I think I do get the technical stuff right is a matter of pride . I have friends with PHD's who look over with me when I get stuck . I think what I do better than many is persist and believe what measures correctly must be correct .
The guy I built my amp for will try to make of list of what I described as current drive speakers for amps like these . If not accurate as current drive as a mining electrical engineer it is something he can get his teeth into . The 211 A2 amp I will build is to close another bereavement . The first was my brother , I cannibalized an amp he rejected . My brother was classified by IQ as a genius . The amp he left me was not very good . It showed he had declined . I was able too tell my mother this . It brought her peace she said , for him to loose his powers further would have been more distressing than death . His death is a mystery to this day . He was 48 . My mother said to him shortly before he died " What would Nigel do without you ? He has surpassed me mum so he would be OK . " Truth is he was declining and perhaps I has surpassed the him of that moment . He burnt bright but short . I write him emails . I wish I had the pass word as I would use his address . It was valvedabbler
The A2 was to be for Tom Fletcher of Nottingham Analogue , he died just as it was finished . Tom F gave my friend a circuit to try ( not A2 , hum bucked , not DC heater , this I have to see ) . It uses 211 valves . My friend didn't like the amp over 300 B . As I am not the 300 B greatest fan I am shock ( and probably will be ) a 211 is worse . Will will change that and get some watts I hope . Some guy said IM distortion can be reduced if A2 is correctly used . What have I got to loose except the obvious ." Careful with that axe Eugine " .
Personally I do think there is a spiritual journey with what we do . I saw an 8F locomotive for the first time the other day . In want one . Spiritual is just knowing your goal and never accepting less than your best . Going to concerts helps . It is a technical parameter .
Does anyone know this . In Nottingham it is said some EL 34 's pure triode were made . We guess these would be a little like ones favorite PX25 ?
What I have never said is I was a friend of Mr Kondo . We didn't speak each others language so it was going to meals together and me lending turntables ( Terry O'Sullivan was the one who introduced me and Chris Beeching via Jim Marshall ) . To be frank I never took the slightest interest in the amplifiers . I just liked him as an absolute gentleman . Terry was with him when he died . To be even more frank I never heard what he did well demonstrated . I have another friend who is involved with an amp called Lab 47 . Now that's an amp !!!!
Sorry if any errors , my Oz freind needs a lift to London and might miss his train . He tried to convince me to leave Hi Fi and join him in films and be a millionaire . No I will stay in the Church .
Not necessarily true. It could be measurement error or error cancellation or just a lucky measurement. It tells you nothing about what was not measured.nigel pearson said:
For example, I have in front of me a peer-reviewed paper(*) which claims to show how to run triodes with low distortion. The author measured second and third harmonics and showed that you can get a useful dip in distortion over a certain range of input voltages. Distortion is bad; therefore less distortion is good? What he fails to understand is that his measured distortion reduction (being due to grid current) is a matter of partial cancellation between two different curves. It also produces higher harmonics which will sound horrible, but he didn't measure them. His measurement is good, but his understanding is poor so he draws the wrong conclusion. That is why measurement is never enough; you also need a good theory. 'Sounds nice' is of course even worse than just a measurement.
(*) 'Low Distortion Operation of Some Miniature Dual Triodes', J Z Knapp, IRE Trans - Audio, July-August 1955, p125-132
DF 96 . I did use exactly that trick . I don't get the increased higher . Rightly or wrongly I believed what I read by Jean Hirage in translation of testing of listener preference . This was about 1980 . He said approximately that a high level of distortion which has harmonics that show something like an exponential curve getting lower as the harmonics increase may be thought to be zero distortion . Amplifiers with zero distortion will be classed the same . All others will be classified as colured and/or unpleasant . Talking recently with someone I was told that is simply because that curve is resonance of the ear . It has coping mechanisms for that distortion .
I was scared to listen to my amp because this cancellation seems too good to be true . I comforted myself by saying a feedback amplifier artificially does this .
