A Bright Shining Lie…Why ignoring an inconvenient truth is stifling system performance a blog from Roy Gregory
- Thread starter Elliot G.
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It all sounds like the bassackwards equalization stuff audiophiles love so much. Engage some cumbersome, painstaking equalization process like moving speakers instead of having bass and midrange controls on the speakers or amp. Compensate for the room anomalies of fixed, one-size-fits-all crossovers, generated in the maven's lab, with an endless array of expensive cables substitutions.
These are 'Sisyphus' endeavors.
Any room is going to have multiple permutations that are impossible to scope out in any meaningful data-certain way. There is such a thing as 'good enough, shut up and enjoy the music'.
As far as critics are concerned, they are religious priests who make their bones with a variety of catered superstitious invented authorities. So, have fun with the prose, but throttle back on the belief that something scientific is going on.
These are 'Sisyphus' endeavors.
Any room is going to have multiple permutations that are impossible to scope out in any meaningful data-certain way. There is such a thing as 'good enough, shut up and enjoy the music'.
As far as critics are concerned, they are religious priests who make their bones with a variety of catered superstitious invented authorities. So, have fun with the prose, but throttle back on the belief that something scientific is going on.
When i posted Roy’s article I was aware it would foster a discussion however this forum has really turned. into the i’m correct and everyone else is wrong or worse once again. I’m cool with different opinions and methods but I am not cool with the rest . Your personal background and technical expertise has never and i repeat never been shown to be infallible in producing a perfect or even a guaranteed better sounding device.
It truly has been the cornerstone of the designers in our industry. They have come from
everywhere yet the most negative always seem to be the Specs first engineering crew.
This is truly tiresome and to be frank downright boring and in this case and good dose of disrespectful as well.
The i’m right your wrong and if you don’t agree you are an idiot needs to go away it’s just become way to prevalent.
It truly has been the cornerstone of the designers in our industry. They have come from
everywhere yet the most negative always seem to be the Specs first engineering crew.
This is truly tiresome and to be frank downright boring and in this case and good dose of disrespectful as well.
The i’m right your wrong and if you don’t agree you are an idiot needs to go away it’s just become way to prevalent.
Nothing sudden other than switching from triode OTL amps with low/no feedback and high output impedance (I won’t say Class A because they are for sure not to full rated power) for 35 years to a switching class D amp with tons of feedback and near zero output impedance.I've always been interested in feedback; there's nothing 'sudden' going on. I've also always been interested in connecting the dots between how we perceive sound vs what we measure. For most of my life, the devices didn't exist that would really make the application of feedback practical in an audio power amplifier without causing brightness and harshness due to distortion generated by the feedback itself. You really have to get over about 30dB and that has to be at all audio frequencies before you really start to get around that problem (so while this is all control theory of course you do still have to take the human hearing perceptual rules into account). One of the issues of course is that the typical feedback node (the cathode of a tube for example) is not linear and so the feedback signal is distorted before it even can do its job. That's why you need so much feedback. In tubes this is literally impossible due to phase margin issues (oscillation) and that pesky GBP... Futterman made an OTL that boasted 60dB of feedback but that value fell off dramatically at higher frequencies, causing distortion to rise with it. We didn't want that; we wanted the distortion vs frequency to be a ruler straight line and the distortion spectra to be unaltered with frequency; hence zero feedback OTLs.
IMO the Halcro seemed to sound so sterile because of its distortion spectra- its not enough to merely have low distortion, since the ear converts all forms of distortion to a tonality; also the ear is keenly sensitive to higher ordered harmonics on account of using them to sense sound pressure. The reason an SET sounds so rich is thus also due to distortion spectra. The difference is how the 2nd and 3rd harmonics are able to (or are not able to) mask higher ordered harmonics. An SET is quite good at this despite having more higher ordered harmonics than almost any modern solid state amp. In most cases this means you lose low level detail but you gain some musicality. I like to have both, which is why we made/make OTLs- you get more detail; easily heard (and not surprisingly the distortion is lower too) and now our class D.
As you know I've been building zero feedback class A triode fully differential balanced OTLs for nearly 50 years. If you are not running feedback you need bandwidth like crazy (one of the failings of SETs, where the OPT is the bandwidth limitation but it does help that upstream there is bandwidth). We've not measured the slew rate of our class D but it is certainly higher than that of our tube amps (which have an output section risetime of about 600V/usec) as the output devices effortlessly switch at 60MHz. The class D has bandwidth (and distortion spectra) similar to a lot of lower powered SETs; it begins to roll off around 20KHz (but with about 3-4 orders of magnitude less distortion and a very nice 1st Watt). There is a lot of correction at that frequency that isn't available to an open loop design. Most of our prototypes were open loop FWIW; they demonstrated that the technology was worth pursuit.
