter. I refer back to the Tripath white papers that indicate extremely low IM products from their modulator. The ONLY question I have, is how does the SSM SOUND when compared to the Tripath technology? If you read back - this is the basis for starting this thread.
To answer your question, why would somebody use an outdated technology when the latest and greatest measured performance is available - it is ridiculously simple to all but an objectivist: IT SOUNDS GOOD. (And in my case, I asked because I happen to have a couple of nice Tripath "kits" sitting in my parts bin, already paid for. Do I go ahead and build them, or is there a SIGNIFICANTLY better SOUNDING (not necessarily better spec'd) Class D to be had nowadays?
Why else would anyone listen to an archaic-technology, hissy tube audio system instead of a dead silent, solid state one? Why an LP instead of dead silent digital system? Perhaps as an engineer, you cannot fathom these choices?
I would have thought that the ultimate goal is what most pleases the ear, and not the spec sheet. That's what it is all about for me, and the means of getting there is wide open to any possible approach, including the "outdated" ones.
Cheers,
Your example actually demonstrates the Familiarity issue... they judge it to be better because it is familiar, not because it actually is better.
This is a horrible trap I see people falling into more and more all the time. As the general awareness of science in society dwindles, magic is beginning to take over...
When's the last time you saw someone actually fix an amplifier by listening only? I've seen dozens of times where they've really screwed them up by trying to... and guess who they run to for help? Yep, the scientist/technician.
What you appear not to "get" is that I listen too. I don't watch my music on an oscilloscope... I sit back in my nice comfy room, set a pleasant volume and let the sound take me away. I also get a lot of repair hints by listening, certain things cause characteristic problems and the first notice is usually by ear.
But I am not so pretentious as to actually believe my ears can out-gun a decent oscilloscope or voltmeter when it comes to understanding the circuitry I employ. If for no other reason than the test gear does not share the many human frailties I noted in my previous post.
Overall my general experience is that people who eschew the science behind technology do so mostly because they don't understand it.
Nice implied slur. How does my MSEE and 45-year career designing military communication electronics sound to you? And tell us about your education that qualifies the implied judgement I do not understand "the science behind technology?"
Now I've really heard it all.
Nice way to take a generalised comment personally.
Did I say YOU don't understand? No I did not.
However, since they stopped making science mandatory in schools, there has been a tendency for people to know and understand less on average than they did even 10 years ago. As that lack of even superficial science spreads more and more people are turning to magical answers to problems that are already very well understood in the scientific disciplines.
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Hi, Douglas,
I mistook what you were intimating. My error. For the record, I want to state that I do not believe in audio magic. These are physical devices, which obey physical laws. So, if the sound is different, then the signal must also, somehow, be different. So, I'm not interested in engaging in yet another useless (I hear a difference - no, you don't) objective vs. subjective type debate either. There is, perhaps, a more intriguing debate to be had.
I very much agree with Diogenio's suggestion that psychoacoustics isn't widely understood, or perhaps taken into account. I've finally come to agree with a view advocated by Vladimir Lamm, of Lamm audio. Which is that a particular behavior of added distortion behavior makes reproduced music sound more realistic, that is, more realistic than if having no added distortion at all!
This isn't merely the presence of euphonic 2nd harmonics, it's more complex than just that. This conclusion also is a bit different from the usual objective vs. subjective debate. High-ish levels of dynamic behavior is an easily measurable set of parameters, yet which appear to improve the subjective illusion of a more live sounding music replay. With the long fruitless pursuit of ever lower distortion figures, more and more frequently coming in under -120dB these days, it's little wonder that null tests and such reveal no subjective difference among low distortion amplifiers. There's essentially no objective difference. This is, of course, a very counter-intuitive conclusion which seems to leave psychoacoustics as an insufficiently addressed and key factor.
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Ooooooo Classic Douglas.
Because you measure stuff and we can't hear it beyond what you can measure and you can't hear it because, confirmation bias, you measured it so you can't hear it?
