Re: Good amplifiers
I agree with some of what you say. But once you reduce the input/output difference to the level of most any well designed amplifier, it becomes relatively easy to argue the amplifier distortions are NO LONGER AUDIBLE. The blind tests support this argument. Amplifiers that can be distinguished in a blind test tend to do poorly on the null test, those that cannot be distinguished, do well.
I suggested folks who can produce a known attenuation in their system play music at a comfortable level (a level you would use to listen for subtle differences in a piece of audio gear). Then reduce the music by say 60 or 70db and see how loud the result is. You may find you can no longer hear it from your listening position! If you can hear it, it's so incredibly faint, it's easily masked by even the slightest background noise, let alone the original signal.
So again, it stretches common sense and credibility for someone to claim they can hear something that's 60 or 70db below the signal--or at least they can hear it well enough for it to account for the vast differences people profess to hear between amplifiers.
The thing to keep in mind here is the things I'm suggested can be verified with a minimum of special equipment. This stuff isn't philosophical, hypothetical or intangible. It's real and verifiable. Conversely, those who disagree, are asking others to make a leap of faith and simply believe in what cannot be objectively verified.
That's what the null test is for! It tells you both subjectively (if you listen to it) and objectively (if you measure it) EXACTLY how the amplifier is changing, adding to, taking away from, distorting or otherwise altering the input signal.ashok said:
I agree with some of what you say. But once you reduce the input/output difference to the level of most any well designed amplifier, it becomes relatively easy to argue the amplifier distortions are NO LONGER AUDIBLE. The blind tests support this argument. Amplifiers that can be distinguished in a blind test tend to do poorly on the null test, those that cannot be distinguished, do well.
I suggested folks who can produce a known attenuation in their system play music at a comfortable level (a level you would use to listen for subtle differences in a piece of audio gear). Then reduce the music by say 60 or 70db and see how loud the result is. You may find you can no longer hear it from your listening position! If you can hear it, it's so incredibly faint, it's easily masked by even the slightest background noise, let alone the original signal.
So again, it stretches common sense and credibility for someone to claim they can hear something that's 60 or 70db below the signal--or at least they can hear it well enough for it to account for the vast differences people profess to hear between amplifiers.
The thing to keep in mind here is the things I'm suggested can be verified with a minimum of special equipment. This stuff isn't philosophical, hypothetical or intangible. It's real and verifiable. Conversely, those who disagree, are asking others to make a leap of faith and simply believe in what cannot be objectively verified.
Re: Science takes a stand!
This whole thread reminds me very much of a Bose thread. Although it didn't provide any valid conclusion it was very entertaining. The person who started the current thread seems to be very enthusistic about his point of view, yet to me it seems like we are talking here about apples and oranges. If I can use a good analogy I could compare it to a discussion between two types of people. One type have never had sex and they just talk about it using their imagination and try to describe it the best way they feel approporiate. Second type, had sex and they know what it's all about. There is no way they can pass their experience and sensations they were subjected to, to the group of the people who never had it.
Who really cares about that kind of a challenge and what does it really prove?
Even if I wouldn't be able to hear the difference between both amps in a DBT, it won't suddenly make me able to enjoy the sound of a $300 integrated amp
nw_avphile said:
This whole thread reminds me very much of a Bose thread. Although it didn't provide any valid conclusion it was very entertaining. The person who started the current thread seems to be very enthusistic about his point of view, yet to me it seems like we are talking here about apples and oranges. If I can use a good analogy I could compare it to a discussion between two types of people. One type have never had sex and they just talk about it using their imagination and try to describe it the best way they feel approporiate. Second type, had sex and they know what it's all about. There is no way they can pass their experience and sensations they were subjected to, to the group of the people who never had it.
nw_avphile said:
Who really cares about that kind of a challenge and what does it really prove?
Even if I wouldn't be able to hear the difference between both amps in a DBT, it won't suddenly make me able to enjoy the sound of a $300 integrated amp
There is another side to the whole subject. Some of you may be right claiming that properly measuring and capable with a load amps should sound the same and you can actually predict their sound by conducting so called null test. I can accept that and I can see your point.
Yet for me such equipment is useless, since it's not design to create real music. It's like a copy machine, which will never create nice picture but only passes out what it's fed.