I have listened to many good amplifiers and know my one is a good one . My motives for making it are not typical . To be honest valve amps interested me as much a cycling . I understand but don't want to . I did have to listen to my brother talk about them . It was love not interest . When I was told I will not make two the same I rejoiced and said I must have circumnavigated the problems . As said the more primitive it got the better it got . My goodness a resistor is a bit special as compered with a LED !
Amps are like Jigsaw puzzles . When they are right we see a complete picture . It is a picture we can repeat .
If someone says it could be this and it could be that I say buy some transistors .
I have nothing to prove here except how winning is about persisting with enough knowledge to get you through . This link below is about this . For once a true story that should be fantasy . He reminds me of me . He had know- how ( he was ridiculed , he won , certainly an engineer ) .
BBC Two - The World's Fastest Indian
I was scared to listen to my amp because this cancellation seems too good to be true . I comforted myself by saying a feedback amplifier artificially does this .
I have listened to many good amplifiers and know my one is a good one . My motives for making it are not typical . To be honest valve amps interested me as much a cycling . I understand but don't want to . I did have to listen to my brother talk about them . It was love not interest . When I was told I will not make two the same I rejoiced and said I must have circumnavigated the problems . As said the more primitive it got the better it got . My goodness a resistor is a bit special as compered with a LED !
Amps are like Jigsaw puzzles . When they are right we see a complete picture . It is a picture we can repeat .
If someone says it could be this and it could be that I say buy some transistors .
I have nothing to prove here except how winning is about persisting with enough knowledge to get you through . This link below is about this . For once a true story that should be fantasy . He reminds me of me . He had know- how ( he was ridiculed , he won , certainly an engineer ) .
BBC Two - The World's Fastest Indian
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Euphonic Distortion: Naughty but Nice? | Stereophile.com
I don't think Hiraga said euphonic at all ( the link ) . The suggestion was the right curve is zero . It might allow 1% as acceptable THD . The brain measures relative difference between harmonics and says it is correct . From what I know the ear produces about 30% harmonic distortion if pushed . The analogue side is crude . The digital side loosely speaking is used with the analogue ( little hairs ) . The more interesting thing is a feedback signal ( presumed ) that is a pulse . It comes back to the ear . Conjecture is a servo of sorts ( not me , Radcliffe Oxford ) . This might explain the sensitivity of us to so called timing information . US military I think I was told looked at hearing and found in some respects the shape of a wave was the question . It suggested 2 MHz bandwidth might be in someways detectable . Alas I can not find that data , I have read it in paper form . They were more interested in 5 Hz where it can kill .
I don't think Hiraga said euphonic at all ( the link ) . The suggestion was the right curve is zero . It might allow 1% as acceptable THD . The brain measures relative difference between harmonics and says it is correct . From what I know the ear produces about 30% harmonic distortion if pushed . The analogue side is crude . The digital side loosely speaking is used with the analogue ( little hairs ) . The more interesting thing is a feedback signal ( presumed ) that is a pulse . It comes back to the ear . Conjecture is a servo of sorts ( not me , Radcliffe Oxford ) . This might explain the sensitivity of us to so called timing information . US military I think I was told looked at hearing and found in some respects the shape of a wave was the question . It suggested 2 MHz bandwidth might be in someways detectable . Alas I can not find that data , I have read it in paper form . They were more interested in 5 Hz where it can kill .
Negative feeback does properly what cancellation does badly, except in the case of BJTs where Ebers-Moll can be relied on. That is why commercial/industrial electronics almost always uses feedback when it can, and other weaker tricks like predistortion only when feedback can't be used. Predistortion/cancellation also is more likely to result in low order distortion being lower in level than higher order, so it fails there too.
That was my attitude also . I think I now believe the oscilloscope . I did add loop feedback and got remarkable results . Bellow 1 watt the analyzer gave nothing until noise intruded when set to -70 dB . I have a hunch people don't work hard enough with pre-distortion . I spent perhaps 500 hours getting it right . No work was coming in so this passed the time . The route I took was as far from what anyone would expect as I think you could imagine . I didn't use a transistor although it would have been excellent . My friend might sell some so would be unhappy for me to say exactly how I did it .
