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In Reply to: That would call for you to have a sense of humor. posted by Dan Banquer on December 19, 2005 at 18:40:28:
our "lacking in mental acuity" poster andy who obviously disagrees with you.For what it's worth, I think that I would much rather have a pair of LNP-150s than the Alesis. I was hoping you might explain the reasons why for andy's sake.
After all, I spent $2000 twenty five years ago for one of Nelson Pass' amps and nearly $10000 for a pair of Luke Manleys. You're actually preaching to the choir. How about to the unwashed masses?
rw
Follow Ups:
"After all, I spent $2000 twenty five years ago for one of Nelson Pass' amps and nearly $10000 for a pair of Luke Manleys."So, what do you want us to do? Genuflect at the alter of E-Status-Symbol because he has the cash to drop on high priced amps. Or would you like to hear me sing to you the Scarecrow's song (do di do di do di do do..If I Only Had A Brain.....)? @$$#0!&
his 75 watt / channel amps cost $3300? Perhaps he might answer you. When I took andy's position and pointed out that one could spend a tenth of that amount on a pro amp, his response was:I have given technical explanations on many occaisons (sic). Since you don't have the mental acuity to absorb it I feel no need to reiterate what I said in the past since it will be lost due to your lack of education.
Defensiveness aside, he seems to think there are compelling reasons for his (and other's) products to be more expensive than low end pro amps.
I agree.
As for the Wizard of Oz, Dan will be playing the part of the cowardly lion.
rw
> our "lacking in mental acuity" poster andy who obviously disagrees with you.Why do you think I disagree with anything that Dan has said?
> For what it's worth, I think that I would much rather have a pair of LNP-150s than the Alesis. I was hoping you might explain the reasons why for andy's sake.
For my sake? I think I have good grasp of what Dan would say and can look it up if I wish. Personally, I am far more interested in your reasoning.
> After all, I spent $2000 twenty five years ago for one of Nelson Pass' amps and nearly $10000 for a pair of Luke Manleys. You're actually preaching to the choir. How about to the unwashed masses?
Why do you think this choice of amplifiers aligns you with Dan's views? Or is the only point that you are making that you have spent lots of money on amplifiers?
Why do you think I disagree with anything that Dan has said?Let's review your rigorous criteria for state of the art musical reproduction:
"To date, my experience, the experience of those I know and the experience and actions of audio professionals indicates that properly designed modern amplifiers operating well away from clipping and driving a benign load are not audibly distinguishable."
That criteria can be met for a song. Do you really think that other than musician and engineer, Dan is a crook who wanted to fleece the public with a product that cost then times that of other amps with no inherent value?
Personally, I am far more interested in your reasoning.
I'll let Dan speak for his own design.
Why do you think this choice of amplifiers aligns you with Dan's views?
Because of the dozens of designers who listen to their products and realize that such a simplistic view of amplifier performance as yours is insufficient. If low end junk could sound as good as better designs, people would buy it. If a car manufacturer could duplicate the performance of a Z06 Corvette for $6000, they would sell quite a few.
rw
> Do you really think that other than musician and engineer, Dan is a crook who wanted to fleece the public with a product that cost then times that of other amps with no inherent value?I suggest we let others read the thread to see who said what.
> > Personally, I am far more interested in your reasoning.
> I'll let Dan speak for his own design.That is a pity because your reasoning is of interest.
> Because of the dozens of designers who listen to their products and realize that such a simplistic view of amplifier performance as yours is insufficient.
In your view, are these designers looking for fidelity or something else in their designs?
> If low end junk could sound as good as better designs, people would buy it.
I am not wholly sure what you meant to say here? The market for high end audio is very small and has shrunk quite a lot since the 90s. The market for cheap audio on the other hand is large and, I would guess, reasonably stable.
I suggest we let others read the thread to see who said what.Or view their actions. Would you buy a 75 watt /channel amp for $3300?
That is a pity because your reasoning is of interest.
Since he declined to answer, I'll be happy to offer my viewpoints. First of all, I have not heard his amps so I really have no point of comparison. Generally speaking, I trust musically inclined engineers over number crunchers. Like Nelson Pass. Like John Curl. Like Luke Manley. Like Jud Barber. Like William Z. Johnson. Like Lew Johnson. Like Lee Kuby. I'll stop here for brevity. All of these guys use listening tests in the final analysis.
