Re: Re: Amplifier burn-in
In an excellent design, it's possible to have the bias current be essentially fixed independent of temp, drift, power line voltage changes, etc. These amps will likely perform the same 5 seconds after power up as they will after running near clipping for many hours--at least with respect to bias current.
The whole burn-in thing just doesn't have any reasonable basis in fact. Any component variations that could take place over time are simply going to be much smaller than the normal tolerances between components AND much smaller than the ones that occur with temperature changes. So if people want to argue component changes are responsible for the dramatic pre and post burn-in differences they hear, then they should hear even greater differences at different temperatures and between two samples of the same product. They don't so either burn-in is due to some magical property none of us can point to, or as blind testing shows, it's just another form of psychological listening bias.
Where you can attribute the shift to something like bias current in an output stage, that has an easy answer. In most (decent) designs, the current should be reasonably consistent for a given temperature. So the designer/assembler can set the bias current to be correct at a given temp. That would explain why it ends up "right".janneman said:
In an excellent design, it's possible to have the bias current be essentially fixed independent of temp, drift, power line voltage changes, etc. These amps will likely perform the same 5 seconds after power up as they will after running near clipping for many hours--at least with respect to bias current.
The whole burn-in thing just doesn't have any reasonable basis in fact. Any component variations that could take place over time are simply going to be much smaller than the normal tolerances between components AND much smaller than the ones that occur with temperature changes. So if people want to argue component changes are responsible for the dramatic pre and post burn-in differences they hear, then they should hear even greater differences at different temperatures and between two samples of the same product. They don't so either burn-in is due to some magical property none of us can point to, or as blind testing shows, it's just another form of psychological listening bias.
Re: Re: Clarity
And still you do not open your eyes (ears🙂)..!?
I´m a little curious, what kind of speakers and in what kind of rooms have you done your blind testing?
/Peter
nw_avphile said:
And still you do not open your eyes (ears🙂)..!?
I´m a little curious, what kind of speakers and in what kind of rooms have you done your blind testing?
/Peter
An obvious alternative explanation to why a component sounds
better after "burn in" could be that after some time your hearing
has got used to the sound of the new component. An initial
harshness would then be an effect of the hearing not being
used to the somewhat different sound of this component.
When the hearing gets accustomed, the component will no
longer sound harsh, despite still sounding exactly the same
objectively. This theory would also explain why the change is
always to the better.
In my opinion there is nothing strange with this theory, since
the human hearing (physical ear and related parts of the brain)
is flexible and trainable.
better after "burn in" could be that after some time your hearing
has got used to the sound of the new component. An initial
harshness would then be an effect of the hearing not being
used to the somewhat different sound of this component.
When the hearing gets accustomed, the component will no
longer sound harsh, despite still sounding exactly the same
objectively. This theory would also explain why the change is
always to the better.
In my opinion there is nothing strange with this theory, since
the human hearing (physical ear and related parts of the brain)
is flexible and trainable.
The senses playing games....
Yes..that is also my opinion!!!
The same as when you turn on your air conditining set you ear the fan noise ...some hours later you don't notice any noise...but if you go out and retourn home some time later...you will ear the fan noise easily...😉
Yes..that is also my opinion!!!
The same as when you turn on your air conditining set you ear the fan noise ...some hours later you don't notice any noise...but if you go out and retourn home some time later...you will ear the fan noise easily...😉
Re: Re: Re: Clarity
The blind testing of the new versus burned-in components was done in our "high end" sound room. It was a great room with non-parallel walls, tube traps, sonex and other acoustical treatments. The speakers were Snell Type A series III ($6000/pair in the 80's). The interconnects where high-end Kimber. The turntable was an Oracle Delphi. I don't remember what arm was on it but it was a Grado Signature cartridge. The CD player was a California Audio labs which was regarded as one of the best around back then.
I'm sure Pan or someone will find fault with the circumstances of the test, or accuse all of us of being "deaf", etc. The fact is the high-end press then was writing of all these "dramatic" differences in how electronics sounded before and after burn-in. It was especially said that tube and digital gear required a lot of burn-in. So we took some of both and did a blind test and learned we couldn't hear any difference.