Personally speaking I could not think of any subjective test subject to crippling falsehood than some bloke with a signal analyser on a mission to prove that my subjectivity is wrong by doing A/B/C/D switching on a range of amplifiers asking me if I can hear the difference as his eyes turn black and roll back into his head.
Fine. Keep it objective.
Diogenio mentions an amplifier with 40dB of negative feedback. Fair enough we might not know where that comes from but...
The Purifi amplifier appears to achieve its performance including extremely low distortion, by implementing an additional integrator in the feedback loop. One of the reasons, or claims, as to why this works is that the additional integrator, perhaps including part of the rest of the loop, is knocked out as or when the loop begins to lose the plot and this is achieved in a 'transparent' manner.
Objectively, and presumably measurably, the words make sense....? Perhaps other people who implement high order loops futz things up. But, of course, you can measure this so if your measurement does not show a problem the problem is not there. So you invent a test for IMD...
Matey Tinman blathers on about his requirement that all amplifiers shall have a monotonically falling set of distortion products. Does Matey Tinman know something or is that his subjective preference. How did he arrive at that preference and identify the reason for it. Does he know the source for that reason?
It's not a brilliant demonstration but the attached picture shows the result of including an integrator in the loop, top, versus knocking that integrator out, bottom. The integrator improves my distortion numbers by up to 20dB, should be a familiar per decade number and you can see that slope.
Otherwise whilst it might not completely satisfy Matey Tinman the distortion products in the bottom plot are falling whilst those in the top plot are rising. Subjectively it would appear that Matey Tinman does not like amplifiers that include the extra stage of integration. Objectively in as much as you can see there is a difference you have to accept there could be a reason for that subjective preference.
Does harmonic distortion distribution matter versus total harmonic distortion. Can you hear the difference between a Major and Minor chord. What if it is augmented or diminished. Then what happens when it's played across different frets.
Objectively from the pictures can you state that you could hear a difference. They certainly measure differently. Subjectively do you think you would hear a difference and would you be able to identify the reason. Objectively can you state that someone else would not be able to notice the difference either with or without you being in their face asking them. Objectively given the structure of the harmonic distortion would you be able to give a subjective opinion as to how the amplifier might sound.
You seem to spend some, a lot, of time blowing off other people's opinions until you become uncertain. Perhaps you might care to listen harder.
End game. Subjectivism wins because people like what they like. Perhaps it's better to try to understand why they like it rather than tell them it measures like dirt and they can't hear the difference anyway because you've got a LeCroy.
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Well put, Fractal. Let me add a little bit to all this:
It was never my intention to lure in hardcore objectivists to this post - those who steadfastly refuse to admit that audio component "sound" cannot always be predicted and/or quantified by measurements. In fact, it is a RARE occurrence that a measurement...ANY measurement...can describe the sound of an amplifier. (BTW, the 40 dB of negative feedback was used in mid-1970's trash Japanese consumer receivers - to aid in winning the THD marketing wars. You know, the 0.001% THD at 200 Watt specs? And we all know how ugly that stuff sounded. But Douglas would likely argue these are perfect amplifiers, because the measurements are superb.).
I am a graduate-degree electrical engineer who's enjoyed a 45-year career designing very complex military communications systems...surely much to the surprise of our objectivist friend. He obviously thought I was some electronics-challenged, science-denier or worse yet...a coupling-cap swapper! I do trust predictive measurements, but only when I am assured they demonstrate a significant correlation to a desired end result. In the case of audio, SOME measurements are undoubtedly meaningful (i.e., power output, output impedance), but for the most part they DO NOT predict the subjective experience of the listener. This is why I call myself a "subjectivist," but this only applies to the audio realm. In my career specialty of RF communications, there was no possibility to be subjective...everything could be measured and quantified. This is simply because human senses and perception were not involved.
There is much for us to yet understand about human beings. There are many diseases for which we have no cure, nor understanding. Similarly, we do not understand everything about our senses, our brains, and the neurological interface between them that results in an "experience." Psychoacoustics is a relatively new field of research, BTW.