In your view, are these designers looking for fidelity or something else in their designs?
That's an interesting question because there is no single set of criteria. It all depends upon your perspective. If you use metrics such as THD and favor high NFB designs, then the answer would be certainly not. None of these guys chase the largely irrelevant white rabbit. Yes, these designers do seek musical fidelity in ways that continue to defy numerical analysis. Or audio cowboy quick comparisons.
I am not wholly sure what you meant to say here?
While materialistic audiophile gearheads who buy solely on price and perceived status do exist, the high end market (with far more companies today than ever before) continue to produce products whose audible performance is not duplicated for significantly less.
rw
> Would you buy a 75 watt /channel amp for $3300?At the beginning of last year it looked like I might have to because of a difficult load but the requirement did not materialise in the end.
> Generally speaking, I trust musically inclined engineers over number crunchers. Like Nelson Pass. Like John Curl. Like Luke Manley. Like Jud Barber. Like William Z. Johnson. Like Lew Johnson. Like Lee Kuby. I'll stop here for brevity. All of these guys use listening tests in the final analysis.
Thanks for the answer.
> > In your view, are these designers looking for fidelity or something else in their designs?
> That's an interesting question because there is no single set of criteria.Would you not consider fidelity to be a single well defined criteria?
> Yes, these designers do seek musical fidelity in ways that continue to defy numerical analysis.
I am not sure what you mean by musical fidelity given that fidelity is defined by linearity in an amplifier. Assuming you mean musical without the fidelity, but please correct me if you do not, as typfied by a valve amplifiers for example, what leads you to conclude this departure from linearity cannot be analysed numerically?
> Or audio cowboy quick comparisons.
I do not understand.
Andy, we do not deliberately add distortion to any amp. Sometimes we find that some distortion (usually lower order harmonic (2nd or 3rd) in small quantities, does not significantly effect the sound quality, so we will make some engineering tradeoffs, such as lower or no global negative feedback, with a tendency for greater measured distortion, but subjectively improved listening performance.
It is an important trade-off, BUT we do not allow distortion on purpose.
What many people do not know or understand is that almost all audio tube amps have inherently LOW negative feedback. This is because the necessary coupling capacitors and output transformer limit the feedback factor to approximately 20dB, due to low frequency instability, or 'motorboating' problems.
When we reduce the amount of negative feedback in transistor amplifiers to this amount, we find that the sound quality improves, IF the actual circuit is linear enough (open loop) to behave at least as well as a tube amp. Why this is so, is complex. It can be TIM, inherently higher open loop bandwidth (reduction of input stage FM distortion), and lowering the generation of higher order harmonics from lower harmonics through the feedback process.
Whatever, we find that lower feedback generally sounds better, all else being equal.
Making virtually zero distortion (for all practical purposes) is relatively easy. Just try to measure any decent IC op amp!
It is a constant struggle to make better sounding products, since we have to make them intrinsically more linear without feedback, operate them in a class A mode, and still have decent, if not ridiculous 'specs' for the marketing department or for THX approval.
> Sometimes we find that some distortion (usually lower order harmonic (2nd or 3rd) in small quantities, does not significantly effect the sound quality,Agreed if the level is small enough.
> so we will make some engineering tradeoffs, such as lower or no global negative feedback, with a tendency for greater measured distortion, but subjectively improved listening performance.
If the level of distortion has risen to audibly significant levels why do you not equate the difference you hear with the difference you measure?
> When we reduce the amount of negative feedback in transistor amplifiers to this amount, we find that the sound quality improves, IF the actual circuit is linear enough (open loop) to behave at least as well as a tube amp. Why this is so, is complex.
I am tempted to say try me but I am off for my holidays at the crack of dawn and will not see a computer for a few weeks.
> It can be TIM, inherently higher open loop bandwidth (reduction of input stage FM distortion), and lowering the generation of higher order harmonics from lower harmonics through the feedback process.
Why cann't measurement tell you what it is? The whole process of not equating predictions and measurements with what is heard is baffling to me as an engineer. How do you reason about what to do?
> Whatever, we find that lower feedback generally sounds better, all else being equal.
All else cannot be equal or they would surely sound the same.
> Making virtually zero distortion (for all practical purposes) is relatively easy. Just try to measure any decent IC op amp!