For me a good amp is like a good violin. I don't care if it's 100% accurate if the price I'm paying for that is lifeless product, the music which doesn't have body and soul. For me the amplifier has to create "flesh and blood" experience, it has to provide a lot of technicolor and drama (I'm not using my words here, but I like them). Only then I can really enjoy the amp. Otherwise, what is keeping me from listening to a basic system that came with my computer?
Yet for me such equipment is useless, since it's not design to create real music. It's like a copy machine, which will never create nice picture but only passes out what it's fed.
For me a good amp is like a good violin. I don't care if it's 100% accurate if the price I'm paying for that is lifeless product, the music which doesn't have body and soul. For me the amplifier has to create "flesh and blood" experience, it has to provide a lot of technicolor and drama (I'm not using my words here, but I like them). Only then I can really enjoy the amp. Otherwise, what is keeping me from listening to a basic system that came with my computer?
Re: Re: Science takes a stand!
I designed and built a high-end dual mono, fully symmetrical power amp. It has regulated higher voltage rails for the gain and driver stages, hand matched parts, audiophile WonderCaps, Roederstein metal film resistors, dual huge torroids, soft recovery rectifiers, fancy gold connectors, multiple current mirrors, Kimber Kable, silver solder, etc, etc. It's a great amp, was a labor of love, and it's still going strong. But I also built it before I discovered the reality of blind testing. So please don't insinuate I'm a DIY or audiophile virgin.
Well... as I've explained more than once, I've done the high-end audio thing and was on the other side of the fence for quite a while. I still consider myself an audiophile and have spent five figures on my "hobby" so it's not like I'm sitting at home with an Emerson stereo from Wal-Mart.Peter Daniel said:
I designed and built a high-end dual mono, fully symmetrical power amp. It has regulated higher voltage rails for the gain and driver stages, hand matched parts, audiophile WonderCaps, Roederstein metal film resistors, dual huge torroids, soft recovery rectifiers, fancy gold connectors, multiple current mirrors, Kimber Kable, silver solder, etc, etc. It's a great amp, was a labor of love, and it's still going strong. But I also built it before I discovered the reality of blind testing. So please don't insinuate I'm a DIY or audiophile virgin.
Re: Re: Re: Science takes a stand!
Even if you went to the other side of a fence it either wasn't long enough or you picked the wrong spot. If, as you say, you spend five figures on your hobby, you wouldn't be mentioning the above parts. This is the basic stuff and not high end. Just as an example, I'm using $28 resistors in my amps and $75 caps, and I still didn't justify to spend 2 grands for the interconnects. And I don't even dream about considering myself as a hard core audiophile yet.
nw_avphile said:
Even if you went to the other side of a fence it either wasn't long enough or you picked the wrong spot. If, as you say, you spend five figures on your hobby, you wouldn't be mentioning the above parts. This is the basic stuff and not high end. Just as an example, I'm using $28 resistors in my amps and $75 caps, and I still didn't justify to spend 2 grands for the interconnects. And I don't even dream about considering myself as a hard core audiophile yet.
Re: THE GOOD, THE BAD AND THE UGLY.
Likewise, measuring the difference between the input and output of an amplifier and finding if it's at a level that's way below audibility is also objective.
I don't care what components you start with to do your comparisons. If you you can tell them apart in a proper blind test, then you have my vote there's an audible difference between them. Pick the one you like better and go from there.
But if you can't tell them apart, I argue they really don't have any significant audible difference (to the people listening at least).
Yes they are, but not being able to tell the difference between a $300 Japanese piece of mainstream consumer electronics and audiophile gear costing more than ten times as much isn't subjective at all. It's black and white. Either you can hear enough of a difference to do better than you would just guessing, or you can't.fdegrove said:
Likewise, measuring the difference between the input and output of an amplifier and finding if it's at a level that's way below audibility is also objective.
I don't care what components you start with to do your comparisons. If you you can tell them apart in a proper blind test, then you have my vote there's an audible difference between them. Pick the one you like better and go from there.
But if you can't tell them apart, I argue they really don't have any significant audible difference (to the people listening at least).
B&W.
Hi,
Like it or not the difference is still there.
I am not blind, I don't listen blind either and to me the entire issue is moot in that I notice time and time again that even across the globe and independently from eachother people notice the same:
In casu: people like Fred Dieckmann, Peter Daniel, Eric (Mr.FeedacK), countless others worldwide and myself are in concordance about quite a few, yet seemingly, unmeasured/uncorrelated phenomena.