Let me say this . If you get what looks like a feedback amp you didn't get what I did . Feedback or not it looked like a single triode albeit with 0.1% distortion at 1 watt . When too much feedback was used the second harmonic fell , third and fourth were equal ( ish ) and the rest tapered . Not bad . Not what I wanted . So many blind alleys I will tell you . The circuit is so simple , you would guess an afternoons work . Also I had many ideas that worked for 90% of test . There would always be one test that said forget this it is bad . I had to build a new oscillator as the modest intentions had been exceeded . I used NE5532 for that and had 50 kHz good enough to know what I was getting . If not it is pre distortion from the oscillator and skews the results . I had times when the output distortion was lower the the test gear if using my schools type lab oscillator . Now that tells you something .
Pre-distortion is the reality of life . Music is if you like distortion . How the amplifier reacts is not subtle .
I did use UL as it helped me get what I wanted . Now that was like enjoying a holiday in Blackpool for me . You know what I even played Bingo . Some Brits in Portugal were arrested for illegal Bingo . Now Portugal that's going to get you back on your feet intimidating tourists . I was a Bingo caller when young . We had a Vortexion amp and Grampian microphone . The former never made hi fi to sell in shops . Shame because they were superb . These were Showmen I worked for , honest and kind people who introduced me to real coffee (Kenco ) .
My friend Colleen told me how to say your name as she has a Russian client who is called the same . She is a carer ( nurse ) . Coleen is highly educated so an unusual lady to do this work . I mentioned about you . Colleen does not speak French , German , or Italian . Strange she should read any menu in those languages and translate . This "not speaking Italian " sounded fluent to me when in Sicily . Unlike me she is modest about her talents .
I saw in my mind a picture of an amplifier being a clock from your paper . One where the connection of the mechanism is poor . The pre distortion might be OK on synchronizing ? It sounds very good . Some say that feedback loops create harmonics higher up . DF 96 pointed out a simple idea . I measured and he was right , that concept is not easily proven to be correct . Best say it is false . Thus evidence of a poor clock is not strong for a feedback amp .However I will not give the idea up . Doubtless this has nothing to do with what you have been thinking ?
DF96 and earlier authors, are right so far as concerns observation of a rectangular signal from the generator which has been certainly located in two-dimensional space. However this case for a musical signal - a nonsense.
The straight line in 3d, for i(wt) for i looks differently, than in simple 2d space.
Therefore searches 0,000... the % of harmonicas, is the deadlock. Except the instrumental application, generators, oscilliscopes and so on.
The straight line in 3d, for i(wt) for i looks differently, than in simple 2d space.
Therefore searches 0,000... the % of harmonicas, is the deadlock. Except the instrumental application, generators, oscilliscopes and so on.
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I might respond to post 70 if I could understand it.
I don't recall saying anything about "rectangular signals" from a generator, or distortion figures with lots of 0's after the decimal point. Perhaps the OP has the same trouble understanding me as I have understanding him?
If we have yet another Fourier denier then it is not worth responding. I get bored talking to YAFDs on here.
I don't recall saying anything about "rectangular signals" from a generator, or distortion figures with lots of 0's after the decimal point. Perhaps the OP has the same trouble understanding me as I have understanding him?
If we have yet another Fourier denier then it is not worth responding. I get bored talking to YAFDs on here.
I don't much care if people swear as long as it isn't bullets aimed at me . Sometimes even that is OK . I do like courtesy and kindness . How can someone be all of those things and meet my criteria ? Well you can . The searing is the exception and is when ridiculously provoked . An understandable surprise in an impeccable human .
My mother would judge that person badly and would suggest if a friendship continued he or she change their ways .
This is how hi fi is . I have a 5 watts rule . Up to 5 watts proper hi fi ( DIN at worse ) . After that my amplifier can swear if it wants to . By then I feel like that also .
One of my amplifiers even at 150 watts has never said a bad word . It sounds about the same as the one that swears . Problem is the one that swears a bit also makes me cry with joy at times . Not because it is distorted , because it reminds me of when I was at a concert .