It is bit harder and more costly with larger currents but I would agree that low enough distortion can be achieved.
> It is a constant struggle to make better sounding products, since we have to make them intrinsically more linear without feedback,
Why without feedback?
I can understand the argument this is what the customer will pay for (which is, of course, why customers used to get very low THD amplifiers) and I can understand because it sounds good. What I am querying is the linearity part.
> operate them in a class A mode,
Why?
> and still have decent, if not ridiculous 'specs' for the marketing department
Why? I thought customers in the market for valve amplifiers took little or no notice of measured distortion. Or do you sell solid state amplifiers as well/instead?
> or for THX approval.
I understand this one.
Andy, your questions are naive. We have been working of this stuff for more than 35 years. I.e., why global negative feedback seems to make amps sound lousy, especially if more than 20dB.
I will give you real references that point to the problems, and perhaps, the solutions, if you are really interested, but I can't just tell you in a few sentences what the problems are, and how to work around them.
Your Class A vs Class AB question shows your lack of understanding of distortion generation in ANY audio component, even at the theoretical level. Perhaps, you should take some classes in analog engineering design.
> Andy, your questions are naive.My simple questions were asking you to expand on statements you had made that seemed unreasonable to me.
> We have been working of this stuff for more than 35 years. I.e., why global negative feedback seems to make amps sound lousy, especially if more than 20dB.
In which case I find it hard to understand why you did not give a more convincing initial response.
> I will give you real references that point to the problems, and perhaps, the solutions, if you are really interested, but I can't just tell you in a few sentences what the problems are, and how to work around them.
Thanks. I have an interest and would prefer references. Not so much the problems of high global feedback but the sounds lousy aspect.
> Your Class A vs Class AB question shows your lack of understanding of distortion generation in ANY audio component, even at the theoretical level.
I asked why class A? I fail to see why this means I do not have a reasonable grasp of the pros and cons even at a theoretical level.
> Perhaps, you should take some classes in analog engineering design.
The problem here is the sounds lousy. People teaching such classes will discuss things like gain, forms of distortion and the pros and cons of various approaches but they will all assume the objective is linearity and not some deviation from it that sounds attractive.
"Would you not consider fidelity to be a single well defined criteria?"Sorry, I would just like to comment on this statement. Fidelity to an oscilloscope is not the same as fidelity to a human listener. Types and levels of distortion that look to be of no consequence on a computer screen can have profound effect on the listener. So the question of fidelity is not as easy to assess as you propose.
I hope you will agree that exact reproduction of the source material would be an ideal definition for fidelity; however, the question that arises is this, if a piece of gear measures nearly perfect and yet still doesn't sound right (subjectively speaking) then why is that small residual imperfection playing such an important role in the sound that is reproduced? Why is another piece of gear measureably further from an exact replication of the source material subjectively much closer?
If it is impossible to make a truly distortion free amplifier, then isn't it smarter to put that distortion in the blind spot of human awareness rather than make it really small but sitting right in the open where even very tiny levels are obvious? Kind of how Sony uses noise shaping in SACD, not to eliminate the problems but to push them where they are outside human perception. Amplifier design for the last 4 decades (until recently) was obssessed with pushing it down as low as possible, and they did push it low, but invariably pushing it where it was the most obvious. The result was often poor sound quality. Poorer measuring but better sounding amps tend to have their problems more in the human blind spots.
This brings up a further question: Who are the engineers designing high fidelity gear for, the test bench or human listeners? When designers make a real effort to apply what has been learned to date about psychoacoustics to electronics design then we might begin to see a directed progress in sound quality rather than the hit or miss results we see now. The sound of gear would also likely begin to converge (as it should if fidelity to the recording and to how humans hear is the goal.).
> "Would you not consider fidelity to be a single well defined criteria?"
> Sorry, I would just like to comment on this statement.Do not apologise. So long as you are not an "objectivist" your answer will be of interest to me.
> Types and levels of distortion that look to be of no consequence on a computer screen can have profound effect on the listener.
Why do you believe this to be true?
> So the question of fidelity is not as easy to assess as you propose.
30 years ago fidelity was not an ambiguous term in home audio nor is it to an engineer today. It is interesting that its meaning might have shifted in home audio circles today.
