Re: Re: Re: amps - the not-so-great debate
Me, i'd just like to see a "single double-blind, scientifically and statistically properly arranged test" wrt audio... i haven't seen one yet. Certainly the ABX test is not (as an estemmed member with Statistic credentials pointed out, the beta is too high for it to be valid)
We are unfortunately in a time & space where most of those hawking blind tests are deeper into the snake oil than the legitimate snake oil dealers.
As to Quad 303s... a good amp in its day, but doesn't hold up under scrutiny today (i've owned well over a dozen of these and recently put one thru its paces)
At least with those little SE EL84 amps there was potential lurking inside... we have a couple quite listenable amps with iron donated by these (of course you need a speaker with a simple load, and adequate efficiency)
dave
tlparker said:
Me, i'd just like to see a "single double-blind, scientifically and statistically properly arranged test" wrt audio... i haven't seen one yet. Certainly the ABX test is not (as an estemmed member with Statistic credentials pointed out, the beta is too high for it to be valid)
We are unfortunately in a time & space where most of those hawking blind tests are deeper into the snake oil than the legitimate snake oil dealers.
As to Quad 303s... a good amp in its day, but doesn't hold up under scrutiny today (i've owned well over a dozen of these and recently put one thru its paces)
At least with those little SE EL84 amps there was potential lurking inside... we have a couple quite listenable amps with iron donated by these (of course you need a speaker with a simple load, and adequate efficiency)
dave
Re: Re: Re: Re: amps - the not-so-great debate
To emphasize a point SY made... an amplifier cannot be considered divorced from driving a real speaker and an 8 ohm resistor bears little in common with a speaker.
For instance, those nice little SE EL84 amps turn to yuk if faced by an XO comprised of much more than a single cap (fortunately for me, i'm quite happy listening to my 1-way speakers)
dave
planet10 said:
To emphasize a point SY made... an amplifier cannot be considered divorced from driving a real speaker and an 8 ohm resistor bears little in common with a speaker.
For instance, those nice little SE EL84 amps turn to yuk if faced by an XO comprised of much more than a single cap (fortunately for me, i'm quite happy listening to my 1-way speakers)
dave
Mr Parker;
Since you felt it pertinent to quote from your curriculum vitae, you should know that many members of this forum have been involved in combinations of the audio "hobby" and retailing/servicing/marketing of same for more years that you've been alive. Not all of us have advanced engineering , accounting or marketing degrees - just a lot of life experience.
If nothing else, these extra decades allow for a historical perspective that you might lack, in terms of first hand enjoyment of the "progress" made during the explosion of SS designs of the late 60's to mid 70's, as well as the results of blind acceptance by many of the "virtues" of scientific methods used to design and test audio gear.
Music means a lot of things to different people - believe it or not, some just don't get it. My wife for example, rarely tolerates any of my favorites, and doesn't comprehend the concept of what I'd refer to as "active" listening. To her music is either "background" or it's "noise" - needless to say we don't attend too many live concerts together, and I can assure you she's just as happy with the sound of her Sony ghetto blaster on the sundeck as with my modestly decent hi-fi. It's not that she can't hear the difference, she just couldn't care less (but just forget to polish the crystal wine glasses out of the dishwasher and watch out)
But many of us care far more about the emotional content of human voice, and the sometimes abstract time/space illusion of instrumentals, than for how any of the gear measures. If that makes us subjectivists, fine.
Don't forget that active listening to music reproduced by an audio system entails a voluntary suspension of disbelief.
Anyone who can develop a testing methodology that can reliably predict the size (or lack ) of smile on all listeners' faces will earn a huge amount of respect and admiration - but I'm not holding my breath.
As for the worst sounding big amp of the 70's, I think the BGW 750 and 1000 should be on that short list as well. The early Crown amps (DC300/D150) were not as "rip-your face off" terrible as the IC150 pre-amp.
Since you felt it pertinent to quote from your curriculum vitae, you should know that many members of this forum have been involved in combinations of the audio "hobby" and retailing/servicing/marketing of same for more years that you've been alive. Not all of us have advanced engineering , accounting or marketing degrees - just a lot of life experience.
If nothing else, these extra decades allow for a historical perspective that you might lack, in terms of first hand enjoyment of the "progress" made during the explosion of SS designs of the late 60's to mid 70's, as well as the results of blind acceptance by many of the "virtues" of scientific methods used to design and test audio gear.