It is sometimes freaky, spooky, to see someone across the globe confirm your own experiments...and that is exactly how I hope the net will accellerate development in audio.
Other than that null us out if you like, we know better than that.
Cheers,
/Frankie Pedantie.
Hi,
Like it or not the difference is still there.
I am not blind, I don't listen blind either and to me the entire issue is moot in that I notice time and time again that even across the globe and independently from eachother people notice the same:
In casu: people like Fred Dieckmann, Peter Daniel, Eric (Mr.FeedacK), countless others worldwide and myself are in concordance about quite a few, yet seemingly, unmeasured/uncorrelated phenomena.
It is sometimes freaky, spooky, to see someone across the globe confirm your own experiments...and that is exactly how I hope the net will accellerate development in audio.
Other than that null us out if you like, we know better than that.
Cheers,
/Frankie Pedantie.
Re: DOUBLE BLIND DOUBLE DEAF?
The previous thread was about polarity and how it is not synonymous with phase. Apparently you still seem to be laboring under the notion that phase and polarity are synonymous.
This discussion is about phase, as it has to do with time delays.
<i>High-Frequency Phase Response Specifications--Useful or Misleading? Jensen, Deane, JAES, Vol. 36, Issue 12, p. 968, preprint no. 2398.</i>
I'm simply distinguishing between frequency-dependent delays and frequency-independent delays.
It's phase when it's phase and it's polarity when it's polarity. Absolute polarity and absolute phase are not one and the same. Though since you can't seem to distinguish the difference between polarity and phase, I can understand your confusion.
Yes. And as long as frequency versus phase is a linear function, group delay, which is the first derivative of this function, will be flat and all frequencies will be delayed by the same amount. And the shape of the waveform will not be altered.
It's not simply a matter of the order of the filter. Two second order filters with the same cutoff frequency may have vastly different group delays.
Take a look at the group delay of a second order Bessel compared to say a second order Chebychev.
Well, techincally speaking, you would want that. A flatter (i.e. better) group delay that is. The flatter the group delay, the more linear the system.
And it's group delay that shows you how frequency dependent the delays are.
You're missing the point.
The point is, simply looking at phase data doesn't impart any useful information.
Here, let me give you an example from the preprint I cited above.
<center>
<img src="http://www.q-audio.com/images/phase1.jpg">
</center>
This is a phase plot of two networks, A and B.
Considering just the phase data, one might conclude that network B was worse than network A. However network B actually has a much flatter group delay plot. Meaning that network B is the more linear of the two and alters the signal the least.
So again, forget about phase. What matters is group delay.
se
fdegrove said:
The previous thread was about polarity and how it is not synonymous with phase. Apparently you still seem to be laboring under the notion that phase and polarity are synonymous.
This discussion is about phase, as it has to do with time delays.
<i>High-Frequency Phase Response Specifications--Useful or Misleading? Jensen, Deane, JAES, Vol. 36, Issue 12, p. 968, preprint no. 2398.</i>
I'm simply distinguishing between frequency-dependent delays and frequency-independent delays.
It's phase when it's phase and it's polarity when it's polarity. Absolute polarity and absolute phase are not one and the same. Though since you can't seem to distinguish the difference between polarity and phase, I can understand your confusion.
Yes. And as long as frequency versus phase is a linear function, group delay, which is the first derivative of this function, will be flat and all frequencies will be delayed by the same amount. And the shape of the waveform will not be altered.
It's not simply a matter of the order of the filter. Two second order filters with the same cutoff frequency may have vastly different group delays.
Take a look at the group delay of a second order Bessel compared to say a second order Chebychev.
Well, techincally speaking, you would want that. A flatter (i.e. better) group delay that is. The flatter the group delay, the more linear the system.
And it's group delay that shows you how frequency dependent the delays are.
You're missing the point.
The point is, simply looking at phase data doesn't impart any useful information.
Here, let me give you an example from the preprint I cited above.
<center>
<img src="http://www.q-audio.com/images/phase1.jpg">
</center>
This is a phase plot of two networks, A and B.
Considering just the phase data, one might conclude that network B was worse than network A. However network B actually has a much flatter group delay plot. Meaning that network B is the more linear of the two and alters the signal the least.