> I hope you will agree that exact reproduction of the source material would be an ideal definition for fidelity;
It is the definition of fidelity to many including myself.
> however, the question that arises is this, if a piece of gear measures nearly perfect and yet still doesn't sound right (subjectively speaking)
How do you determine sounds right?
(I can see how to determine sounds different.)
> then why is that small residual imperfection playing such an important role in the sound that is reproduced?
As far as I am aware, all experiments have shown that significant levels of distortion need to be present to be audible. Your statement is counter to my knowledge, do you have references?
> Why is another piece of gear measureably further from an exact replication of the source material subjectively much closer?
Again we are back to this closer business. I can accept sounds more pleasant but not closer unless I can see a valid way to determine it.
> If it is impossible to make a truly distortion free amplifier, then isn't it smarter to put that distortion in the blind spot of human awareness rather than make it really small but sitting right in the open where even very tiny levels are obvious?
This would be the case if we could not make good enough amplifiers but we can, given a few caveats, and for a reasonable price.
> Amplifier design for the last 4 decades (until recently) was obssessed with pushing it down as low as possible, and they did push it low, but invariably pushing it where it was the most obvious.
As far as I am aware, there has been little development of traditional class AB designs for a couple decades since it became demonstrably good enough to do the job albeit at a fairly high cost in efficiency and materials. Getting that cost down and efficiency up would seem to be the major force behind the design of amplifiers in recent years. (This is audio rather than just high end audio.) Is this not your impression?
> The result was often poor sound quality. Poorer measuring but better sounding amps tend to have their problems more in the human blind spots.
Are you sure you are not confusing this with having nice sounding problems?
> This brings up a further question: Who are the engineers designing high fidelity gear for, the test bench or human listeners?
Neither, they are designing them to be sold. This means giving the customer what they want. It also means finding someway to distinguish your products in a postive way in the customers eyes which is why marketing is so vital in this case.
> When designers make a real effort to apply what has been learned to date about psychoacoustics to electronics design then we might begin to see a directed progress in sound quality rather than the hit or miss results we see now.
Hmmm. What do you think the market is for a modestly priced linear amplifier with a niceness control which adds valve sound?
> The sound of gear would also likely begin to converge (as it should if fidelity to the recording and to how humans hear is the goal.).
My understanding is that as far as amplifiers are concerned this happened a few decades ago when people stopped being able to distinguish well designed amplifiers (subject to caveats) in audibility tests. Do you consider these results to be invalid?
How do you explain the fact that large numbers of people prefer the sound from valve amplifiers? Is this because the valve amplifiers have a higher level of fidelity or that they sound nicer or perhaps both?
Lower order distortion products are easier for listeners to integrate into the intended listening experience, partly because they have analogues, if you will, with real world phenomena that hearing mechanisms have evolved to deal with.When you start dealing with higher order distortion products (both harmonic and intermodulation) produced by an amplifier, especially with feedback, there are no longer ear/brain processing mechanisms available to integrate them, they tend to be more prominent where hearing acuity is greatest, and they are increasingly associated with a multiplicity of spectral components both in the original signal, and produced yet are still strongly correlated with the source signal, thus are drastically more detectable as various forms of sonic degradation.
High levels of feedback invite momentary internal signal overloads as the feedback attempts to correct particularly when the signal is not strongly band limited and especially when out of band noise is introduced such as with RF, clock noise with DSP, power supplies, Class D amps, noise products from AC line, etc. In a well controlled test environment, these factors are of course reduced or eliminated, so high feedback gets a bit of a free pass on the test bench.
See my other post about transistor amplifiers' problems with the 'first watt'.
nt
At the beginning of last year it looked like I might have to because of a difficult load but the requirement did not materialise in the end.Ah, I didn't realize that you were from the UK! I have thoroughly enjoyed my two trips to Scotland where my family hails from long ago.
Is it fair then to say that in the absence of special load driving requirements, your experience is there are no audible improvements to be found in more expensive amps than some that are quite modestly priced?
Would you not consider fidelity to be a single well defined criteria?
Definitely not.
I am not sure what you mean by musical fidelity given that fidelity is defined by linearity in an amplifier.
Which would you rather have - 1% pure second harmonic distortion or 0.1% seventh harmonic distortion?