Music means a lot of things to different people - believe it or not, some just don't get it. My wife for example, rarely tolerates any of my favorites, and doesn't comprehend the concept of what I'd refer to as "active" listening. To her music is either "background" or it's "noise" - needless to say we don't attend too many live concerts together, and I can assure you she's just as happy with the sound of her Sony ghetto blaster on the sundeck as with my modestly decent hi-fi. It's not that she can't hear the difference, she just couldn't care less (but just forget to polish the crystal wine glasses out of the dishwasher and watch out)
But many of us care far more about the emotional content of human voice, and the sometimes abstract time/space illusion of instrumentals, than for how any of the gear measures. If that makes us subjectivists, fine.
Don't forget that active listening to music reproduced by an audio system entails a voluntary suspension of disbelief.
Anyone who can develop a testing methodology that can reliably predict the size (or lack ) of smile on all listeners' faces will earn a huge amount of respect and admiration - but I'm not holding my breath.
As for the worst sounding big amp of the 70's, I think the BGW 750 and 1000 should be on that short list as well. The early Crown amps (DC300/D150) were not as "rip-your face off" terrible as the IC150 pre-amp.
I will second that re the experience
I own in my collection a bgw 750 not the best I have ever heard but not the worst
I just love my phase linear 400b with my B+W DM2A spk its allready blown up once but I have rebuilt it when it was designed and released i can remember being in awe of all that power at that time
I also have a crown dc 300a its a nice power amp
I have most of the 70/80 amps radfords ,sugdens /leaks ,quads Trio harman Rodgers Armstrong Bryan Crimson
the list goes on and on I can say most positively there is no one best amp or combination each is differrent I love them all
My hobby is now mostly restoring these things to date I have yet to sell any on so I have no financial interest !I go to work for my monies
35 years of experience in listening designing and building both valve and solid state amps have enabled me to realise that no one has the complete solution
I am left in awe of some of these early designers who produced so much from so little
But I must admit I do get fed up of people on about there latest esoteric BLAH BlaH Blah
It seems to me they are just trying to Pose
Regards Trev
I own in my collection a bgw 750 not the best I have ever heard but not the worst
I just love my phase linear 400b with my B+W DM2A spk its allready blown up once but I have rebuilt it when it was designed and released i can remember being in awe of all that power at that time
I also have a crown dc 300a its a nice power amp
I have most of the 70/80 amps radfords ,sugdens /leaks ,quads Trio harman Rodgers Armstrong Bryan Crimson
the list goes on and on I can say most positively there is no one best amp or combination each is differrent I love them all
My hobby is now mostly restoring these things to date I have yet to sell any on so I have no financial interest !I go to work for my monies
35 years of experience in listening designing and building both valve and solid state amps have enabled me to realise that no one has the complete solution
I am left in awe of some of these early designers who produced so much from so little
But I must admit I do get fed up of people on about there latest esoteric BLAH BlaH Blah
It seems to me they are just trying to Pose
Regards Trev
I think people dismiss certain amps because of the SPEAKERS they're driving. Just HOW can you really truely judge an amp by listening to it through a flappy cone of paper glued to a coil?
Maybe it's the high damping factor of big 70s SS amps that makes tweeters on some speakers produce exagerated treble, so people mistakenly label this as 'crossover distortion' when it's just their tweeters spazzing out over the fact that the amplifier is acting as a nearly a pure voltage source.
I will admit, my HiFi is being driven by your stereotypical 70s monster amps (radford ZD100s "Zero Distortion") and they DO sound harsh but I put this down to my rubbish speakers.
Maybe it's the high damping factor of big 70s SS amps that makes tweeters on some speakers produce exagerated treble, so people mistakenly label this as 'crossover distortion' when it's just their tweeters spazzing out over the fact that the amplifier is acting as a nearly a pure voltage source.
I will admit, my HiFi is being driven by your stereotypical 70s monster amps (radford ZD100s "Zero Distortion") and they DO sound harsh but I put this down to my rubbish speakers.
bigwill said:
Having measured most of the amps of the 70's, I can say that
the high powered quasi-complementary examples did tend to
have big crossover notches, the kind of thing you really don't
see today. They were sold on the basis of the average distortion
at higher power levels which disguised this flaw.
While on the topic, in my opinion the reliability problems of
the Phase Linear and other early high power amps was mostly
a second breakdown issue. By the 80's, designers wised up
about this and RCA and Motorola were making chips with better
second breakdown.
I hope my amp doesn't have any crossover distortion! Probably not, I think radford was a good designerNo offense tlparker, but perhaps you are not a true audiophile in the purest sense. I do not mean that as an insult, but simply as a statement of potential fact. I am assuming you have a technical background. Sometime it is difficult to let go of old knowledge, i.e. like THD is king. Remember learned people used to think the earth was the center of the universe and was flat.