Its true that many modern opamps have lots of GBP; very nice since as long as you don't ask more than about 20dB out of them you don't run into problems with feedback falling off at higher audio frequencies (I'll leave their design to others since you can buy them for just a few dollars...).This was not true decades ago; if you try to replace older opamps in vintage guitar pedals you find out real quick that the opamps in them were part of the 'sound' which really shouldn't happen with opamps. In theory.
We've looked into current feedback strictly for fun, since there are no speakers based on current drive its impractical. If you want to make a viable product you have to employ voltage drive since 99% of all speakers made are based on voltage drive. The other 1% are power drive and exist only in the high end audio market. Any zero feedback tube amp is a power source device (although imperfect). That 1% of speakers plus some crossover examples from the voltage camp has been a large enough market that we've made a career of it. Its nice to finally have an amp that can address the greater market without having to compromise the resulting 'sound'.
'Space electronics'... delightful
Never mind they almost certainly sound totally different… not just that the new amps improve upon the strengths of your old designs but a complete different character…as would be expected based on the effects of design choices. Where once you touted the current source paradigm as superior and frowned on the more common (and primarily SS) voltage source paradigm, now you go on about GBP and having MOAR feedback… Never seen such a 180 degree about face in my whole audiophile career from a designer, except the BelCanto guy.
Given that neither technology is sonically invisible, I struggle how such a switch can be rationalised on sonic terms. I know all the tech reasons why you think this new Class D is great but I have heard this story before and then laughed at it when I heard what they touted. Can’t imagine sn OTL lover going for it…
The late Paul Weitzel of Tube Research Labs fame, and later infamy, went through a similar progression, from a hardcore tube devotee making Magnus-Opus massive over the top reference tube equipment, to his solid state Samson amplifiers and in the end Class-D amplifiers. I assume that as he got older in age and began to suffer from health issues working with 12 pound boxes was more to his liking than 400 pound steel chassis.
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So you expected me to give him a pass? When Mr. Gregory is trying to exult a flawed approach, while deriding the traditional A/B approach as “stupid”, his word not mine?
By the way, why don’t you ask John Atkinson what he thinks of Mr. Gregory’s novel evaluation methodology when you drop off the Wadax Reference dac for measurements.
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When I finished Fremers, I made the comment, I should go through every reviewers space and ensure the electrical infrastructure is correct. That was never going to be approved.
?? I must not understand the question. Our MP-1 and one of our amps does have that 'transfer function'. Power amps must not have too much gain if they are not also higher power. Power amps by themselves don't have enough gain to work with a lot of sources (digital being the sometimes exception). So it sounds like you're asking why we don't make an integrated amp using our OTL approach and the answer is the product would be far too large and cumbersome. Plus- why would you when our class D can do the job and not sound appreciably different?
I have to imagine that you've not paid much attention to what I've previously written on this matter elsewhere. Our class D has a distortion signature very much like our OTLs and similar to SETs in that the 2nd and 3rd harmonics are the predominant distortion products- this because the non-linearities of the encoder scheme and the deadtime both impose lower ordered harmonics.
Early prototypes of our OTLs employed feedback. The original MA-2 had switchable feedback. So that goes back about 45-50 years. Not sudden- just sudden to your awareness of what I might be doing in spare time
(FWIW dept.: 'power source' not 'current source'.)The difference between the class D and our OTLs has been described by a number of people independently of each other but in a strikingly similar fashion- the difference being that the class D is slightly more transparent in the mids and highs but otherwise has the same relaxed character of the OTLs; the easiest difference is heard in the bass (and this is coming from OTL customers of ours...)- since the class D acts as a voltage source and the OTLs do not the bass difference is on that account. In most cases this means the bass is better too.
The reason this seems to be such an about face is because for most of my life the devices needed to really apply the kind of feedback needed if you are going to use it at all simply didn't exist. That changed about 20 years ago and it took a while for that to sink in to my consciousness. Once I realized that things had changed I also realized that feedback could finally be applied properly so that it would not cause harshness of its own. That was about 5 1/2-6 years ago, about the same time I realized that class D had to be taken seriously (and the time when we embarked on our class D project).