When you add the above experience to common sense and the total lack of any other kind of objective evidence supporting audible "burn-in", I think the conclusions are easy to make.
I also agree that human hearing does indeed change after sustained listening. I'm sure that accounts for some of what's attributed to "burn-in". That doesn't explain, however, people who fire up a new piece of gear. Listen for a few minutes and declare it "bad", lock it away playing Madonna for a week, and then listen again and find it sounding "good". What DOES explain this is the psychological expecation of better sound that the high-end press helped establish.
Pan, you've demonstrated yourself as a strong subjectivist. You've tried many times to discredit those who document factual information you do not agree with. I don't think anything I can post here is going to change your mind.Pan said:
The blind testing of the new versus burned-in components was done in our "high end" sound room. It was a great room with non-parallel walls, tube traps, sonex and other acoustical treatments. The speakers were Snell Type A series III ($6000/pair in the 80's). The interconnects where high-end Kimber. The turntable was an Oracle Delphi. I don't remember what arm was on it but it was a Grado Signature cartridge. The CD player was a California Audio labs which was regarded as one of the best around back then.
I'm sure Pan or someone will find fault with the circumstances of the test, or accuse all of us of being "deaf", etc. The fact is the high-end press then was writing of all these "dramatic" differences in how electronics sounded before and after burn-in. It was especially said that tube and digital gear required a lot of burn-in. So we took some of both and did a blind test and learned we couldn't hear any difference.
When you add the above experience to common sense and the total lack of any other kind of objective evidence supporting audible "burn-in", I think the conclusions are easy to make.
I also agree that human hearing does indeed change after sustained listening. I'm sure that accounts for some of what's attributed to "burn-in". That doesn't explain, however, people who fire up a new piece of gear. Listen for a few minutes and declare it "bad", lock it away playing Madonna for a week, and then listen again and find it sounding "good". What DOES explain this is the psychological expecation of better sound that the high-end press helped establish.
Precision
I don't disagree that these are demanding tasks, but they are VERY diferent ones to audio.
The input amp for a wide band spectrum analayser is rarely a challenge in the same way an audio amp is, it does not have to maintain the same levels of precision and linearity to both amplitude and phase simultaneously, over the same dynamic range and bandwidth.
I'm deeply familiar with RF analysers (I'm an RF engineer) - they are almost all swept devices, whose accuracy comes from stability and calibration factors, and the ability to change input attenuation to cope with the large dynamic ranges. The input amp cannot cope with the full dynamic range of the input signals, and in many cases is swept-tuned - it cannot display simultaneously two signals in real time - it uses persistance (in an analogue analyser) or digital storage to give the impression of real time operation.
Audio amps have to do everything over 10-12 octaves, and maybe 120-130dB simultaneously. RF analysers do not.
These arguments some because people assume audio to be less critical than it is, and fail to understand what they have to achieve.
None of the other examples you state have to maintain the same type of precision, to many domains simualtaneously.
Demanding Tasks - most certainly
Similar Tasks - not remotely.
and hence they are incomparable.
I don't disagree that these are demanding tasks, but they are VERY diferent ones to audio.
The input amp for a wide band spectrum analayser is rarely a challenge in the same way an audio amp is, it does not have to maintain the same levels of precision and linearity to both amplitude and phase simultaneously, over the same dynamic range and bandwidth.
I'm deeply familiar with RF analysers (I'm an RF engineer) - they are almost all swept devices, whose accuracy comes from stability and calibration factors, and the ability to change input attenuation to cope with the large dynamic ranges. The input amp cannot cope with the full dynamic range of the input signals, and in many cases is swept-tuned - it cannot display simultaneously two signals in real time - it uses persistance (in an analogue analyser) or digital storage to give the impression of real time operation.
Audio amps have to do everything over 10-12 octaves, and maybe 120-130dB simultaneously. RF analysers do not.
These arguments some because people assume audio to be less critical than it is, and fail to understand what they have to achieve.
None of the other examples you state have to maintain the same type of precision, to many domains simualtaneously.
Demanding Tasks - most certainly
Similar Tasks - not remotely.
and hence they are incomparable.
