Don't know where you read that?
Here is a quote from the article:
"The basic cause of the difference in tube and transistor sound is the weighting of harmonic distortion components in the amplifier overload region. Transistor amplifiers exhibit a strong component of third harmonic distortion when driven into overload. This harmonic produces a "covered" sound, giving the recording a restricted quality."
That is the essence to me as well. He has put to paper what is evident.
Mostly the heated discussion then attacks his intellect and all kinds of side issues.
But THD is still accepted, while for audio amplifiers it is irrelevant to say the least?
But Cheever was ofcourse not the first to argue that. Here is what Lynn Olson had to say on that...
Boggles the mind.
Another interesting thing is ofcourse that Mr. Hamm (Does anyone know if he is still alive?) Tested tubes that had much higher distortion and where less linear than earlier tubes!!
Richard C said:
I have suggested similar points as well. In the future, all amps will be tested by every single piece of music under 1w, 1.1w, 1.2w, ..., all the way to full power.
so each amp will come with a Library of Congress-sized distortion spec. book. In it, it has distortion figures for Spears', U2', Clapton's and other artists' recordings and their distortion figures.
That way, everyone is happy.
millwood said:so each amp will come with a Library of Congress-sized distortion spec. book. In it, it has distortion figures for Spears', U2', Clapton's and other artists' recordings and their distortion figures.
Wait, doesn't room acoustics have a lot to do with how speakers sound? what bearing does lab measurements have on real life sound? None.
so we should also measure how speakers sound in every home, and every room in every home, for meaningful measurements.
where does this end? For those who insist that sine wave testing of audio equipment is not meaningful, can you provide a meaningful measurement that doesn't suffer from any critism?
It certainly is not MEANINGFUL, but it might be useful. And even if it was useful, once you have measured it...does that guarantee that it sounds good? Ofcourse not!
Ehm no..measurements will always be just that : useful. It is not the measurements by the way that are criticized, but the interpretation and application thereof. Feedback can fool measurements but not the human ear!
Have you really feel passion in your life?
When you are in real love, not the sex love, because this one is hormon's driven.... i am talking with serious passion, the one survived 30, or 40, sometimes 50 years long?
Having the passion person together you or not?
If you someday, really feel passion, you can remember that brain plays music for you......a brain creation, no instruments playing, the noise around your disappear, the persons with you evaporate immediatly, you do not see or hear nothing but the loved girl.... all your body feel that!.... If you do not felt this, do not trow amplifiers trash......maybe the wrong thing going to trash?
If brain can play music........ so, he make a translation of audio pressure inside hears, the transducer is a hammer, and some cells that liberate energy when pushed..... this is audio, translated to electrochemical sensations.... this way, alike a CD player understand hi and low levels and re-construct audio... creating sinusoidal alike (only alike... real.....less alike than real) sounds....brain has this capacity too.
Let's see a man with a damn old transistor small radio, glued into his ears!..... loud an dirty sound.....he dreaming and smiling happy.... is easy to think he is an animal, a beast, a awfull stupid Neanderthall, Cro-Magnon, fool, undeveloped, poor, .... everything you like to describe can be applied here. All illusions related your ideas..... and all illusions the sound he is listening too.
Our brains, together ears, have the adaptation capacity, this way, everysound, till the old you turn manifolds, can be good if you like the music, if you like the life, if you are in love or if you are listening too long time...... this last idea is the main.... long time listening you repair....your fix....using brain..... you turn a damn sound with an anjo music.
Hallojoy send me a damn music...... my family hate it...... they told the man is drunk, the singer is drunk, and the language is awfull, seem to be stone aged music.....
- Please Carlos!..... reduce this music volume, please!
But they do not now i was loving the music.... do you know why?....because i like hallojoy ideas and spirit....music came from Sweden....he send me as a gift..... and i received as a gift.... i also learn the words and starting to sing in Swedish language.... family convinced i am crazy.... poor devil's they are.... i am sure about i am crazy a long time..... they spend 20 years to discover!!! hahaha!!!
So, this discussion is wonderfull, because we are not comparing nothing with nichst, zero compared to null, 6 to half dozen.... people expendind time looking to spectrum..... and some sets, are really Marcians!...no doubts, the exception is the ones, i knew two...... i am the third!.....that try to understand the feeling effects off this distortion and this other..... looking to wave forms distortions and try to put some of them.... the small distortion creators!.