Perhaps you just have not had an epiphany moment that would make you understand that things you think would not make a difference actually do.
Getting back to that scientific A/B test. If I was to set up two amps and switch them imperceptibly you are correct, in many cases most people would not notice a difference. There are two issues here. One, many people on these forums do not fall into the "most people" category. Two, this is not an effective or accurate way to do an A/B test on audio equipment.
A better way is to let the listener pick music they are intimately familiar with and then let them listen to it extensively on the two different set ups. Over time, they will start to notice items that characterize each set up. Then you do the A/B test with the same music letting them listen extensively. Experienced and discriminating listeners will pick up those characteristics they noticed in the "conditioning" phase. As per your posts, this should not be possible.
I had my epiphany many years ago with a set of interconnects between a pre-amp and an amplifier. My significant engineering background told me this should not be possible. However, over an evening of listening, I was able to reliably (80%+) pick which cables were being used. That was not luck. I was able to notice some characteristic differences in the way the two sounded. As an engineer, I did not believe that a simple interconnect should make such a difference. However, as I heard the difference, it must have been there. I decided to delve more into the causes and after looking at the output of the pre-amp and the input to the amp, I decided that it was likely interactions with the cables and not the cable per-se that made the biggest difference. Some playing around with circuits and voila, I no longer could tell the difference.
There is a simple argument that shows the lack of value of THD. Take two sine waves, one the original and one a perfectly delayed version of the other. Assume the input to the amp is just one sine wave and the output is the sum of the original sine wave and a perfectly delayed version of it? What will the THD of the output be?
There are a lot of items in high end audio that appear to be snake oil. Some of them truly are. Some appear to be snake oil, but likely fix other design flaws within the system. Take for example these $500 AC power cords. Are they snake oil? Not necessarily. They can potentially solve subtle issues or design flaws with grounding and shielding in either individual pieces of equipment or the system as it is put together. Do I have $500 power cords in my system? Heck no! However, I do have 6 guage copper wire connecting the chassis of all my audio equipment and then connected as a star ground. I think it cost $20 total for all 6 pieces. I also have a well filtered AC supply for my system. That was another few hundred for the whole system and will also protect my investment from nasties on the AC line so well worth it.
I know it is hard to keep an open mind when you personally have not heard the subtle differences that do exist. Perhaps there is someone on here close to you that can walk you through an evening of music listening so that you can hear these differences. I will gladly donate my mid-80's vintage CD player for the event.
Alvaius
Perhaps you just have not had an epiphany moment that would make you understand that things you think would not make a difference actually do.
Getting back to that scientific A/B test. If I was to set up two amps and switch them imperceptibly you are correct, in many cases most people would not notice a difference. There are two issues here. One, many people on these forums do not fall into the "most people" category. Two, this is not an effective or accurate way to do an A/B test on audio equipment.
A better way is to let the listener pick music they are intimately familiar with and then let them listen to it extensively on the two different set ups. Over time, they will start to notice items that characterize each set up. Then you do the A/B test with the same music letting them listen extensively. Experienced and discriminating listeners will pick up those characteristics they noticed in the "conditioning" phase. As per your posts, this should not be possible.
I had my epiphany many years ago with a set of interconnects between a pre-amp and an amplifier. My significant engineering background told me this should not be possible. However, over an evening of listening, I was able to reliably (80%+) pick which cables were being used. That was not luck. I was able to notice some characteristic differences in the way the two sounded. As an engineer, I did not believe that a simple interconnect should make such a difference. However, as I heard the difference, it must have been there. I decided to delve more into the causes and after looking at the output of the pre-amp and the input to the amp, I decided that it was likely interactions with the cables and not the cable per-se that made the biggest difference. Some playing around with circuits and voila, I no longer could tell the difference.
There is a simple argument that shows the lack of value of THD. Take two sine waves, one the original and one a perfectly delayed version of the other. Assume the input to the amp is just one sine wave and the output is the sum of the original sine wave and a perfectly delayed version of it? What will the THD of the output be?
There are a lot of items in high end audio that appear to be snake oil. Some of them truly are. Some appear to be snake oil, but likely fix other design flaws within the system. Take for example these $500 AC power cords. Are they snake oil? Not necessarily. They can potentially solve subtle issues or design flaws with grounding and shielding in either individual pieces of equipment or the system as it is put together. Do I have $500 power cords in my system? Heck no! However, I do have 6 guage copper wire connecting the chassis of all my audio equipment and then connected as a star ground. I think it cost $20 total for all 6 pieces. I also have a well filtered AC supply for my system. That was another few hundred for the whole system and will also protect my investment from nasties on the AC line so well worth it.