Christer said:
Reminds me of an experiment someone once demonstrated to me. With a good pair of headphones (or speakers and an amp) connected to a PC soundcard, play some familiar music in Winamp and drag one of the midrange EQ sliders down to -20dB. For arguments sake, try the 1kHz slider - that's in the presence region where our hearing is very sensitive. Listen to the music for a few minutes, and you get quite used to this drastically different new sound. More importantly, when you turn off the EQ, the music initially sounds different from the way it did originally. It seems your brain can adapt to different sounds remarkably easily.
I often think my HI-FI sounds better after I've been listening for a little while, regardless of how long the source components / amp have been powered up for.
See ya,
Tim.
trwh said:
Yes, the hearing has a tendency to adjust itself more easily when
using headphones than when listening through speakers. This
is exploited in the various sound theraphy methods, where the
goal is to adjust the hearing permanently. However, this also
means that your hearing can be damaged by listening to music
in headphones at loud volumes and/or with bad sound quality.
Headphones are also potentially more dangerous because you
only get air conduction of sounds, while when listening through
speakers, or to live music, you hear both via air conduction and
via bone conduction. This is important since the sound perceived
via bone conduction reaches the brain earlier and is also used
to control the ears protection mechanisms. The natural protection
against loud sounds does thus not work when using headphones.
Actually, the most elaborate of the sound theraphy methods
uses special headphones that has a third channel connected
to a device on the top of the head which transmits sound to
the cranium, thus giving also bone conduction.
Tim
This is a very common and well known function of the brain and is most easily seen in regards to vision. It is a well known fact that film and video cameras do not perform this adaptation, and thus the need to perform a white balance to get true colour rendition for video cameras, or use appropriate film stock or filters for film. So for instance the eye perceives flourescent and tungsten as white, as long as there are no external references, when they are actually green shifted and orange shifted respectively.
However this is something that can be overcome by training, as for instance in my job as a lighting designer I have to be able to spot the colour temperature/shift of a light source accurately, so as to treat it appropriately for the job in hand.
This is a very common and well known function of the brain and is most easily seen in regards to vision. It is a well known fact that film and video cameras do not perform this adaptation, and thus the need to perform a white balance to get true colour rendition for video cameras, or use appropriate film stock or filters for film. So for instance the eye perceives flourescent and tungsten as white, as long as there are no external references, when they are actually green shifted and orange shifted respectively.
However this is something that can be overcome by training, as for instance in my job as a lighting designer I have to be able to spot the colour temperature/shift of a light source accurately, so as to treat it appropriately for the job in hand.
Re: Precision
Take even a 500mhz ANALOG scope input amp. It has to be extremely flat from DC to a few hundred megahertz. It can be 3db down at 500mhz. No sweeping tricks here. That's a lot of octaves! It also has to manage that feat with signals of only a few millivolts and a low noise level (I realize they use input attenuators, but ultimately it has to have far more gain than an audio power amp does).
While audio requires flat response across a dozen octaves, big deal? An instrumenation amplifier must often be even flatter over a much wider range. In most designs, phase shift is related to frequency deviations. So if you get the first right, you get flat phase response as a bonus. No trick or extra precision there.
Dynamic range? Yes, audio equipment requires a good deal of that but so do lots of other applications. 130db for audio? Again, I point back to the GoldenEars. Much of the gear they think sounds best often has relatively poor dynamic range (< 90db). Given the range of human hearing it's hard to make a case for needing even 120db of dynamic range.
The left and right channels should ideally be matched within a fraction of a db or so. Again, this isn't difficult to do.
Let's talk about component precision as that's what your original posts addressed. There are only a few components in a typical power amp where precision really matters much. I mean if the input impedance drifts by 2%, what's that going to do to the sound? NOTHING. Ditto the output bias current. Ditto the diff pair current. Ditto the VAS current. Precision here just isn't much of an issue--especially in an amp with NFB. You can pretend it is if you like, but show us some objective proof?
Where precision comes close to making a difference in an audio amp is in the matching of the diff pair, and in the matching of the feedback/gain/pole components between the two channels. In this case, it's reasonable to say if the components leave the factory matched suitably close, they'll STAY THAT WAY. They will all be subjected to the same aging, the same temp changes, etc.
So absolute precison in an audio amp is really not a big deal as long as you match the diff pair and gain-related components of the two channels reasonably close.