-GO TO HELL CARLOS, DAMN S--T CRAZY GUY!
No!, i will not go, because maybe i already living in hell's place... take a look around you..... visit other countries........
The valve sound are easier translated, why?.... who knows!.... we now it is more pleasant sound... scope said it distorted a lot!....but all of us like it..... the one that not agree....make a long time blind testing..... a friend switching long time, same music.... the one you like......different days..... different results..... confused results, depends on your feelings are....had a strike today?.... what about the barbecue smelling from your neighboors kitchen? do you like this smell?..... 5 hours smelling?.... do you still like?.... and kids screaming?.... five hours screaming?.... are you good?....do you want to hear music?..... with this noise together?......but if SHE appear in front of you all sounds disappear.... all noises gonne!....how?.....BRAIN MAN!
Your friend's amplifiers, if no good, they are reasonable..... the competitors amplifiers are a damn noisy machine!...EMOTIONS MAN!
We are stupid...... not you..... the others..... we never could believe we are this or that.... always the others., the neighboors, the white ones, the yellow ones, the poor ones... the damn rich ones..... but we are so poor in knowledge that we use only a small part of the brains..... go to measurements.... the computer one.... and think, remember, calculate... feel things.... only small part actuate each time..... we do not use all we can.
People is constructing amplifiers with some active circuits, really in the audio patch way, and hundreds, or thousands transistors inside chips, controlling all thing.... is this stupid or not?....and circuits to correct distortion that was generated before.... and another circuit to correct the distortion generated by the undistortion controls.... and them.... things goes with this wake up dream.
Valve..... two or three tubes..... old chips, giant Penthodes, 5 in one.... and we discover how to integrated many transistor into a package?....my god!..... already discover in tubes.... integration, not small, not solid, but integrated!
Life is distorted, we listen harmonics generated all time, because sound waves are doing that in space.... send a sequence of stones i a lake, various points of the lake with waves.... see the result and think about it.... where's fidelity?..... how can the stupid diafragm of a speaker goes ahead and backwards same time.... and also shake small over it.....and making a 100 hertz strong tone..... at same time.... the second 10 hertz frequency we put to create "afraid efect" on human feelings...because earth quakes an natural disasters..... catastrophes are almost low in frequency..... the deep sea dragon from Japanese....Thor and his hammer!
All we have is no fidelity...just because, all this is filtered by your brain..... and if i do not like you....... bad filter........ hummmmm!...bad music!, bad sound, bad wiskie, all bad!
We are human beeings, not microfones, not scopes, not spectrum analisers..... and we are joined here, not because of sound amplifiers.....because of love.... feelings perceived by sounds, memories, love.
My discussion, your discussion, our discussion.....no result possible, because we already do not know 10 percent of our brain functions..... the technology was inspired in our knowledges about things...... to pump water.......heart pumps blood.... analogies where beeing made long , long time ago.... and now, whe are using 500 watts energy consumption..... a damn giant computer.... zilions of transistors...... to talk, having fun, the same way since the down of civilization people around the fire did that....not needed telephone lines, or satelites... to be joined inside on subject.
Paint you amplifier green if you like green, because music will be felt greenish..... feel, you are a living beeing.... feelings are the answer....Christ said, love one each other, in special the one you do not like!..... we have the key, the answer, no one following....no one uses the key..... i am not clever.... i delayed 30 years of my life to discover so simple things, THE MAN, told us so many times.
Put all your money together an try to buy love and passion.... try to understand hallojoy, call them back, as i want it here!
Carlos
When you are in real love, not the sex love, because this one is hormon's driven.... i am talking with serious passion, the one survived 30, or 40, sometimes 50 years long?
Having the passion person together you or not?
If you someday, really feel passion, you can remember that brain plays music for you......a brain creation, no instruments playing, the noise around your disappear, the persons with you evaporate immediatly, you do not see or hear nothing but the loved girl.... all your body feel that!.... If you do not felt this, do not trow amplifiers trash......maybe the wrong thing going to trash?
If brain can play music........ so, he make a translation of audio pressure inside hears, the transducer is a hammer, and some cells that liberate energy when pushed..... this is audio, translated to electrochemical sensations.... this way, alike a CD player understand hi and low levels and re-construct audio... creating sinusoidal alike (only alike... real.....less alike than real) sounds....brain has this capacity too.