While the former seems less linear, my experience suggests that such would be far more faithful to a musical event than much smaller errors of a highly offensive nature. I'd rather hike 10 miles with a rock in my pocket than to have a pebble in my shoe.
By "audio cowboy quick comparisons", I mean instantaneous ABX switching. That works well for gross frequency differences, but not necessarily well for detecting spatial or other subtle differences. I prefer extended listening.
rw
> Is it fair then to say that in the absence of special load driving requirements, your experience is there are no audible improvements to be found in more expensive amps than some that are quite modestly priced?Not when phrased like that. Firstly the amplifiers have to be designed to be linear and implemented well enough to achieve it over some of their operating range when presented with the load of the desired speaker and the current required to achieve the desired listening levels. More expensive amplifiers (designed to be linear) generally maintain linearity over a wider operating range and can drive more demanding loads than their cheaper equivalents. If the demands on the cheaper amplifier are not sufficient to provoke audible nonlinearity then it will sound the same as the more expensive amplifier (designed to be linear). This is by definition if both amplifiers achieve linearity to within audible perception.
At the expensive end this rules out almost all valve amplifiers and probably some of the expensive but odd solid state designs (I have no experience with the latter and the reviews of them I have seen are not informative so it is a guess) because they are not sufficiently linear nor, to be fair, are they intended to be if they are to have that valve sound.
At the cheap end, it tends to rule out amplifiers that cannot maintain linearity when driving real loudspeakers at realistic SPLs. This is a significant function of the loudspeaker the amplifier is required to drive and so "audibly nonlinear" is not an independent property of the amplifier. The price point where a significant proportion of amplifiers are good enough has been falling over the years. Exactly where the limits are today for a given type of loudspeaker load is something you would expect the home audio press to report if it acted in the interests of the consumers.
> > Would you not consider fidelity to be a single well defined criteria?
> Definitely not.That is a surprising. Is this because the word fidelity does not mean to you simply a linear amplifier?
Is the sole task of an amplifier to linearly increase the input signal? Or should it aim to do more such as sound musical?
Much perceived musical amplifier quality resides in the 'first watt' which is barely characterized in standard measurement protocols. This is where high levels of feedback provides a bandaid to partially cover up the low level linearity problems of amplifiers that operate near Class B using very high transconductance output devices (e.g. transistors).
Firstly the amplifiers have to be designed to be linear and implemented well enough to achieve it over some of their operating range when presented with the load of the desired speaker and the current required to achieve the desired listening levels.Indeed. My tube amps meet those criterion quite well. Better in fact than an older, but very good SS amp I have.
At the cheap end, it tends to rule out amplifiers that cannot maintain linearity when driving real loudspeakers at realistic SPLs.
What are "realistic SPLs" to you? For me, that averages in the 70s and 80s with occasional peaks in the 90s. I am totally unconcerned as to how many PA bins my amp can drive. Here again, most amplifiers today meet your very basic requirements.
I can see, however, where that would be important to those professionals who work with auditorium or rock music sound reinforcement systems, often to ear bleeding levels.
Is this because the word fidelity does not mean to you simply a linear amplifier?
I already answered that question. Perhaps you might answer the question I posed to you in response. If you've forgotten, here it is again.
Which would you rather have - 1% pure second harmonic distortion or 0.1% seventh harmonic distortion?
Understanding that concept as morricab has more eloquently described goes to the heart of my answer.
Is the sole task of an amplifier to linearly increase the input signal? Or should it aim to do more such as sound musical?
Naturally. In the real world, however, there are only errors. Some errors are far more egregious than others. Musically consonant distortion (even at higher levels) is more musical than dissonant forms. Like cars? Take two samples with equal lateral cornering capability as measured on a skid pad. Would you prefer the one with a neutral handling state or one that exhibits snap oversteer? There are qualitative measures to performance that your simple approach ignores.
rw
> Indeed. My tube amps meet those criterion quite well. Better in fact than an older, but very good SS amp I have.What is the basis for this observation?
> What are "realistic SPLs" to you?
What ever level the person wants. Some amplifiers are linear at low outputs but not at normal listening levels. This was the point of my comment.
> > Is this because the word fidelity does not mean to you simply a linear amplifier?
> I already answered that question.Yes but the answer was surprising and so I sought the reason behind it.
> Perhaps you might answer the question I posed to you in response. If you've forgotten, here it is again.