Nowadays you can buy inexpensive Chinese class D amps that sound better in many ways than the best SETs. Yes, I said that. I've had several customers comment to me about that. SETs and our OTLs are both solutions about what to do when feedback is shown to not work; the problem now is what do you do if feedback can now be applied properly?? Just put our collective heads in the sand as if nothing has happened in the last 20 years? As an amplifier manufacturer that would be foolish because the market will leave you behind. I imagine a lot of SET owners and manufacturers really won't like hearing this news and will be looking for ways to deny it. It likely does not feel good to know that a $100 class D amp can sound as smooth but with more detail than a $10,000 SET...
Look at it this way if you want: its not a measurement thing (even though most class D amps measure far better than most SETs), its a listening thing. IME class D amps vary in sound far more than tube amps do from the worst to the best. This means if you heard a class D amp you didn't like (and I think that's a fairly common experience) it says nothing at all about how good a class D amp can sound, just like if you heard a junky tube amp compared to a really nice one. I hope you don't think we haven't listened to this amp and done a fair bit of comparison
; one nice thing is that it showed us we were on the right track with our sonic goals with our OTLs all along.
I think roy is probably more determined then other reviewers to get the best out of components and rightfully so given all the effort most manufacturers have put into their products .
I guess reviewers come in all shapes and sizes , i reckon most do it beside their day job so a simple plug it in and listen approach is all they care for in the evening without to much fuzz .
John atkinson measures besides listening which is a different and much more elaborate process .
Audiophiles put far to much weight on reviewers opinions ( thats my " opinion " ) , reviewers are human beings with their preferences /tastes and flaws just like anybody else
I guess reviewers come in all shapes and sizes , i reckon most do it beside their day job so a simple plug it in and listen approach is all they care for in the evening without to much fuzz .
John atkinson measures besides listening which is a different and much more elaborate process .
Audiophiles put far to much weight on reviewers opinions ( thats my " opinion " ) , reviewers are human beings with their preferences /tastes and flaws just like anybody else
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?My observation is listeners are subjective in how they want to engage in listening. Designing an amp might be rocket science. Tuning an amp and speaker pairing to a room might also be science. But my "choice" on how I want the reviewer to set up a system comparison is subjective.
I have owned Altec 1570, CJ Premier 140, Rogue, Ampsandsound, Dartzeel, 845 SET, Allo class D and had Thrax Hybrid and Genesis amps at my home. Those amps all presented bass, mid and high frequency playback with a different character. Some dramatically different than others. I have my personal taste and like certain amps more than others.
I can not see how getting the most from any amp/speaker/room interaction might not necessitate the need to possibly move the speaker some amount to get the speaker room response as optimum as can be. I gravitate to people who recognize connecting a different component might influence the way it presents in a room and they take provisions to set it up as best as can be. The new piece might give the listener better insite into how the speaker is playing in the room. And if they hear the speaker could use adjustment, "I" want them to adjust it to get the most from the product. I want to know how the product sounds when at its best.
As I mentioned earlier, what are you placing the amp on. What about the power cord. The reviewer may have spent years optimizing their baseline system. And you think a fair comparison to a new component is to throw it into a room and system with no tuning and call it a day.
I don't believe getting a new component optimized is going to change the overall essence of how it performs and sounds. The inherent tone we hear will still come through. It just gives the new product the support it needs to shine at its highest potential. And that is exactly what I want the reviewer to do. Make it perform as best you possibly can. I am going to spend weeks, if not months doing the same in my listening space. I want to know what to expect. I don't really want a static A/B. It may leave the product hindered in its performance.
Thats my choice so I like the way Roy is going about performing a review.
I have owned Altec 1570, CJ Premier 140, Rogue, Ampsandsound, Dartzeel, 845 SET, Allo class D and had Thrax Hybrid and Genesis amps at my home. Those amps all presented bass, mid and high frequency playback with a different character. Some dramatically different than others. I have my personal taste and like certain amps more than others.
I can not see how getting the most from any amp/speaker/room interaction might not necessitate the need to possibly move the speaker some amount to get the speaker room response as optimum as can be. I gravitate to people who recognize connecting a different component might influence the way it presents in a room and they take provisions to set it up as best as can be. The new piece might give the listener better insite into how the speaker is playing in the room. And if they hear the speaker could use adjustment, "I" want them to adjust it to get the most from the product. I want to know how the product sounds when at its best.
As I mentioned earlier, what are you placing the amp on. What about the power cord. The reviewer may have spent years optimizing their baseline system. And you think a fair comparison to a new component is to throw it into a room and system with no tuning and call it a day.