Let's see a man with a damn old transistor small radio, glued into his ears!..... loud an dirty sound.....he dreaming and smiling happy.... is easy to think he is an animal, a beast, a awfull stupid Neanderthall, Cro-Magnon, fool, undeveloped, poor, .... everything you like to describe can be applied here. All illusions related your ideas..... and all illusions the sound he is listening too.
Our brains, together ears, have the adaptation capacity, this way, everysound, till the old you turn manifolds, can be good if you like the music, if you like the life, if you are in love or if you are listening too long time...... this last idea is the main.... long time listening you repair....your fix....using brain..... you turn a damn sound with an anjo music.
Hallojoy send me a damn music...... my family hate it...... they told the man is drunk, the singer is drunk, and the language is awfull, seem to be stone aged music.....
- Please Carlos!..... reduce this music volume, please!
But they do not now i was loving the music.... do you know why?....because i like hallojoy ideas and spirit....music came from Sweden....he send me as a gift..... and i received as a gift.... i also learn the words and starting to sing in Swedish language.... family convinced i am crazy.... poor devil's they are.... i am sure about i am crazy a long time..... they spend 20 years to discover!!! hahaha!!!
So, this discussion is wonderfull, because we are not comparing nothing with nichst, zero compared to null, 6 to half dozen.... people expendind time looking to spectrum..... and some sets, are really Marcians!...no doubts, the exception is the ones, i knew two...... i am the third!.....that try to understand the feeling effects off this distortion and this other..... looking to wave forms distortions and try to put some of them.... the small distortion creators!.
-GO TO HELL CARLOS, DAMN S--T CRAZY GUY!
No!, i will not go, because maybe i already living in hell's place... take a look around you..... visit other countries........
The valve sound are easier translated, why?.... who knows!.... we now it is more pleasant sound... scope said it distorted a lot!....but all of us like it..... the one that not agree....make a long time blind testing..... a friend switching long time, same music.... the one you like......different days..... different results..... confused results, depends on your feelings are....had a strike today?.... what about the barbecue smelling from your neighboors kitchen? do you like this smell?..... 5 hours smelling?.... do you still like?.... and kids screaming?.... five hours screaming?.... are you good?....do you want to hear music?..... with this noise together?......but if SHE appear in front of you all sounds disappear.... all noises gonne!....how?.....BRAIN MAN!
Your friend's amplifiers, if no good, they are reasonable..... the competitors amplifiers are a damn noisy machine!...EMOTIONS MAN!
We are stupid...... not you..... the others..... we never could believe we are this or that.... always the others., the neighboors, the white ones, the yellow ones, the poor ones... the damn rich ones..... but we are so poor in knowledge that we use only a small part of the brains..... go to measurements.... the computer one.... and think, remember, calculate... feel things.... only small part actuate each time..... we do not use all we can.
People is constructing amplifiers with some active circuits, really in the audio patch way, and hundreds, or thousands transistors inside chips, controlling all thing.... is this stupid or not?....and circuits to correct distortion that was generated before.... and another circuit to correct the distortion generated by the undistortion controls.... and them.... things goes with this wake up dream.
Valve..... two or three tubes..... old chips, giant Penthodes, 5 in one.... and we discover how to integrated many transistor into a package?....my god!..... already discover in tubes.... integration, not small, not solid, but integrated!
Life is distorted, we listen harmonics generated all time, because sound waves are doing that in space.... send a sequence of stones i a lake, various points of the lake with waves.... see the result and think about it.... where's fidelity?..... how can the stupid diafragm of a speaker goes ahead and backwards same time.... and also shake small over it.....and making a 100 hertz strong tone..... at same time.... the second 10 hertz frequency we put to create "afraid efect" on human feelings...because earth quakes an natural disasters..... catastrophes are almost low in frequency..... the deep sea dragon from Japanese....Thor and his hammer!
All we have is no fidelity...just because, all this is filtered by your brain..... and if i do not like you....... bad filter........ hummmmm!...bad music!, bad sound, bad wiskie, all bad!
We are human beeings, not microfones, not scopes, not spectrum analisers..... and we are joined here, not because of sound amplifiers.....because of love.... feelings perceived by sounds, memories, love.