My overall audio philosophy is this: rather than delegitimize what a person says he can hear and/or prefers, why not instead say that our ability to measure, and significantly correlate those measurements to our hearing perception - is not yet fully developed? This approach does not invalidate science and engineering, nor does it invalidate the hearing perceptions of the listener.
That's all I will say on this subject.
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Diogenio:
No, I'm not surprised to hear you've got real experience. Not in the least.
From my side we're talking 40 years in electronics in varying roles from home entertainment service all the way to robotic assembly with a good dash of two away radio, office automation, computers and pro audio tossed in for good measure. 35 of those years were spent professionally and if you spent the time to dig back you would even find a couple of patents with my name on them (owned by my employer, of course).
I don't have some monster good, golly gee wiz, low distortion super sonic light dimming system... Right now I'm using a TPA3116 as my main amp, hooked up to a PC with no dac and a pair of entry level Cambridge Audio speakers.
Now sit down and get a good breath... most of the little tweaks and experiments I've done to get my system to where it is have been done subjectively... Yes, by LISTENING and trusting my ears.
BUT...I also recognise that I'm as prone to confirmation bias, familiarity and self-deception as just about anyone else on this planet... so once I get what I want I tend to use science to confirm my work. I may be a bit odd, but I really don't like blowing stuff up... so I check.
Remember my original assertion? I do hear differences but I am not so good at telling if they are improvements or not.
I don't know what people think about those of us who do not run from science, but I can almost guarantee we have more in common with the purely subjectivist crowd than you give us credit for.
Perhaps the only real difference between pure subjectists and objectivists is that us putrid old science mongers actually know how this stuff works and aren't afraid to use that knowledge to advantage.
Are my ears better than yours? Probably not. Especially considering that I took an injury to my left ear while in high school.
Is my system better than yours? I doubt it, but it serves me just fine.
Yes the final arbiter is what we hear --our ears-- but there are lots of times when science can point the arrow at much better hearing experiences.
No, I'm not surprised to hear you've got real experience. Not in the least.
From my side we're talking 40 years in electronics in varying roles from home entertainment service all the way to robotic assembly with a good dash of two away radio, office automation, computers and pro audio tossed in for good measure. 35 of those years were spent professionally and if you spent the time to dig back you would even find a couple of patents with my name on them (owned by my employer, of course).
I don't have some monster good, golly gee wiz, low distortion super sonic light dimming system... Right now I'm using a TPA3116 as my main amp, hooked up to a PC with no dac and a pair of entry level Cambridge Audio speakers.
Now sit down and get a good breath... most of the little tweaks and experiments I've done to get my system to where it is have been done subjectively... Yes, by LISTENING and trusting my ears.
BUT...I also recognise that I'm as prone to confirmation bias, familiarity and self-deception as just about anyone else on this planet... so once I get what I want I tend to use science to confirm my work. I may be a bit odd, but I really don't like blowing stuff up... so I check.
Remember my original assertion? I do hear differences but I am not so good at telling if they are improvements or not.
I don't know what people think about those of us who do not run from science, but I can almost guarantee we have more in common with the purely subjectivist crowd than you give us credit for.
Perhaps the only real difference between pure subjectists and objectivists is that us putrid old science mongers actually know how this stuff works and aren't afraid to use that knowledge to advantage.
Are my ears better than yours? Probably not. Especially considering that I took an injury to my left ear while in high school.
Is my system better than yours? I doubt it, but it serves me just fine.
Yes the final arbiter is what we hear --our ears-- but there are lots of times when science can point the arrow at much better hearing experiences.
Say what?
Look, it's pretty simple really ... there is no sound inside an amplifier or dac or cd transport or tape deck. It's all just electrical signals. In fact it's not sound until it leaves a speaker cone or diaphragm. You can't actually hear an amplifier... which is why test equipment and procedures were developed.
This wedge between subjective and objective audiophiles is beyond silly. Ulitimately we both listen and we both benefit from science.
You can trust me on this one ... your favourite amplifier did not grow on a tree! There's a ton of science going on inside, and you ignore it at your own peril.