So again, forget about phase. What matters is group delay.
se
Nameing thing correctly
I've no objection to an amplifier that is deliberately designed to be non-linear. However, I think that in the interest of honesty in commerce and respect for the customer it should clearly be called an "amplifiing signal processor" or something equivalent. Then it can be sold by in the time honored manner of touting the features and benefits. Nothing wrong with that.
I've no objection to an amplifier that is deliberately designed to be non-linear. However, I think that in the interest of honesty in commerce and respect for the customer it should clearly be called an "amplifiing signal processor" or something equivalent. Then it can be sold by in the time honored manner of touting the features and benefits. Nothing wrong with that.
I knew I'd scanned in the plot of group delay for the networks I posted the phase plots of (I did this a year or so ago) but I couldn't find the file at the time. I did some more digging and finally found them. So here is the accompanying group delay plots to go with the phase plots.
<center>
<img src="http://www.q-audio.com/images/delay1.jpg">
</center>
se
<center>
<img src="http://www.q-audio.com/images/delay1.jpg">
</center>
se
Re: Re: Re: Re: Science takes a stand!
As for $28 resistors and you not being hard core yet, I guess I'd hate to see how much a real hard core DIY guy spends on resistors?
To bring yet another argument into this fold--especially for those of you who consider $8 capacitors in the signal chain to be a joke--I ask you to consider what most of the audio you listen to has gone through before it ever made it into your listening room. Yeah, there are a tiny handful of unusual audiophile recordings made on tweak equipment, but they won't even fill a small shelf--even if you did like all the obscure artists. 99.5% of what most of us listen to was recorded with regular old studio gear like the stuff made by Mackie.
Mainstream studio gear is full of garden variety ten cent capacitors, one penny resistors, fifty cent op-amps, twenty cent regulators, cheap copper wire, etc. There are the mic pre-amps, mixers, EQs, filters, noise gates, processors, effects loops, recording amps (for analog recordings), the ADCs (for digital recording), etc. The signal in the average recording has passed through dozens of cheap op-amps--many running as buffers with 100db or more of dreaded negative feedback.
All that studio gear isn't connected together with teflon insulated grain-aligned silver alloy cables with $100 connectors machined out of unobtanium. Nope, just regular old interconnects that probably even have some oxygen in their copper.
Taken as a whole from instrument to your speakers, the audio signal has spent the majority of its life in very non-audiophile electronics. The playback part of the electronics chain is actually the much smaller piece of the big picture.
Members contributing to this thread have suggested systems are only as strong as their weakest link. They've laughed at audiophile capacitors that cost only $8--let alone ones that cost a few cents. They've suggested that something as small as having unused equipment plugged into the same 120 volt circuit can "mask" the results of blind testing.
I ask those same people, how much "masking" occurs from all those cheap capacitors, op-amps, resistors, interconnects, connectors, un-powered equipment, and other "sins" that have already been "inflicted" onto 99.5% of the music we listen to?
Or put another way: If all that clearly non-audiophile studio gear doesn't offend our ears when we listen to music, why should a few more pieces of similar gear in our own systems offend our ears? How can one more cheap capacitor or op-amp make a difference when the signal has already been through dozens of them?
Well this amp was built in the early 90's, and at that time, the components I used where some of the best available then. The "high-end" wasn't quite so obscene back then. The parts I used were some of the same ones the reviewers of the day were raving about in $20,000 commercial products.Peter Daniel said:If, as you say, you spend five figures on your hobby, you wouldn't be mentioning the above parts. This is the basic stuff and not high end. Just as an example, I'm using $28 resistors in my amps and $75 caps... And I don't even dream about considering myself as a hard core audiophile yet.
As for $28 resistors and you not being hard core yet, I guess I'd hate to see how much a real hard core DIY guy spends on resistors?
To bring yet another argument into this fold--especially for those of you who consider $8 capacitors in the signal chain to be a joke--I ask you to consider what most of the audio you listen to has gone through before it ever made it into your listening room. Yeah, there are a tiny handful of unusual audiophile recordings made on tweak equipment, but they won't even fill a small shelf--even if you did like all the obscure artists. 99.5% of what most of us listen to was recorded with regular old studio gear like the stuff made by Mackie.
Mainstream studio gear is full of garden variety ten cent capacitors, one penny resistors, fifty cent op-amps, twenty cent regulators, cheap copper wire, etc. There are the mic pre-amps, mixers, EQs, filters, noise gates, processors, effects loops, recording amps (for analog recordings), the ADCs (for digital recording), etc. The signal in the average recording has passed through dozens of cheap op-amps--many running as buffers with 100db or more of dreaded negative feedback.