My discussion, your discussion, our discussion.....no result possible, because we already do not know 10 percent of our brain functions..... the technology was inspired in our knowledges about things...... to pump water.......heart pumps blood.... analogies where beeing made long , long time ago.... and now, whe are using 500 watts energy consumption..... a damn giant computer.... zilions of transistors...... to talk, having fun, the same way since the down of civilization people around the fire did that....not needed telephone lines, or satelites... to be joined inside on subject.
Paint you amplifier green if you like green, because music will be felt greenish..... feel, you are a living beeing.... feelings are the answer....Christ said, love one each other, in special the one you do not like!..... we have the key, the answer, no one following....no one uses the key..... i am not clever.... i delayed 30 years of my life to discover so simple things, THE MAN, told us so many times.
Put all your money together an try to buy love and passion.... try to understand hallojoy, call them back, as i want it here!
Carlos
Generaly, a tube has a wider linear region vs a typical transistor, biasing is key. However, if the transistor's Q-point does not vary much, then it can have very linear operation over a small change. This means that the gain is reduced, so use more transistors. Who can make a power efficient discrete SS amp with very low distortion and a wide responce bandwidth just using a few transistors? I would be impressed to see it.
Sometimes complexity has its advantages. maybe this is why high end SS Hi Fi amps ARE so costly.
The high current BJT Hi-Fi circuit I am working on currently designing has become much more complex than originally sketched. It is hard to get clean linearity over a wide bandwidth and not be creating a space heater. I like using higher impeadences (except for output and drivers), less noise & faster operation. This design has now included hexfet switches to add a "Current boost" to the outputs above 60-70% to be able to make the harmonic spikes of a full range audio signal possible without exceeding the breakdown V of my 15$\pair high current audio drivers. 
ps. it is a good idea to use cheap generic outputs instead of good ones if you are designing you own circuit.
I would be impressed to see it. Sometimes complexity has its advantages. maybe this is why high end SS Hi Fi amps ARE so costly.
The high current BJT Hi-Fi circuit I am working on currently designing has become much more complex than originally sketched. It is hard to get clean linearity over a wide bandwidth and not be creating a space heater. I like using higher impeadences (except for output and drivers), less noise & faster operation. This design has now included hexfet switches to add a "Current boost" to the outputs above 60-70% to be able to make the harmonic spikes of a full range audio signal possible without exceeding the breakdown V of my 15$\pair high current audio drivers.
ps. it is a good idea to use cheap generic outputs instead of good ones if you are designing you own circuit.
"But howcome his "Blameless" power amp is not so popular? Anyone has built DougSelf's "Blameless" power amp? How does it sound?"
Actually, several of the Slones designs are essentially "Blameless". The "11.4" Slone is a good example. Slone adds two pole compensation, but that is discussed by Swlf in any case. Based on members on this forum (as well as myself) who have built an 11.4, they sound very nice, indeed. Actually, I would be hard pressed to say it "sounds" at all. By this I mean it has no obvious contribution to to the source material -- perhaps those with more refined listening skills could pick up something.
I expect Self's "Blameless" sound similarly. I can't count on the comments refering to problems with the V-I limiting except the Slone version doesn't seem to exhibit any similar problems. This may be due to a choice of different slopes which is determined by the value of the resistor that forms the rail reference. Self uses 12k while Slone uses 15k. In any case, it is easily modified ti the characteristic of the rest of the amp and has no bearing on the soundness of the topology otherwise.
Actually, several of the Slones designs are essentially "Blameless". The "11.4" Slone is a good example. Slone adds two pole compensation, but that is discussed by Swlf in any case. Based on members on this forum (as well as myself) who have built an 11.4, they sound very nice, indeed. Actually, I would be hard pressed to say it "sounds" at all. By this I mean it has no obvious contribution to to the source material -- perhaps those with more refined listening skills could pick up something.
I expect Self's "Blameless" sound similarly. I can't count on the comments refering to problems with the V-I limiting except the Slone version doesn't seem to exhibit any similar problems. This may be due to a choice of different slopes which is determined by the value of the resistor that forms the rail reference. Self uses 12k while Slone uses 15k. In any case, it is easily modified ti the characteristic of the rest of the amp and has no bearing on the soundness of the topology otherwise.