Again, I refer folks to the Doug Self Blamless Amplifier. It has all the "precision" needed for excellent linearity, frequency response, phase reponse, low forms of distortion, etc., etc. The basic design is decades old and didn't take a rocket scientist to develop. It also will be indistinguishable in a blind listening test against any other amplifier with similarly low, or even lower, distortion and errors (subject to power issues as always).
Your original words were "if not THE, most demanding precision applications" so it didn't really qualify the type of task. I was referring to the amount of precision and design effort required for the engineering.ALW said:
Take even a 500mhz ANALOG scope input amp. It has to be extremely flat from DC to a few hundred megahertz. It can be 3db down at 500mhz. No sweeping tricks here. That's a lot of octaves! It also has to manage that feat with signals of only a few millivolts and a low noise level (I realize they use input attenuators, but ultimately it has to have far more gain than an audio power amp does).
While audio requires flat response across a dozen octaves, big deal? An instrumenation amplifier must often be even flatter over a much wider range. In most designs, phase shift is related to frequency deviations. So if you get the first right, you get flat phase response as a bonus. No trick or extra precision there.
Dynamic range? Yes, audio equipment requires a good deal of that but so do lots of other applications. 130db for audio? Again, I point back to the GoldenEars. Much of the gear they think sounds best often has relatively poor dynamic range (< 90db). Given the range of human hearing it's hard to make a case for needing even 120db of dynamic range.
The left and right channels should ideally be matched within a fraction of a db or so. Again, this isn't difficult to do.
Let's talk about component precision as that's what your original posts addressed. There are only a few components in a typical power amp where precision really matters much. I mean if the input impedance drifts by 2%, what's that going to do to the sound? NOTHING. Ditto the output bias current. Ditto the diff pair current. Ditto the VAS current. Precision here just isn't much of an issue--especially in an amp with NFB. You can pretend it is if you like, but show us some objective proof?
Where precision comes close to making a difference in an audio amp is in the matching of the diff pair, and in the matching of the feedback/gain/pole components between the two channels. In this case, it's reasonable to say if the components leave the factory matched suitably close, they'll STAY THAT WAY. They will all be subjected to the same aging, the same temp changes, etc.
So absolute precison in an audio amp is really not a big deal as long as you match the diff pair and gain-related components of the two channels reasonably close.
Again, I refer folks to the Doug Self Blamless Amplifier. It has all the "precision" needed for excellent linearity, frequency response, phase reponse, low forms of distortion, etc., etc. The basic design is decades old and didn't take a rocket scientist to develop. It also will be indistinguishable in a blind listening test against any other amplifier with similarly low, or even lower, distortion and errors (subject to power issues as always).
nw_avphile
nw_avphile,
I wish that you (and some of the other guys at the board) had a chance (and the interest 🙂) to visit a MODERN high end room to evaluate different components.
No matter if we talk about "warm up" "burn in" or simply the difference between products you need GOOD stuff to get meaningful results.
Thoose Snells may have been expensive but SOTA.. nope.
As I mentioned earlier I heard no difference at all between cables with my Sonus Faber´s, but after a couple of years and new speakers all those differences I have been writing about is EASY to hear.
This is a promise, with good gear (and decent ears) you will hear difference between cables, LOW distortion amps and CDP´s/SACD`s. You will hear the difference between clocks in a digital source.
Burn in I´m sure is sometimes in "the head" as all other dramatic differences people reports about, BUT there is no doubt that in some cases this is real.
If you want to know what a MODERN high end rig is capable of, try to visit someone with Kharma, Avalon or Lumen White top of the line speakers, and I assure you that most of the things you say is impossible will be real... even for you.
Differences can be heard on lesser systems, but for a clear result I recommend a speaker with Seas Excel drivers or Accutons, simply because this is drivers with resolving capacity way above the soft drivers from the 80´s-early 90´s.
My opinions are based on facts and experience, many others opinions are based on beliefs and phsycologigal bias. Those of you that stay in the game long enough will understand what I (and "the other guy´s") talk about, but only if you open your ears and minds and do it on a SOTA (or close to) rig.. 🙂
Happy listening!