All that studio gear isn't connected together with teflon insulated grain-aligned silver alloy cables with $100 connectors machined out of unobtanium. Nope, just regular old interconnects that probably even have some oxygen in their copper.
Taken as a whole from instrument to your speakers, the audio signal has spent the majority of its life in very non-audiophile electronics. The playback part of the electronics chain is actually the much smaller piece of the big picture.
Members contributing to this thread have suggested systems are only as strong as their weakest link. They've laughed at audiophile capacitors that cost only $8--let alone ones that cost a few cents. They've suggested that something as small as having unused equipment plugged into the same 120 volt circuit can "mask" the results of blind testing.
I ask those same people, how much "masking" occurs from all those cheap capacitors, op-amps, resistors, interconnects, connectors, un-powered equipment, and other "sins" that have already been "inflicted" onto 99.5% of the music we listen to?
Or put another way: If all that clearly non-audiophile studio gear doesn't offend our ears when we listen to music, why should a few more pieces of similar gear in our own systems offend our ears? How can one more cheap capacitor or op-amp make a difference when the signal has already been through dozens of them?
"I used were some of the same ones the reviewers of the day were raving about in $20,000 commercial products."
Reviewer's opinions and cost of components.......
This seems to be just the type of questionable influences I mentioned in my post.
"I designed and built a high-end dual mono, fully symmetrical power amp. It has regulated higher voltage rails for the gain and driver stages, hand matched parts, audiophile WonderCaps, Roederstein metal film resistors, dual huge torroids, soft recovery rectifiers, fancy gold connectors, multiple current mirrors, Kimber Kable, silver solder, etc, etc. It's a great amp, was a labor of love, and it's still going strong. But I also built it before I discovered the reality of blind testing. So please don't insinuate I'm a DIY or audiophile virgin."
The quality of parts you used and the design approaches should result in an amplifier that sounds different from the run of the mill midfi you seem to be using as a base line in you comparisons. If these don't seem to be important factors, why not sell it, buy some good midfi, and use the money on something you enjoy. I don't think that everyone needs to use $75 caps and 28 dollar resistors but high quality parts do make good designs sound even better. I do a lot of in shopping in surpass stores and have found some excellent parts for very reasonable prices. A lot of the parts tend to be military surplus parts and I have found $35
resistors for under a dollar, and $35 caps for under $5. The large number of DIYers and part vendors out there have resulted in prices coming down for many parts. Investigation of the better grade industrial parts has made very good part selection possible with paying audiophile prices for them. The Internet also allows access the original vendors for things like silver wire, silver solder, and exotic cable. The forum has put together group buys for parts and PCB fabs. It is a community for the exchange of ideas, technical resources, and experiences.
"To bring yet another argument into this fold--especially for those of you who consider $8 capacitors in the signal chain to be a joke--I ask you to consider what most of the audio you listen to has gone through before it ever made it into your listening room. Yeah, there are a tiny handful of unusual audiophile recordings made on tweak equipment, but they won't even fill a small shelf--even if you did like all the obscure artists. 99.5% of what most of us listen to was recorded with regular old studio gear like the stuff made by Mackie."
Many feel distortion is cumulative. And that IMD products can progress geometrically i.e. processing distortion products can result in further distortion products when subject to nonlinearities in the playback equipment. The are many things about distortion, and the ears sensitivity to it, that we do not know. There are plenty of bad recordings out there. There are plenty of good ones too. I own dozens of recordings made of obscure artist (there is that snob appeal creeping in again) made by Keith Johnson and even local engineers with very tweaked equipment. Mr. Johnson is an extremely sharp engineer, hears extremely well, and built a point to point wired recording mixer with audiophile grade parts. Listening to his recordings done in the Meyerson hall in Dallas is quite educational since a have heard the same obscure artist perform in the hall live on many occasions and been in the monitor room to hear a live feed during a recording session. There are many more audiophile and excellent recording engineers than you think, and not all music recorded by audiophile labels is obscure drivel.
"Well this amp was built in the early 90's, and at that time, the components I used where some of the best available then. The "high-end" wasn't quite so obscene back then. The parts I used were some of the same ones the reviewers of the day were raving about in $20,000 commercial products."