"Wait, doesn't room acoustics have a lot to do with how speakers sound? "
With regard to amp testing using real speakers, Ben Duncan has pointed out that in addition to the usual disadvantages of "real life" loads the following: The electromechanical action of the speaker itself is influenced by the room it is in. This means that the same test signal (sine, music, whatever) played at the same level through the same amps with the same length of speaker cable connected to the very same speaker -BUT- with the speaker in different sized/shaped rooms will generate different electrical measurements taken from the amp. I.e., the room has an influence on the speaker's impedance.
This is just one more reason why "real life" testing, as opposed to sine signals and dummy loads, sounds good in spirit but results in data that is difficult or impossible to use.
With regard to amp testing using real speakers, Ben Duncan has pointed out that in addition to the usual disadvantages of "real life" loads the following: The electromechanical action of the speaker itself is influenced by the room it is in. This means that the same test signal (sine, music, whatever) played at the same level through the same amps with the same length of speaker cable connected to the very same speaker -BUT- with the speaker in different sized/shaped rooms will generate different electrical measurements taken from the amp. I.e., the room has an influence on the speaker's impedance.
This is just one more reason why "real life" testing, as opposed to sine signals and dummy loads, sounds good in spirit but results in data that is difficult or impossible to use.
Maybe we gonna use a small plug in the skull base
This way, electric impulses will go directly.
Also, you will control some emotions.... when your boss died.... despite of smiling all the time.... you can press the button to be sad , and crying all the time, you will go to see the damn begining his travell to hell.
And after that, do not forget to push the "kind" button when you go to "support" her wife hohohô (sadic way)
Carlos
Carlos
This way, electric impulses will go directly.
Also, you will control some emotions.... when your boss died.... despite of smiling all the time.... you can press the button to be sad , and crying all the time, you will go to see the damn begining his travell to hell.
And after that, do not forget to push the "kind" button when you go to "support" her wife hohohô (sadic way)
Carlos
Carlos
mikee12345 said:whatabout the CHeever thesis,certainly it raises a few good points,but isnt the be all and end all ?
http://w3.mit.edu/cheever/www/cheever_thesis.pdf
The response to some one posting this is usualy rather heated
http://diyaudio.com/forums/showthread.php?postid=195349#post195349
sam9 said:
Absolutely correct. The "I don't listen to sine wave" crowd didn't understand that if specs are measured exactly to their environment, it would be completely meaningless to others. the purpose of a sine wave testing is so that the end results are indicative, but not exact replica, of real life performance.
Those sine-wave based specs are "proxies" or im-perfect indicators of real-life performance. so that we can compare across a broad range of products and infer how they would have performed in real life.
To get an exact measurement of real life performance, however, you would have to measure it in that particular "real life" environment.
Pjotr said:In the near future AP will supply sets of human listening panels with calibrated ears and trained to all kinds of music.
Cheers
But then how many of us listen with "caliberated ears"?
"So maybe religiously avoiding any distortions is a false path."
Zero distortion only occurs when the amp is unplugged.
This leaves open questions such as:
"Can distortion be driven so low that is indistinguishable from zero" (As a measurement? As percieved by a listener?)
"When asserting that the distrubution of harmonis is important, are we speaking of relative levels or absolute?" For instance which is better --
A: 2nd = 10% plus 3rd 1% or
B: 2nd = .0001% plus 3rd .001%
Etc, etc.
Zero distortion only occurs when the amp is unplugged.
This leaves open questions such as:
"Can distortion be driven so low that is indistinguishable from zero" (As a measurement? As percieved by a listener?)
"When asserting that the distrubution of harmonis is important, are we speaking of relative levels or absolute?" For instance which is better --
A: 2nd = 10% plus 3rd 1% or
B: 2nd = .0001% plus 3rd .001%
Etc, etc.
Hi,
Profile A would be the least objectionable. Not because of the absolute figures of distortion but because of the relative relationship between even and odd order harmonic distortion.
Which is another way of saying that THD figures are rather meaningless when expressed in percentages....
Cheers,
Profile A would be the least objectionable. Not because of the absolute figures of distortion but because of the relative relationship between even and odd order harmonic distortion.
Which is another way of saying that THD figures are rather meaningless when expressed in percentages....
Cheers,
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