> Which would you rather have - 1% pure second harmonic distortion or 0.1% seventh harmonic distortion?It isn't a question that can be answered without more context particularly what one is trying to achieve with the distortion.
> Understanding that concept as morricab has more eloquently described goes to the heart of my answer.
I am reasonably aware of the both levels of audible distortion and the role harmonics play in musical instruments.
> Naturally. In the real world, however, there are only errors. Some errors are far more egregious than others. Musically consonant distortion (even at higher levels) is more musical than dissonant forms.
So, in summary, is your view that all amplifiers produce audible distortion? but the better amplifiers produce less intrusive forms even though the measured distortion levels may be higher?
Andy, you appear to just ask questions. What is the point of this?
> Andy, you appear to just ask questions.I hope I also answer all the ones I am asked that are answerable and/or not intended to offend.
> What is the point of this?
This is a fairly standard method of seeking information from someone with a viewpoint that differs from yours. Working away asking questions and giving answers until the basis for the difference is revealed. Yours is an odd question and I am not sure I have answered the question you intended?
Questions are easy. Real answers are difficult. Please study the subject further.
> Questions are easy. Real answers are difficult. Please study the subject further.Again we would seem to disagree. If someone has a different viewpoint then by definition one does not know why. Asking the right questions to draw out this information is far from easy in many cases and particularly if there is a risk of triggering an emotional response. However, if someone is asked a question they know the answer to then giving the answer is nearly always easy. Of course, this may not be the case if they do not quite know the answer or are trying to bluff.
...I mentioned to you previously that John Curl is one of the most knowledgeable, talented and respected analogue audio designers in the past 30 years.That you disagree with him, fail to understand much of the conversation and ask simplistic questions says more about you than him.
Exactly what IS your background and what are you trying to get at here?
Do you actually believe the only way to listen to an audio component to determine its musicality is in a controlled lab setting or a DBT?
Perhaps that would explain your failure to grasp the idea of two components sounding more or less faithful to the "sound of music" regardless of their bench measurements.
Not sure this will be read after the break and the thread dropping off the bottom of the page but here is the response anyway.> Is English your first language?
I have answered this before and assume the question to be rhetorical.
> That you disagree with him,
I asked questions about his statements. This is not necessarily disagreement but simply a means to clarify the information provided and/or gain more.
> fail to understand much of the conversation
I am not aware of failing to understand the information stated. What I did not understand was the reasoning and, to a degree, the form of the response hence the questions.
> and ask simplistic questions
Questioning is surely the normal way to gather and exchange information in forums such as this? And when there is doubt surely simple questions are to be preferred to complicated ones which are likely to include incorrect assumptions?
> says more about you than him.
Not sure I would agree with the more but the questions asked and, particularly, the questions evaded certainly provide information.
> Exactly what IS your background
I am an engineer and scientist currently working in the field of acoustics/audio.
> and what are you trying to get at here?
My main interest in the forum is how audio enthusiasts such as yourself can vehemently hold and maintain erroneous and fairly easily checkable views about audio equipment.
In the case of John he responded to one of my postings with statements to which I, in turn, responded.
> Do you actually believe the only way to listen to an audio component to determine its musicality is in a controlled lab setting or a DBT?
This is a nonsensical question for a number of reasons. Firstly, without defining precisely what musicality is nobody can design an experiment to measure it. Secondly, the objective of audio reproduction for many is to accurately reproduce the source and not to add musicality whatever that may be.
responsible for creating our recordings have this same "what do you mean by distortion spectra" lack of pertinent knowledge.rw
Thanks Mike. I sometimes wonder who (or why) am trying to 'help', if I can, to understand the nature of high quality audio design.
Personally, I would also like to really understand how a Strad. violin sounds as good as it does, in most cases. Sure, I have heard theories and explanations, but I think it is still a mystery.
...its supreme musicality had nothing whatsoever to do with bench measurements or DBT testing.
What is the basis for this observation?Observation! My speakers reach satisfactory levels with 700 watts.
It isn't a question that can be answered without more context particularly what one is trying to achieve with the distortion.
Faithfulness to the musical event devoid of audible artifacts resembling the sound of fingernails scraping a chaulkboard.
So, in summary, is your view that all amplifiers produce audible distortion?
I've never met a perfect one yet. Have you? The question is a matter of degrees.