It was plenty obscene then. The components you used were not the best available then (although good ones) and certainly not the best available now. There much better electrolytic caps now and not all of them are exotic with the corresponding price tag.
There are also better active parts and topologies now and this is a lot of what we talk about on the forum. Much of the Hype End audio industry is collapsing on it's self. The magazines advertising rates, reviewer's egos and ineptitude, and escalating prices to see the market would bear; have reached the limits and created the inevitable backlash. Audio is returning to the realm of the hobbyist, both kit builder and DIYer. The Web has made huge contribution to this movement. It's influence on easily access to technical information, the availability of inexpensive PC based simulation, sound card based measurement tools, and the comparison of experiences with people all over the globe make it fun and worthwhile experience. I don't believe every claim
made but I refuse disbelieve them all either. I have heard some amazing things from audio playback systems as the result of efforts by myself, many dedicated audiophiles, and designers. All outside the established mainstream commercial audio world. A lot of this was based on observations that produced results contrary to my expectations at the time. Many advancements in amplifiers and preamplifiers came from the efforts of people in other disciplines like mechanical engineering, material science, physics, optics, and RF design that happened to be audiophiles.
It has taught me to look in much more detail at the problems and measurements in other engineering projects and has given me the edge in understanding some of the more subtle things going on in a circuit. The really good engineers I have worked with, have this desire to get beyond what they know, and to look at secondary effects like thermal, vibration, and RFI immunity influence on circuits in which they were thought were too minor to be of significance. Looking for these subtitles and understanding more about the problem than the minimum knowledge required, is what separated the good engineers from the hacks.
I think the problem of the disparity between the listening experience and what we measure, is not because people imagine what they hear. It is the fact that the measurements we make are not adequate to describe these differences. As long as the people that listen are described as delusional, and the conventional engineering methods are trusted as authoritative, this impasse will remain. The measurements you describe are not even rigorous. Instruments and methods of testing orders of magnitude more sensitive than what you mention exist and are in common use in fields as non esoteric as telecom.
I heard way to many differences and know of too many circuit interactions and thermal, vibrational, and material related effects in passive components to think any of this is anywhere near as simple as the methods you propose can resolve.
I don't understand your zeal on sticking to this dogma of simple measurements as it doesn't even serve to enhance your knowledge as an engineer or pleasure as a listener. This seems only to be of service to those unable or unwilling to investigate these sonic differences, or to reinforce their egos as academics or engineers. I am not sure that double blind test cannot be useful. I believe that it would require the rigorous construction of a switch box with the same or better resolution as the equipment under test, the use of subjects with listening abilities, real familiarity the system and its variability. These are the methodologies used by serious high end designers and are as important as the level matching and double blind requirements of the test. The test should designed with the goal demonstrating the sonic differences between amplifiers with level matching rather than the goal to get them to sound the same.
In light of all these considerations, I refuse to let someone to tell me what to hear or in this case what not to hear, and how not to hear it. In fact I would dare say our endeavor is to describe what we hear, how we achieved it, and to explore the technical reasons for this sonic differences. This is a much more challenging, rewarding, and educational task and will improve the state of the art. What will the converse achieve, other than saving money and requiring less effort? It seems to me achieve stagnation, indiference, and dissapoint. You hardly seem enthusiastic about music or audio. Are you a burnout here to share the misery? We really appreciate that contribution.
I think your are confusing art and science with commerce and complacency.
Reviewer's opinions and cost of components.......
This seems to be just the type of questionable influences I mentioned in my post.
"I designed and built a high-end dual mono, fully symmetrical power amp. It has regulated higher voltage rails for the gain and driver stages, hand matched parts, audiophile WonderCaps, Roederstein metal film resistors, dual huge torroids, soft recovery rectifiers, fancy gold connectors, multiple current mirrors, Kimber Kable, silver solder, etc, etc. It's a great amp, was a labor of love, and it's still going strong. But I also built it before I discovered the reality of blind testing. So please don't insinuate I'm a DIY or audiophile virgin."