I don't believe getting a new component optimized is going to change the overall essence of how it performs and sounds. The inherent tone we hear will still come through. It just gives the new product the support it needs to shine at its highest potential. And that is exactly what I want the reviewer to do. Make it perform as best you possibly can. I am going to spend weeks, if not months doing the same in my listening space. I want to know what to expect. I don't really want a static A/B. It may leave the product hindered in its performance.
Thats my choice so I like the way Roy is going about performing a review.
Spare me Ralph, I have heard the very best Class D (except yours of course?? I must not understand the question. Our MP-1 and one of our amps does have that 'transfer function'. Power amps must not have too much gain if they are not also higher power. Power amps by themselves don't have enough gain to work with a lot of sources (digital being the sometimes exception). So it sounds like you're asking why we don't make an integrated amp using our OTL approach and the answer is the product would be far too large and cumbersome. Plus- why would you when our class D can do the job and not sound appreciably different?
I have to imagine that you've not paid much attention to what I've previously written on this matter elsewhere. Our class D has a distortion signature very much like our OTLs and similar to SETs in that the 2nd and 3rd harmonics are the predominant distortion products- this because the non-linearities of the encoder scheme and the deadtime both impose lower ordered harmonics.
Early prototypes of our OTLs employed feedback. The original MA-2 had switchable feedback. So that goes back about 45-50 years. Not sudden- just sudden to your awareness of what I might be doing in spare time
The difference between the class D and our OTLs has been described by a number of people independently of each other but in a strikingly similar fashion- the difference being that the class D is slightly more transparent in the mids and highs but otherwise has the same relaxed character of the OTLs; the easiest difference is heard in the bass (and this is coming from OTL customers of ours...)- since the class D acts as a voltage source and the OTLs do not the bass difference is on that account. In most cases this means the bass is better too.
The reason this seems to be such an about face is because for most of my life the devices needed to really apply the kind of feedback needed if you are going to use it at all simply didn't exist. That changed about 20 years ago and it took a while for that to sink in to my consciousness. Once I realized that things had changed I also realized that feedback could finally be applied properly so that it would not cause harshness of its own. That was about 5 1/2-6 years ago, about the same time I realized that class D had to be taken seriously (and the time when we embarked on our class D project).
Nowadays you can buy inexpensive Chinese class D amps that sound better in many ways than the best SETs. Yes, I said that. I've had several customers comment to me about that. SETs and our OTLs are both solutions about what to do when feedback is shown to not work; the problem now is what do you do if feedback can now be applied properly?? Just put our collective heads in the sand as if nothing has happened in the last 20 years? As an amplifier manufacturer that would be foolish because the market will leave you behind. I imagine a lot of SET owners and manufacturers really won't like hearing this news and will be looking for ways to deny it. It likely does not feel good to know that a $100 class D amp can sound as smooth but with more detail than a $10,000 SET...
Look at it this way if you want: its not a measurement thing (even though most class D amps measure far better than most SETs), its a listening thing. IME class D amps vary in sound far more than tube amps do from the worst to the best. This means if you heard a class D amp you didn't like (and I think that's a fairly common experience) it says nothing at all about how good a class D amp can sound, just like if you heard a junky tube amp compared to a really nice one. I hope you don't think we haven't listened to this amp and done a fair bit of comparison
) and it sounds NOTHING like a good OTL…even yours. The distortion pattern is also nothing like it should be as the proportion of low and high orders is not right and there won’t be any effective masking or match with the ears own self-generated harmonics.Your claim about cheap Chinese class D is BS. A friend of mine bought several cheapies thinking he would find a cheap nirvana… they only caused headaches. Experiment over.
Rex, by making these changes to his setup, in an effort to “get the most out of the component” under evaluation, Mr. Gregory is doing a disservice to the reader. Mr. Gregory may very well be “optimizing” his system for the new component but by making inferences and wrongly attributing qualities to the component under review that are the result of very specific parameters and unique conditions to his system environment (speakers, room and associated equipment and set up particulars), he is misrepresenting what the reader can expect get from the component in their own system environment. This is the part that you and others who support Mr. Gregory’s flawed approach just cannot seem to grasp.
The most valuable information that reviewers can provide their readers is the relative comparison analysis between two or more “like/similar” components; and that is what A/B testing in a static reference system provides.
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Republicoftexas69
Well-Known Member
I am just thinking about digital - many modern digital sources can have outputs as high as 6V with minimal output impedance. And yes, I am just asking if you could change the design of the MA2 or M100 to sound the same of the MP1+MA2 or MP1+MA100? I have owned the first combo and preferred the sound with the preamplifier by far to the direct driving of the power amplifier.
I can imagine that your class D would also sound better with the MP1. Where can we find detailed information about your class D?