/Peter
nw_avphile,
I wish that you (and some of the other guys at the board) had a chance (and the interest 🙂) to visit a MODERN high end room to evaluate different components.
No matter if we talk about "warm up" "burn in" or simply the difference between products you need GOOD stuff to get meaningful results.
Thoose Snells may have been expensive but SOTA.. nope.
As I mentioned earlier I heard no difference at all between cables with my Sonus Faber´s, but after a couple of years and new speakers all those differences I have been writing about is EASY to hear.
This is a promise, with good gear (and decent ears) you will hear difference between cables, LOW distortion amps and CDP´s/SACD`s. You will hear the difference between clocks in a digital source.
Burn in I´m sure is sometimes in "the head" as all other dramatic differences people reports about, BUT there is no doubt that in some cases this is real.
If you want to know what a MODERN high end rig is capable of, try to visit someone with Kharma, Avalon or Lumen White top of the line speakers, and I assure you that most of the things you say is impossible will be real... even for you.
Differences can be heard on lesser systems, but for a clear result I recommend a speaker with Seas Excel drivers or Accutons, simply because this is drivers with resolving capacity way above the soft drivers from the 80´s-early 90´s.
My opinions are based on facts and experience, many others opinions are based on beliefs and phsycologigal bias. Those of you that stay in the game long enough will understand what I (and "the other guy´s") talk about, but only if you open your ears and minds and do it on a SOTA (or close to) rig.. 🙂
Happy listening!
/Peter
[offtopic]
Christer, thanks for your post - very interesting considering my hearing damage. I wrote more about it here: http://www.diyvideo.com/forums/showthread.php?s=&postid=85685#post85685
Al, interesting to hear about your learned response in lighting design. I suppose it would be possible to learn to override your auditory sensory adaptation as well.
Tim.
[/offtopic]
Christer, thanks for your post - very interesting considering my hearing damage. I wrote more about it here: http://www.diyvideo.com/forums/showthread.php?s=&postid=85685#post85685
Al, interesting to hear about your learned response in lighting design. I suppose it would be possible to learn to override your auditory sensory adaptation as well.
Tim.
[/offtopic]
Re: nw_avphile
As for hearing modern high-end, I've heard plenty of it. As I mentioned earlier in this thread, I was just at CES in January where tens of millions of dollars of high-end audio are featured in hundreds of suites at the Alexis Park hotel. You go from suite to suite, close the door, sit down in the sweet spot, and listen to ultra high-end systems often set up by the designer who's standing behind you. Some of these systems sound great.
We also have a few excellent high-end dealers here where I live that carry stuff like Levinson, etc. I visit them regularly as well. So I'm familiar with the state of the high-end art.
I wish I could come visit you and stand behind your equipment rack and make changes (or not) and have you identify things without knowing what you're listening to. This is something you clearly HAVE NOT experienced in the proper way.
Some things (especially speakers) make a difference. I think a good SACD sounds better than the same CD. A good CD player sounds better than an old cheap one. But many things, like high quality amplifiers, speaker wires, interconnects and new versus burned-in components DO NOT make an audible difference in the sound once you remove the psychological bias. NOBODY HERE HAS PRESENTED ANY OBJECTIVE EVIDENCE TO THE CONTRARY. PERIOD. Instead, there is A LOT of objective evidence supporting the other side. But you choose to ignore all that or somehow believe a lot of very well educated people are wrong and publishing false information (or however you rationalize it in your mind).
Like I said, you've demonstrated that no matter what I or anyone else posts here or elsewhere, you're going to believe what you want to believe. That's fine. Close your eyes, drink your wine, listen to your music, and stop reading this discussion. It obviously upsets you.
I think i need to do the same thing.
State of the art has nothing to do with this discussion Pan. As I see it, it was just as valid to test the claims of audiophiles in the 80's and is today. If burn-in was thought to exist but didn't then, what's changed to make it exist now? It was myth then, and it's still myth.Pan said:
As for hearing modern high-end, I've heard plenty of it. As I mentioned earlier in this thread, I was just at CES in January where tens of millions of dollars of high-end audio are featured in hundreds of suites at the Alexis Park hotel. You go from suite to suite, close the door, sit down in the sweet spot, and listen to ultra high-end systems often set up by the designer who's standing behind you. Some of these systems sound great.