The quality of parts you used and the design approaches should result in an amplifier that sounds different from the run of the mill midfi you seem to be using as a base line in you comparisons. If these don't seem to be important factors, why not sell it, buy some good midfi, and use the money on something you enjoy. I don't think that everyone needs to use $75 caps and 28 dollar resistors but high quality parts do make good designs sound even better. I do a lot of in shopping in surpass stores and have found some excellent parts for very reasonable prices. A lot of the parts tend to be military surplus parts and I have found $35
resistors for under a dollar, and $35 caps for under $5. The large number of DIYers and part vendors out there have resulted in prices coming down for many parts. Investigation of the better grade industrial parts has made very good part selection possible with paying audiophile prices for them. The Internet also allows access the original vendors for things like silver wire, silver solder, and exotic cable. The forum has put together group buys for parts and PCB fabs. It is a community for the exchange of ideas, technical resources, and experiences.
"To bring yet another argument into this fold--especially for those of you who consider $8 capacitors in the signal chain to be a joke--I ask you to consider what most of the audio you listen to has gone through before it ever made it into your listening room. Yeah, there are a tiny handful of unusual audiophile recordings made on tweak equipment, but they won't even fill a small shelf--even if you did like all the obscure artists. 99.5% of what most of us listen to was recorded with regular old studio gear like the stuff made by Mackie."
Many feel distortion is cumulative. And that IMD products can progress geometrically i.e. processing distortion products can result in further distortion products when subject to nonlinearities in the playback equipment. The are many things about distortion, and the ears sensitivity to it, that we do not know. There are plenty of bad recordings out there. There are plenty of good ones too. I own dozens of recordings made of obscure artist (there is that snob appeal creeping in again) made by Keith Johnson and even local engineers with very tweaked equipment. Mr. Johnson is an extremely sharp engineer, hears extremely well, and built a point to point wired recording mixer with audiophile grade parts. Listening to his recordings done in the Meyerson hall in Dallas is quite educational since a have heard the same obscure artist perform in the hall live on many occasions and been in the monitor room to hear a live feed during a recording session. There are many more audiophile and excellent recording engineers than you think, and not all music recorded by audiophile labels is obscure drivel.
"Well this amp was built in the early 90's, and at that time, the components I used where some of the best available then. The "high-end" wasn't quite so obscene back then. The parts I used were some of the same ones the reviewers of the day were raving about in $20,000 commercial products."
It was plenty obscene then. The components you used were not the best available then (although good ones) and certainly not the best available now. There much better electrolytic caps now and not all of them are exotic with the corresponding price tag.
There are also better active parts and topologies now and this is a lot of what we talk about on the forum. Much of the Hype End audio industry is collapsing on it's self. The magazines advertising rates, reviewer's egos and ineptitude, and escalating prices to see the market would bear; have reached the limits and created the inevitable backlash. Audio is returning to the realm of the hobbyist, both kit builder and DIYer. The Web has made huge contribution to this movement. It's influence on easily access to technical information, the availability of inexpensive PC based simulation, sound card based measurement tools, and the comparison of experiences with people all over the globe make it fun and worthwhile experience. I don't believe every claim
made but I refuse disbelieve them all either. I have heard some amazing things from audio playback systems as the result of efforts by myself, many dedicated audiophiles, and designers. All outside the established mainstream commercial audio world. A lot of this was based on observations that produced results contrary to my expectations at the time. Many advancements in amplifiers and preamplifiers came from the efforts of people in other disciplines like mechanical engineering, material science, physics, optics, and RF design that happened to be audiophiles.
It has taught me to look in much more detail at the problems and measurements in other engineering projects and has given me the edge in understanding some of the more subtle things going on in a circuit. The really good engineers I have worked with, have this desire to get beyond what they know, and to look at secondary effects like thermal, vibration, and RFI immunity influence on circuits in which they were thought were too minor to be of significance. Looking for these subtitles and understanding more about the problem than the minimum knowledge required, is what separated the good engineers from the hacks.
I think the problem of the disparity between the listening experience and what we measure, is not because people imagine what they hear. It is the fact that the measurements we make are not adequate to describe these differences. As long as the people that listen are described as delusional, and the conventional engineering methods are trusted as authoritative, this impasse will remain. The measurements you describe are not even rigorous. Instruments and methods of testing orders of magnitude more sensitive than what you mention exist and are in common use in fields as non esoteric as telecom.
I heard way to many differences and know of too many circuit interactions and thermal, vibrational, and material related effects in passive components to think any of this is anywhere near as simple as the methods you propose can resolve.