Sergey I get your extra dimension thing . Just don't know how to do the maths . To me it is how music causes it's own pre distortion which should matter . In a strange way SE tube amps are symmetrical . It is so difficult one either succeeds or fails . It is almost binary . My " priestly " amplifier is transistor and has twin VAS . It's symmetry is not a given quality . However it is symmetrical in the same way as the BMW motorcycle engine . The clock seldom stops running . The BMW has it's own problems and so does twin VAS ( secondary effects ) .
My main speakers are rather wonderful . They are big panels with very low distortion . If someone turns the bass up they stop being wonderful .The bass is almost better than real life becasue the microphone goes where I can't . Great for films and much better than the cinema . I doubt I could ever use them with a valve amplifier . Ones that would work are not as good as a transistor amp to my ears . That's where the priest comes in .
I will build the A2 211 amp . I have about a 20 % expectation it can work . The other took 500 hours , the A2 perhaps 2000 ? What I wont do is throw money at it . I will try by whatever means I don't know cathode feedback via the output in the style of PYE Mozart ( perhaps a winding is required like Quad ) . Perhaps the worst idea I ever had and if I had a grain of intelligence I wouldn't even say it . The idea is to drive my panels . I suspect a damping factor of 16 will do . I will have distortion in mind I can live with . It isn't euphonic . If it is , so is music . Zero distortion amps are euphonic if so . Any other distortion is horrible or fatiguing . The most common defect is a metallic quality ( 5 th + 7th ? ) . Guitar which you know to be acoustic might be a sampler as an example . The amplifier makes it difficult to say . Remember the sampler tries hard to be a guitar so we are not talking big effects . A CD player tries to be music in the same way .
My old Quad 303 is an excellent amplifier . I suspect it slightly converts music to MP3 as it's only defect ( notes fade into noise , they stop slightly before they get there , almost sounds better like that , very gentle ). Against the " best " amps in the world I expect it to win most of the time . Most people who owned one never had the speakers to know how good it is in battle . A gentleman and a solider !!! It won't put a Meyer to shame . Sonically it will shame plenty . If you look carefully on the analyzer it is a near zero distortion amp . You have to get it working to book spec before you do that . Then look again . The distortion that remains is Hiraga type . So - 80 dB ( 5 watt ) and fading . The criticisms made in the PDF I support . 99% of the time I don't listen that loud . Buy two and internally bridge them ? I think it should work . Bridge for current rather than voltage . Maybe use a fast transistor in the PSU . I can still get BDY 56 . Keep the output cap , it is a great protection device . On speakers that have real bass the cap is not a problem . I run a smaller cap to the tweeters . 99% of speakers do not have real bass , they double .
Quad Spot: Measuring distortion with software
My mother would judge that person badly and would suggest if a friendship continued he or she change their ways .
This is how hi fi is . I have a 5 watts rule . Up to 5 watts proper hi fi ( DIN at worse ) . After that my amplifier can swear if it wants to . By then I feel like that also .
One of my amplifiers even at 150 watts has never said a bad word . It sounds about the same as the one that swears . Problem is the one that swears a bit also makes me cry with joy at times . Not because it is distorted , because it reminds me of when I was at a concert .
Sergey I get your extra dimension thing . Just don't know how to do the maths . To me it is how music causes it's own pre distortion which should matter . In a strange way SE tube amps are symmetrical . It is so difficult one either succeeds or fails . It is almost binary . My " priestly " amplifier is transistor and has twin VAS . It's symmetry is not a given quality . However it is symmetrical in the same way as the BMW motorcycle engine . The clock seldom stops running . The BMW has it's own problems and so does twin VAS ( secondary effects ) .
My main speakers are rather wonderful . They are big panels with very low distortion . If someone turns the bass up they stop being wonderful .The bass is almost better than real life becasue the microphone goes where I can't . Great for films and much better than the cinema . I doubt I could ever use them with a valve amplifier . Ones that would work are not as good as a transistor amp to my ears . That's where the priest comes in .