We also have a few excellent high-end dealers here where I live that carry stuff like Levinson, etc. I visit them regularly as well. So I'm familiar with the state of the high-end art.
I wish I could come visit you and stand behind your equipment rack and make changes (or not) and have you identify things without knowing what you're listening to. This is something you clearly HAVE NOT experienced in the proper way.
Some things (especially speakers) make a difference. I think a good SACD sounds better than the same CD. A good CD player sounds better than an old cheap one. But many things, like high quality amplifiers, speaker wires, interconnects and new versus burned-in components DO NOT make an audible difference in the sound once you remove the psychological bias. NOBODY HERE HAS PRESENTED ANY OBJECTIVE EVIDENCE TO THE CONTRARY. PERIOD. Instead, there is A LOT of objective evidence supporting the other side. But you choose to ignore all that or somehow believe a lot of very well educated people are wrong and publishing false information (or however you rationalize it in your mind).
Like I said, you've demonstrated that no matter what I or anyone else posts here or elsewhere, you're going to believe what you want to believe. That's fine. Close your eyes, drink your wine, listen to your music, and stop reading this discussion. It obviously upsets you.
I think i need to do the same thing.
trwh said:
Ah yes, I remember that thread now. Actually, sound theraphy
is reported by many to have a positive effect on tinnitus. I am
not sure I should bring that up here in this thread, but if you
would like to know more, feel free to mail me. I have done
sound theraphy myself, but mainly for other reasons, so I do
have some knowledge about it.
For those who are interested, the visual adaption to varying light
conditions is referred to as the whiteness principle (well, I am
not sure about the correct english term). The mechanism is that
we always use the brightest spot we can see as reference and
then "declare" this spot to be white, whatever colour it actually
has, and then adapt the interpretation of the whole spectrum
as necessary. Hence, if two light sources had identical spectra
but are shifted so they have their average at different
wavelengths, it should not be possible to tell these light sources
apart . However, since different light sources will differ not only
in average wavelength but also in the shape of their spectra,
the relation between colours is not accurately preserved in most
cases, which gives us a clue to what the light source might be.
In particular, most artificial light sources will have a rather poor
preservation of colour relations, with the exception of so called
daylight fluoroscent tubes, which are used whenever accurate
colour reproduction is important.
I see now
I see now why we are not relating to each others viewpoint - speakers may make the most audible difference to sounds, but make the least difference to the music that comes out of a system.
I think we listen to different things.
Andy.
I see now why we are not relating to each others viewpoint - speakers may make the most audible difference to sounds, but make the least difference to the music that comes out of a system.
I think we listen to different things.
Andy.
Time to put my thoughts on this subject down properly I think...
Whilst I agree in principal that amps that are well designed to produce an accurate "wire with gain" should sound alike, I suspect everyone here is missing a major psychological and subjective factor - the designer of the amp in question.
This bias is intrinsic to the question of wether amps sound alike and can be differentiated by any means, be it DBT or subjective.
Personally I belive that the subjective nature of the designer will tune the response of the amp to suit their own preferences, and after a period of time this leads to a house sound for a particular manufacturer, and this will change only gradually, as the designer or design team change.
For instance, in subjective testing, I have always been able to tell different manufacturers, such as Arcam and Musical Fidelity apart, simply because of the house sound their products have, not to mention Naim, who took this to extremes, by producing very fast, rythmical and accurate, but not very listenable amps.
This difference is even more extreme when it comes to amps from different geographical regions, it is very easy to tell amps from the Far East, or the USA, from UK made amps, simply because of the different tastes of the designers. This is partly I suspect down to the differing listening situations, for instance big empty rooms in the USA, medium sized rooms full of clutter in Europe, and small, sparse rooms in the Far East.
As Hi-Fi, is, above all, a subjective experience, and the measurement regime we have, I think all would agree, is lacking, we can only rely on our ears and mind. Personal perception is flawed, it is very easy to trick the mind into believing anything, if you don't believe me, just go see a really good close-up magician or mentalist.
Despite the carping of some cynics here, DBT is a valid method if carried out with the correct controls, and indeed, if all amps were made identical, would prove it beyond all doubt, but I fear, all amps are not identical, because of the preferences of the designers.