I don't understand your zeal on sticking to this dogma of simple measurements as it doesn't even serve to enhance your knowledge as an engineer or pleasure as a listener. This seems only to be of service to those unable or unwilling to investigate these sonic differences, or to reinforce their egos as academics or engineers. I am not sure that double blind test cannot be useful. I believe that it would require the rigorous construction of a switch box with the same or better resolution as the equipment under test, the use of subjects with listening abilities, real familiarity the system and its variability. These are the methodologies used by serious high end designers and are as important as the level matching and double blind requirements of the test. The test should designed with the goal demonstrating the sonic differences between amplifiers with level matching rather than the goal to get them to sound the same.
In light of all these considerations, I refuse to let someone to tell me what to hear or in this case what not to hear, and how not to hear it. In fact I would dare say our endeavor is to describe what we hear, how we achieved it, and to explore the technical reasons for this sonic differences. This is a much more challenging, rewarding, and educational task and will improve the state of the art. What will the converse achieve, other than saving money and requiring less effort? It seems to me achieve stagnation, indiference, and dissapoint. You hardly seem enthusiastic about music or audio. Are you a burnout here to share the misery? We really appreciate that contribution.
I think your are confusing art and science with commerce and complacency.
"I do a lot of in shopping in surpass stores and have found some excellent parts for very reasonable prices. A lot of the parts tend to be military surplus parts and I have found $35
resistors for under a dollar, and $35 caps for under $5. "
Fred, stop rubbing my face in it. We got it, you found a great surplus store you are dying to tell us where it is, but you can't. Just as any mushroom or truffle picker in Italy or France wouldn't reveal their spots.
I'll have to hire a PI.
resistors for under a dollar, and $35 caps for under $5. "
Fred, stop rubbing my face in it.
We got it, you found a great surplus store you are dying to tell us where it is, but you can't. Just as any mushroom or truffle picker in Italy or France wouldn't reveal their spots. I'll have to hire a PI.
I disagree.
I agree that a violin itself is the flesh and blood experience. But why should I want to add new instruments to those of the musicians who's CD I just bought? Do I not like their performance? Does my talent exceed theirs?
No. I want my hifi system to REcreate the experience contained on the CD, not to embellish it or deminish it. And I am confident that a system that does this perfectly will not be found wanting for any nuance, any body, any soul, any vigour nor any subtlety.
But of course it is true that all amps are imperfect recreators and some combinations of imperfections sound more satisfying than others. But this is what we are talking about: imperfections make for a lifeless product. Don't make the mistake of thinking that accuracy of amplification is somehow causal of disatisfaction. It isn't. The cause of disatisfaction in this respect is due to incorrectly assuming something is accurate.
Most of us have no way to judge how accurate something is except for our own aural judgement. It is a pretty good measure and certainly a measure, if followed, will lead to our own personal satisfaction. So trust it.
We have all been told that current, published, engineering measurement results are poorly correlated to sound quality. So accept this and ignore published results. If you are designing and need a more effective/efficient way to judge improvements then look at all the published measurment methods, discard them, and develop your own from scratch. Otherwise you risk becoming self-deceived. You too will look at the perfectly flat group delay response and tell others the amp sounds good as a result.
Think about how our ears/brains work. How do they hear things. How can we make a test that reveals signal components that our ears will hear? It's really as simple as that.
blind taste tests
Boy,
I am enjoying this thread.
This is one of those topics that will never get resolved. A mix of scientifically measuring subjectivity. And then trying to talk about it.
I'd like to take a swat at the beehive by adding this:
I think that you need to look at the whole system when doing these test. A rigorous test would include performing blind listening on a component in one system, then repeating the test in different systems. I think that a given set of speakers can make amplifiers sound the same. For example, would two different amplifiers drive a pair of nice electrostatics the way they would drive a nice pair of 2-way dynamics? Or, for that matter, a multi-driver system?
Food for thought.
Vic
Boy,
I am enjoying this thread.
This is one of those topics that will never get resolved. A mix of scientifically measuring subjectivity. And then trying to talk about it.
I'd like to take a swat at the beehive by adding this:
I think that you need to look at the whole system when doing these test. A rigorous test would include performing blind listening on a component in one system, then repeating the test in different systems. I think that a given set of speakers can make amplifiers sound the same. For example, would two different amplifiers drive a pair of nice electrostatics the way they would drive a nice pair of 2-way dynamics? Or, for that matter, a multi-driver system?
Food for thought.
Vic
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