I know it is hard to keep an open mind when you personally have not heard the subtle differences that do exist. Perhaps there is someone on here close to you that can walk you through an evening of music listening so that you can hear these differences. I will gladly donate my mid-80's vintage CD player for the event.
Alvaius
audiophile? I would hope not
No indeed, I consider the term an insult. Now, diy audio for fanatics, that's another matter.
To me it comes mostly down to "audiophiles" caring far too much about form and far too little about function. This is indeed a group I would prefer not be be considered part of, thanks.
No indeed, I consider the term an insult. Now, diy audio for fanatics, that's another matter.
To me it comes mostly down to "audiophiles" caring far too much about form and far too little about function. This is indeed a group I would prefer not be be considered part of, thanks.
alvaius said:
Wow!
There's an audiophile.
Then there's a true audiophile.
Then there's a pure audiophile.
Then there's an audiophile in the purest sense.
Double wow!
One can have listened to and/or tested thousands of amplifiers and unless all the environmental conditions were exactly the same, including the mood of the listener, for each and every audition, the results of these evaluations whether subjective or objective might just as well be printed on toilet paper for all they are worth.
The most important factor to be aware of is that the brain has this innate capacity to fill in the blanks in all aspects of our perception whether physical, mental or emotional. (Whence the expression: Rose tinted glasses.) We see and hear what we want to see and hear. You'll understand when you have another epiphany.
One of my favorite sites:
http://www.theaudiocritic.com
http://www.theaudiocritic.com/cwo/Sample_Articles/
I now have to go and remove my hip-boots.
fred p.
ppfred said:
Don't forget the Frugal-phile(tm) ... it is much more of a challenge to put together a musically satisfying system for next to nothing than to just throw money at the probelm (often with fleeting satisfaction)
One of the funniest satires i've ever read ... and they do it so well you are left with a fleeting thot that they may actaully be serious.
dave
alvaius said:
Hi Alvaius,
I think there are two pairs of issues here.
First pair: We should make a distinction between enjoying listening to music, and designing amplifiers.
Example: When I enjoy music, I enjoy the whole environment. Whether I like it or not, I enjoy the sound, the rhithm, the flow of tempo, but also the fact that I built those beautiful speakers. The anticipation that I will go out later for a nice dinner with a stunning blonde certainly add to my well being. In other words, it is nonsense to try to separate the THD at 10 watts of my amp from the general perception.
But if I need to desing the next amplifier, I need to try to separate out all those other factors because I try (if I'm half-way serious about this) to design something that will faithfully reproduce whatever it is offered.
There are at least two ways to verify that I am nearing my goal. One is to measure how faithfull that amp reproduces the input signal. I agree that THD is probably not the best measurement stick, but we are talking principles here.
The other is to listen to the amp and compare it to a known good or accepted amp. That is where listening tests come in. And because of my goal in this test (and the reviewers should have the same goal if they are honest) is to judge the SOUND, not the color, weight, brand penetration or price. And we all know that these extraneous factors influence your perception big time. Also the perception from these seasoned testers/reviewers. You would have to be an alien to escape this common human trait.
However you crumble the cookie, you need (double) blind testing.
Now we have a problem. Because in many double blind tests, there is no perceptible difference! Ahh, you say, but you should test differently! First you do sighted tests to identify the diferences, then double blind to confirm them (I am parafrasing but I think this is the gist of your comments).
Pardon me, but that is hogwash. First of all, it has been done over and over again. Many people have stated big differences between sighted equipment that COULD NOT be confirmed in blind tests. There have been blind tests with second-interval switching on one side of the spectrum, and blind tests where tester had complete control over interval length, music, you name it. Same result.
Behind it all is your conviction that the diferences are there, that it just is a matter of finding a test that confirms them.
That is circular reasoning at best. If you are serious and honest, you accept NOTHING in advance until there are some repeatable, statistically valid tests that confirm the differences.
Blind testers go out of their way to adapt their tests to criticism that it took too long, too short, to many people, wrong type of people, wrong speakers, etc. Still no results. Still more criticism.
On the other hand, any halfwit with bananbox speakers and an underbiased amp reports strong differences in sound between red and blue wire and throngs of people accept it as gospel.
This is indeed a sad state of affairs for our great hobby.
Jan Didden
Err, you're missing the point, deep down, they ARE serious, they just don't take themselves as seriously as (heavenly music begins) *Audiophiles* (fade out). But then, anyone who cranks out little pionted wooden doo-hickeys on a lathe and then tells people to cut up their speakers and insert the little piece of wood oughta understand this perfectly.
planet10 said:
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