...but the better amplifiers produce less intrusive forms even though the measured distortion levels may be higher?
Yes. Current models of Crown amplifiers, for example, have higher measured rates of distortion vs. their models from the 70s. After laying a few eggs, their engineers now get it for the most part.
rw
> What is the basis for this observation?
Observation! <Some wise fellow on another board once referred to himself not as a subjectivist but as an observationalist, as opposed to a "non-experiential theorist". This wise fellow used your same moniker. :)
There is no such thing as a linear amplifier only varying degrees of non-linearity and more importantly where does that non-linearity lie with regard to human perception. An oscilloscope or FFT only points out to you that the distortion is there and what type it is but it does not give you the correlation of that distortion to what it sounds like."are they intended to be if they are to have that valve sound.
"with all due respect, you don't have a clue what you are talking about. Do you have ANY extended experience with this kind of amplification or are you talking only "from the specs"? THese amp designers are not trying to make tone controls you know but trying to design with the human being at the focus of the effort. Thr result is often something audibly superior in spite of "mediocre" bench performance.
What do you know about human perception and psychoacoustics? I suggest you do a little reading on the matter because it is not as cut and dry as looking at THD on a meter.
Start by reading the master's thesis of Daniel Cheever (type his name in google you will find it).
> with all due respect, you don't have a clue what you are talking about.You do not believe typical valve amplifiers have a characteristic sound?
> Do you have ANY extended experience with this kind of amplification or are you talking only "from the specs"?
I am not sure what you mean by extended experience. I obviously have not used valve amplifiers for many decades but have a familiarity with their sound from that time and the very occasional hearing since. I do not seek out the specifications of valve amplifiers because they hold no interest (if this is what from the specs means).
> What do you know about human perception and psychoacoustics?
A reasonable amount since it is a subject I was taught a long time ago and is a small part of my job now. However, it is a part I seek to avoid rather than pursue and so I am by no means an authority.
> Start by reading the master's thesis of Daniel Cheever (type his name in google you will find it).
This was posted earlier by someone and I looked at it then. You would consider this to be a reference of some authority that makes a valid case for valve amplification based on human perception and psychoacoustics?
" I obviously have not used valve amplifiers for many decades "Jesus! How can you claim memory of sounds from decades ago? Many of the amps from that time are considered sub par by the best tube designs today. This is not a valid reference from which to discuss these things.
"I do not seek out the specifications of valve amplifiers because they hold no interest (if this is what from the specs means)."
I don't want you to seek out specs on those amps I want you to seek out the amps and while you are at tube preamps and good hybrid amps. Go listen to them and get some experience with the latest creations. I can tell you that some should blow you away and others will leave you feeling slimed in honey or chocolate. What you won't likely find is an amp that leaves you cold and feels sterile like a hospital or clean room. Then go hear some of the latest creations from Krell or better yet Halcro to hear what multibuck SS sounds like. They won't sound the same either but they will likely sound less musical to you.
I don't think Cheever is THE authority but his approach is scientifically valid and makes a good case for using psychoacoustic properties in the design of amplifiers.
I agree.
Perhaps a little too much honesty? An admission like that (tubes more musical) from you (of all people) may lead me to going tubes all the way!!!! Currently used tube pre but SS power. Surely convienence isn't the *only* reason for going SS?:)
p.s. I expect the answer has something to do with the bucks it would require to get the same level of bass performance, using tubes, out of my power hungry full range speakers. I used to use a good 60watt per channel (SS) but the sound was 'woosie' and 'wabbley' (sorry, that's the impression I got). Had to go with 150watt of vintage SS bliss to appreciate first foray (at home) into full range sound. Love it, can't see myself switching to mini-monitors again!
...mixing tubes and solid state to get the best of each. Many times, they will complement each other.> Currently used tube pre but SS power.>
As long as the two you have work well together, and the amp is a good match with your speakers, it would be hard to improve without spending a lot more money, IMO.
that you have no interest in soliciting from Banquer the source of the "Pro" DBT tests that demonstrate differences in amplifiers.Not interested in challenging you beliefs I see.
(Mind you, have to admit that Banquer's rollover play dead antics might have calmed whatever wind of curiosity that may have been swirling around your sails, but still it's a shame you don't have the motivation to check it out. After all I've noticed you have an ample supply of hot air ... use it effectively.)