It is not by chance, accident, or coincidence, or for convenience, that other reviewers use A/B testing on a static reference system for their review process. Hence, it is the traditional review methodology for a reason. Makes you think why other reviewers haven’t used or adopted this “enlightened“ approach that Mr. Gregory is championing. Perhaps other reviewers have decided stay quiet and not comment on this out of professional courtesy.
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I think a question that needs to be addressed is, can the inherent sound and performance of a piece of equipment be changed by the use of accessories or moving speakers.
I personally am up in the air on this. I think the type of alterations needs to also be considered.
I don't think a footer or shelf will. It may bring more clarity or tighter bass. But I think the voicing of the component will come through.
I don't think speaker placement will either. Clarity and bass will change. I think moving a speaker from 1 room to another will make a radical change. Small moments in the same room won't.
Cables is tougher. When I was at Fremers, and other places, changing the electrical infrastructure can radically alter equipment performance. The first time I heard the Estelon speakers before the change at Fremers, Ed and I went to dinner and we both though mmheee. They were ok. After the change, I was stunned by the speaker and loved them.
I believe small changes to optimize the performance should be performes when reviewing gear.
In addition, reviews are not about A/B to something else. Its about the equilment under review. This idea nothing ahould change is not correct in my mind. If your going to review a piece of equipment, set it up as best as you can and share the type of shelf, footers, cables etc that the piece responsed best too.
Thats what I want to see in a review. An A/B is nice for comparison. But there is a whole lot more to a good review than noting how it sounds compared to some other brand I migh never have heard either.
I personally am up in the air on this. I think the type of alterations needs to also be considered.
I don't think a footer or shelf will. It may bring more clarity or tighter bass. But I think the voicing of the component will come through.
I don't think speaker placement will either. Clarity and bass will change. I think moving a speaker from 1 room to another will make a radical change. Small moments in the same room won't.
Cables is tougher. When I was at Fremers, and other places, changing the electrical infrastructure can radically alter equipment performance. The first time I heard the Estelon speakers before the change at Fremers, Ed and I went to dinner and we both though mmheee. They were ok. After the change, I was stunned by the speaker and loved them.
I believe small changes to optimize the performance should be performes when reviewing gear.
In addition, reviews are not about A/B to something else. Its about the equilment under review. This idea nothing ahould change is not correct in my mind. If your going to review a piece of equipment, set it up as best as you can and share the type of shelf, footers, cables etc that the piece responsed best too.
Thats what I want to see in a review. An A/B is nice for comparison. But there is a whole lot more to a good review than noting how it sounds compared to some other brand I migh never have heard either.
So how do you discern if the improvements derived from these “alterations” should be attributed to the “inherent sound and performance of a piece of equipment“ because they have allowed the component to be ”to optimize the performance” and “set it up as best as you can” versus the result of the changes that you made on other components in the systems, for example repositioning the speakers affecting the speaker/room interaction? Get the picture yet?
In your example of the changes in Fremer’s room you have answered the question above yourself, which is that you can’t.
How will you report and attribute these “changes to the system” in the review and attribute them for the benefit of the readers’ interested in what the component brings to the table and its inherent qualities? After all these are component reviews correct? And not reviewer’s system reviews.
Why is this so hard to understand?
You seem to be saying a reviewer as a human is incapable of sorting out a products performance if any change outside setting the new product into a place where something else sat and touching nothing else is the baseline. That is in essence saying humans are too simple in their overall capacities to comprehend and analyze much ouside a simple change. Maybe????
It is possible the reviewer may derive a more or less accurate opinion as based upon their past reference if to much is changed. This could definitely be the case with a wholesale change such as new electrical infrastructure, a new rack, a new TT. There very well may be a transition or time of acclimation to the new environment. But we dont live in a stagnant world. Reviewers hear things they like and buy them to keep as their reference. Maybe this is a good thing as they are constantly adjusting their base understanding. They might at times look back and realize something was better or worse than they thought at the time. Maybe its a human fallacy. But how do you escape that. We can't keep everything the same forever. That negates growth.
It is possible the reviewer may derive a more or less accurate opinion as based upon their past reference if to much is changed. This could definitely be the case with a wholesale change such as new electrical infrastructure, a new rack, a new TT. There very well may be a transition or time of acclimation to the new environment. But we dont live in a stagnant world. Reviewers hear things they like and buy them to keep as their reference. Maybe this is a good thing as they are constantly adjusting their base understanding. They might at times look back and realize something was better or worse than they thought at the time. Maybe its a human fallacy. But how do you escape that. We can't keep everything the same forever. That negates growth.
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