But this doesn't mean that DBT has no use in diy, in fact if it is used in the upgrade process, I think it is very valid, even if it only allows you to tune your kit to suit your ears, without the pressure of fashion or other influences. And before anyone comes back with the idea that Hi-Fi only reproduces the truth, it does not, it only reproduces the collective biases of those that recorded and produced it- there is no such thing as a perfect recording.
BTW, I am completely open to this theorising all being completely wrong if I were to experience it in a properly set up DBT.
Food for thought I hope?😉
Whilst I agree in principal that amps that are well designed to produce an accurate "wire with gain" should sound alike, I suspect everyone here is missing a major psychological and subjective factor - the designer of the amp in question.
This bias is intrinsic to the question of wether amps sound alike and can be differentiated by any means, be it DBT or subjective.
Personally I belive that the subjective nature of the designer will tune the response of the amp to suit their own preferences, and after a period of time this leads to a house sound for a particular manufacturer, and this will change only gradually, as the designer or design team change.
For instance, in subjective testing, I have always been able to tell different manufacturers, such as Arcam and Musical Fidelity apart, simply because of the house sound their products have, not to mention Naim, who took this to extremes, by producing very fast, rythmical and accurate, but not very listenable amps.
This difference is even more extreme when it comes to amps from different geographical regions, it is very easy to tell amps from the Far East, or the USA, from UK made amps, simply because of the different tastes of the designers. This is partly I suspect down to the differing listening situations, for instance big empty rooms in the USA, medium sized rooms full of clutter in Europe, and small, sparse rooms in the Far East.
As Hi-Fi, is, above all, a subjective experience, and the measurement regime we have, I think all would agree, is lacking, we can only rely on our ears and mind. Personal perception is flawed, it is very easy to trick the mind into believing anything, if you don't believe me, just go see a really good close-up magician or mentalist.
Despite the carping of some cynics here, DBT is a valid method if carried out with the correct controls, and indeed, if all amps were made identical, would prove it beyond all doubt, but I fear, all amps are not identical, because of the preferences of the designers.
But this doesn't mean that DBT has no use in diy, in fact if it is used in the upgrade process, I think it is very valid, even if it only allows you to tune your kit to suit your ears, without the pressure of fashion or other influences. And before anyone comes back with the idea that Hi-Fi only reproduces the truth, it does not, it only reproduces the collective biases of those that recorded and produced it- there is no such thing as a perfect recording.
BTW, I am completely open to this theorising all being completely wrong if I were to experience it in a properly set up DBT.
Food for thought I hope?😉
Re: I see now
Andy. Very well put. I have never before seen this point made so succinctly 🙂
dave
ALW said:
Andy. Very well put. I have never before seen this point made so succinctly 🙂
dave
Re: Re: Re: Re: Re: Re: ...to continue pan,
...😀...is this guy capable of not missing the point??😀
Pan said:
...😀...is this guy capable of not missing the point??😀
Re: PSRR
..AAAHHHH...at last!!!.... some folks here are able to present and analyse facts and data dispassionately and intelligently........there is hope after all....🙂
jcarr said:
SY said:
..AAAHHHH...at last!!!.... some folks here are able to present and analyse facts and data dispassionately and intelligently........there is hope after all....🙂
Re: The Amplifier Expert
...interestingly most detractors of D. Self's work seem to content themselves with inane and entirely vacous remarks like'Self doesn't listen to what he calculates'....or '...Self doesn't listen to what he designs'...or some such wholly silly juvenile dross..........no energy is expended, and indeed no interest is expressed in rebuting his findings on a case by case basis....🙁
...seriously.....does anyone know of an amp. designer who doesn't at any time listen to program through his designs?🙄
nw_avphile said:
...interestingly most detractors of D. Self's work seem to content themselves with inane and entirely vacous remarks like'Self doesn't listen to what he calculates'....or '...Self doesn't listen to what he designs'...or some such wholly silly juvenile dross..........no energy is expended, and indeed no interest is expressed in rebuting his findings on a case by case basis....🙁
...seriously.....does anyone know of an amp. designer who doesn't at any time listen to program through his designs?🙄
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