I will build the A2 211 amp . I have about a 20 % expectation it can work . The other took 500 hours , the A2 perhaps 2000 ? What I wont do is throw money at it . I will try by whatever means I don't know cathode feedback via the output in the style of PYE Mozart ( perhaps a winding is required like Quad ) . Perhaps the worst idea I ever had and if I had a grain of intelligence I wouldn't even say it . The idea is to drive my panels . I suspect a damping factor of 16 will do . I will have distortion in mind I can live with . It isn't euphonic . If it is , so is music . Zero distortion amps are euphonic if so . Any other distortion is horrible or fatiguing . The most common defect is a metallic quality ( 5 th + 7th ? ) . Guitar which you know to be acoustic might be a sampler as an example . The amplifier makes it difficult to say . Remember the sampler tries hard to be a guitar so we are not talking big effects . A CD player tries to be music in the same way .
My old Quad 303 is an excellent amplifier . I suspect it slightly converts music to MP3 as it's only defect ( notes fade into noise , they stop slightly before they get there , almost sounds better like that , very gentle ). Against the " best " amps in the world I expect it to win most of the time . Most people who owned one never had the speakers to know how good it is in battle . A gentleman and a solider !!! It won't put a Meyer to shame . Sonically it will shame plenty . If you look carefully on the analyzer it is a near zero distortion amp . You have to get it working to book spec before you do that . Then look again . The distortion that remains is Hiraga type . So - 80 dB ( 5 watt ) and fading . The criticisms made in the PDF I support . 99% of the time I don't listen that loud . Buy two and internally bridge them ? I think it should work . Bridge for current rather than voltage . Maybe use a fast transistor in the PSU . I can still get BDY 56 . Keep the output cap , it is a great protection device . On speakers that have real bass the cap is not a problem . I run a smaller cap to the tweeters . 99% of speakers do not have real bass , they double .
Quad Spot: Measuring distortion with software
I agree and I know what I mean . There is a very small place where the signal seems reasonably symmetrical . A triangle wave is good to see it . Maybe it is what Sergey is saying ? As I said I do not have the maths for it . Bad hi fi is 2 D . Especially so on Quad ESL 63's . You see , what you hear from them has to happen in the chain . They are not the ones doing it . They can be so poor if wrongly feed .
It is binary. The trick is to get the amp to do it with typical valves . I got it in the end to do it with KT 88 and EL 34 to the point where it was almost identical . The big surprise was retesting the valves . The KT 88's were very different make to make . It might not be exactly symmetry . It is the sweet spot where the magic happens . It almost impossible to find . First thing is stop reading . It causes the correct answer to be lost . As Feynman says " First you have to define the problem " . If you use too many standard ideas what you will do is reinvent the wheel .
BTW the BH curve of the transformer comes into it . Far too long to discuss and I would need PHD help . Take it as the defect is in fact a nice thing . Like DC bias . Hate what it does to the bass . I said it before you had to . If there is a PHD in listening my daughter has it . She is Aspergers and was tested as an experiment in Oxford ( hearing of people like her ) . She has drastically better hearing than most . I supplied some of the test gear years ago . They use Hamsters rather than Mice because Hamsters are most like us in hearing . I source verified KEF T27's to do the work . The tests have to go above 40 kHz to be thought valid .
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Not too hot, not too cold, but just the right amount of 2nd for audio warmth. As this depends on the valve details and bias it is not surprising that it is different for each sample. I now understand what you mean by 'symmetrical': you mean just the right amount (for your ears) of asymmetry. Opposite meaning from that used by the rest of English speakers, but hey!
Stopping reading is more likely to cause the correct question to be lost.
I was rather sad that my friend John intends to build a Mullard circuit with the bits I gave him . He beamed and said he always wanted to . John has test gear probably above Audio Precision in ability to measure ? It won't be as easy to uses for audio work as that's not it's prime function . My guess is he can look at the sub - 140 dB range . He builds installments for measuring minute magnetic field variation .
Hey Ho . His face said it all . That's what he wants to do .
I will suggest injecting some 100 kHz to see if we can make the linearity improve . It is a push pull . Then take it out as in class D . It might work .
Reading too many books = Mullard . The statement " a poor thing but mine own " that I hold to be important .
Hey Ho . His face said it all . That's what he wants to do .
I will suggest injecting some 100 kHz to see if we can make the linearity improve . It is a push pull . Then take it out as in class D . It might work .