I will not advertise my stuff here. There is plenty of info on my web site, not that it really matters anymore, and some very interesting reviews from people like Dave Moulton and Glen O'Hara. If people want to read the info on my web site they are welcome to do so. They can also contact me privately if they have any questions.
d.b.
I gather that as a musician, you find basic designs like Dynaco ST-120s, etc. lacking in their ability to naturally reproduce music as well as the best.Did you focus on reducing odd order harmonics? Was it high bandwidth? Was it solely due to monoblock construction? Discrete device matching? Some notion of how you chose to use / not use negative feedback? Cascade vs. cascode operation? Transition from class A bias point? Power supply stiffness? What did your listening tests reveal that the numbers did not?
I find your apparent duality perplexing: on the one hand, you carry the banner high of "all good amps sound basically the same" according to the professionals especially when there's some other EE listening. Yet your own product which no doubt took significant effort on your part to develop and refine clearly doesn't fit that simplistic model.
rw
"I find your apparent duality perplexing: on the one hand, you carry the banner high of "all good amps sound basically the same" according to the professionals especially when there's some other EE listening. Yet your own product which no doubt took significant effort on your part to develop and refine clearly doesn't fit that simplistic model."You have misinterpreted me from day one. I'm a registered independent in the political wars that you and others are fond of persuing. If you want to read more try the FAQ section of my website. I really suspect you won't, and really only desire to persue your own political agenda since you have no concept of analog electronics, and nor do you really care to learn. I have come to the conclusion that people like you, bjh, morricab, and kuller are just dysfunctional people trying to impose their dysfunctions on everyone else while they pose as "knowledgeable" people. Have you thought about getting help? I'm sure there are many good mental health professionals in your area.
d.b.
"dysfunctional people trying to impose their dysfunctions on everyone else while they pose as "knowledgeable" people"Gee Dan last time I checked, you were not qualified to discuss the psychiatric state of asylum inmates. Therefore, you are an idiot for claiming knowledge outside your professed field of expertise. This is your logic anyway and how you approach those in this asylum. It never occurred to you that scientists that are experts in one field, could with study, become experts in other fields as well? Time to wake up Dan. The circuit you are using isn't even your own invention so why act so high and mighty?
-Attention to eliminating high order distortion spectra
-Use shielded cable for internal wiring
-Attention to RFI/EMI issues
-Moderate DFFor some reason, you prefer to exert added effort complaining.
rw
some more amusing pet tricks. We've already seen you "roll over play dead", what other ones do you know.
Speaking of stupid pet tricks, didn't I see you on Letterman the other night?
Oh come on Dan, can't you do better than that, Like "your mother wears combat boots". HA!Yeah, come on Dan, you are getting out of the business so spill the beans about what makes your amp better than many others (in your opinion)? I remember you going on once about grounding issues that you resolved that supposedly made a big difference. What else? The rest sounded pretty straight forward: Class AB bipolar, complementary with high negative feedback if I am not mistaken. All the operating points tied down really tight, right? Regulated? Unregulated? You can share an awful lot, Dan, without giving away how it is exactly designed. No one is asking you for a schematic (even the guy from darTZeel is not afraid of that and he asks $20K for his amp).
This is a technical forum, remember and inquiring minds want to know technical information about how YOU design amps. I know other designers who have no problems sharing their design ideas with me (two who make very expensive stuff using very clever circuits...I have learned much from them) and why they think it makes their design better than most. Why do you use more than 30db of feedback? To lower THD? To lower output impedance? To keep it from oscillating? Why do you use bipolar transistors in a Class AB configuration and not tubes or mosfets? Here is your chance to show real technical prowess and you are simply telling us to piss off. Don't assume that we are too stupid to understand what you have designed, many of us are not.
You have already proven that not only are near totally ignorant, but incapable of rudimentary understanding. I am not going to even attempt to teach you anything becasue you refuse to study the fundamentals.
d.b.
was Banquer's response to andy19191's "in cahoots" standard spiel, only the spiel in this case was personalized just for Banquer's case, paraphrasing ... "Banquer is not openly corrupt, he just symbiotically and self-interestedly talking the talk, walking the walk".Banquer's response is *hands down* the *most pathetic* display I have ever seen here, in fact ... anywhere!
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