Reading too many books = Mullard . The statement " a poor thing but mine own " that I hold to be important .
DF 96 . Asymmetry almost symmetrical . Is all done by cheating I know . I did find the tripple cheat a bit special . That is both pre-distortion and loop feedabck + UL . With my transfomer 9.5 dB loop seemed splendid . 16.5 db was about the limit .
The point that seems most important is to get the valve centered with respect to bias . Then if two valves there are so many variations , more than that I dread to think . I did use transistor current sources and sinks until the end just to know how good it can be . I probably lost >6db of distortion reduction by not using them . My friend probably would have not listened to them if I had included them .
One thing I did find is running one valve about 80% above normal voltage was splendid . I read in it's notes the limiting voltage and used it . Reading carefully it was not clear it would be OK so I went to a more standard 320 V . Shame because it worked well . At home I would use it as it never gave trouble .
The point that seems most important is to get the valve centered with respect to bias . Then if two valves there are so many variations , more than that I dread to think . I did use transistor current sources and sinks until the end just to know how good it can be . I probably lost >6db of distortion reduction by not using them . My friend probably would have not listened to them if I had included them .
One thing I did find is running one valve about 80% above normal voltage was splendid . I read in it's notes the limiting voltage and used it . Reading carefully it was not clear it would be OK so I went to a more standard 320 V . Shame because it worked well . At home I would use it as it never gave trouble .
With a support on the already known.The crazy example of this was Galileo . I think the Church of Rome held Aristotle to be part of the Bible ? That saves about 10 hours of typing . The C of R believed that the heavens were perfect and Earth was corrupt because Aristotle said it . The Moon was less perfect because the " bad " Earth was corroding the Moon . Seems reasonably correct to me so far . When Galileo showed that the Moon had mountains like Earth he was in trouble . It made all the C of R was saying a lie to many . So sad for he who they represented to cause that . Take he as a philosopher if you prefer .
Galileo took the invention of two children which he improved . Venice had the best glass makers in the world . That gave him an advantage . His big crime was he was arrogant and disliked . I never met him so I am only saying what is remembered by others , the children in Holland ( ? ) also .
The point is a very simple idea can change everything . Also bringing in the respected scientists or philosophers sometimes takes us away from the truth . I love philosophy , I seldom regard it as the truth . I think Descartes said " I think , therefore I am " , to which I say " if I don't think , therefore I would not be " .
The truth usually is simple . When complexity arrives usually it is wrong . Chaos maths is useful as it defines things we can not easily know and why it happened . We can always design so as not to have the problem . When in an aircraft I am sure of that . Our Prime Minister announced an upgrading of the power of our Weather prediction computer . Give me strength . How many billion pounds for one extra day ? I can tell him for £1 000 000 what he ( we ) need to know for eternity . Compared with Northern Spain it will be rubbish . That area is said to have an ideal climate . It might continue to have it regardless if I am right . Buy your house 100 metres above sea level and have room to grow things . Have big dogs that are " usually " friendly and be happy .
Galileo took the invention of two children which he improved . Venice had the best glass makers in the world . That gave him an advantage . His big crime was he was arrogant and disliked . I never met him so I am only saying what is remembered by others , the children in Holland ( ? ) also .
The point is a very simple idea can change everything . Also bringing in the respected scientists or philosophers sometimes takes us away from the truth . I love philosophy , I seldom regard it as the truth . I think Descartes said " I think , therefore I am " , to which I say " if I don't think , therefore I would not be " .
The truth usually is simple . When complexity arrives usually it is wrong . Chaos maths is useful as it defines things we can not easily know and why it happened . We can always design so as not to have the problem . When in an aircraft I am sure of that . Our Prime Minister announced an upgrading of the power of our Weather prediction computer . Give me strength . How many billion pounds for one extra day ? I can tell him for £1 000 000 what he ( we ) need to know for eternity . Compared with Northern Spain it will be rubbish . That area is said to have an ideal climate . It might continue to have it regardless if I am right . Buy your house 100 metres above sea level and have room to grow things . Have big dogs that are " usually " friendly and be happy .
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