Some folks can multi-task in this genre, teach, lecture, write and design amp(s) that pass the test of time.
Do it successfully over a really long time.
Others can't.
I can't.
Here in not so sunny California today (bit of needed rain), my medical treatment will be by a hands on academic clinician. We're truly blessed here.
As a personal aside, over the past fifteen years I have corresponded with dozens of people over the world about these amps.
Folks just quietly go on building it for their own pleasure.
There really was a time before this forum and the internet made it so much easier to share Prof. Leach's design.
I like Leach amps too........
Do it successfully over a really long time.
Others can't.
I can't.
Here in not so sunny California today (bit of needed rain), my medical treatment will be by a hands on academic clinician. We're truly blessed here.
As a personal aside, over the past fifteen years I have corresponded with dozens of people over the world about these amps.
Folks just quietly go on building it for their own pleasure.
There really was a time before this forum and the internet made it so much easier to share Prof. Leach's design.
I like Leach amps too........
Attachments
Hi Ace,
The internet certainly has certainly eliminated the tyranny of distance and disseminated views. Unfortunately it has a downside. In introducing people with similar views, it encourages navel -gazing one-eyeedness so visible on these fora.
Tony, I was designing original amplifiers commercially in 1974 - my first commercial products. Featuring the, new at the time, MJ15003/4 in CFT's unheard of then - with dethumped CCS Vas and degenerated diff'l front ends. Apart from the designs for others like the TAS golden ear award winning unrevolutionary Magnet 300F and folded cascode preamp in 1994, my Eidetic amplifiers of 1990 were 'giant killers' that , in a loaf of bread size, and a fraction of the price blew away the likes of ML, krell, Classe etc..
and some others later patented my topology despite copyright ( US patent office seems to not look too hard for prior art - to the great satisfaction of their applicants).
My new Simple Killer amp topology is truly revolutionary and a way audiophiles can have all the benefits of modern MOSFET technology and still be responsible to mother earth, our sustainer. Worth a professorship - bah. Probably be expected to hyphenate my name, put on airs, or teach people who really don't want to learn just want a piece of paper.
Cheers,
Greg
The internet certainly has certainly eliminated the tyranny of distance and disseminated views. Unfortunately it has a downside. In introducing people with similar views, it encourages navel -gazing one-eyeedness so visible on these fora.
Tony, I was designing original amplifiers commercially in 1974 - my first commercial products. Featuring the, new at the time, MJ15003/4 in CFT's unheard of then - with dethumped CCS Vas and degenerated diff'l front ends. Apart from the designs for others like the TAS golden ear award winning unrevolutionary Magnet 300F and folded cascode preamp in 1994, my Eidetic amplifiers of 1990 were 'giant killers' that , in a loaf of bread size, and a fraction of the price blew away the likes of ML, krell, Classe etc..
and some others later patented my topology despite copyright ( US patent office seems to not look too hard for prior art - to the great satisfaction of their applicants).
My new Simple Killer amp topology is truly revolutionary and a way audiophiles can have all the benefits of modern MOSFET technology and still be responsible to mother earth, our sustainer. Worth a professorship - bah. Probably be expected to hyphenate my name, put on airs, or teach people who really don't want to learn just want a piece of paper.
Cheers,
Greg
Evenin' Mr.amplifierguru,
"My new Simple Killer amp topology is truly revolutionary and a way audiophiles can have all the benefits of modern MOSFET technology and still be responsible to mother earth, our sustainer."
BTW, just how are sales going? You certainly plug yourself often and blatently enough on this thread.
Downside of the internet? Hmmmm. I'm pretty sure there are some really nasty folks out there using it to figure out how to slaughter other innocent folks over a simple difference in beliefs. Not so sure about your navel -gazing one-eyeedness or just what that might mean. I'm sure you're not criticizing people who wish to share information about amplifiers they like contrary to your beliefs? Surely not!! There's quite enough bad air out there already.
I like Leach too..........
"My new Simple Killer amp topology is truly revolutionary and a way audiophiles can have all the benefits of modern MOSFET technology and still be responsible to mother earth, our sustainer."
BTW, just how are sales going? You certainly plug yourself often and blatently enough on this thread.
Downside of the internet? Hmmmm. I'm pretty sure there are some really nasty folks out there using it to figure out how to slaughter other innocent folks over a simple difference in beliefs. Not so sure about your navel -gazing one-eyeedness or just what that might mean. I'm sure you're not criticizing people who wish to share information about amplifiers they like contrary to your beliefs? Surely not!! There's quite enough bad air out there already.
I like Leach too..........
Attachments
Greg,
just to remind you, this is diyaudio, and members are here to learn, and enjoy while doing it, not nescessarily please mother earth, but themselves!
here we build amps unlike commercial ones, no budgetary constraints, no time completion deadlines, parts and materials are according to what we want, not what others have decided for us and with a production run of only one unit! diye'rs take pride in their creations, it something that they can call "flesh and blood"
let no one take that fun away!
cheers!
just to remind you, this is diyaudio, and members are here to learn, and enjoy while doing it, not nescessarily please mother earth, but themselves!
here we build amps unlike commercial ones, no budgetary constraints, no time completion deadlines, parts and materials are according to what we want, not what others have decided for us and with a production run of only one unit! diye'rs take pride in their creations, it something that they can call "flesh and blood"
let no one take that fun away!
cheers!
Hi Ace,
I'd love to see some open-mindedness. But it's you that has a closed mind agenda. I try to investigate, improve, share information and you seem to try your damnedest to push a blinker agenda! Why is that? DIYers want to try, improve, learn.. not simply be directed into a 25 yo dated bipolar design as though it's a holy relic.
Cheers,
Greg
I'd love to see some open-mindedness. But it's you that has a closed mind agenda. I try to investigate, improve, share information and you seem to try your damnedest to push a blinker agenda! Why is that? DIYers want to try, improve, learn.. not simply be directed into a 25 yo dated bipolar design as though it's a holy relic.
Cheers,
Greg
Hi Tony,
Indeed. And I try my utmost to contribute to that ethos while encouraging forward thinking and technological benefits of modern devices/topologies.
The blinker agenda of not questioning a dated design is anathema to me.
Enjoy your 100 yo tubes - they certainly have a romantic 'sound' and place in audio history!
Cheers,
Greg
Indeed. And I try my utmost to contribute to that ethos while encouraging forward thinking and technological benefits of modern devices/topologies.
The blinker agenda of not questioning a dated design is anathema to me.
Enjoy your 100 yo tubes - they certainly have a romantic 'sound' and place in audio history!
Cheers,
Greg
Hi Tony,
re posts15&16.
the lower reference voltage reduces the LTP CE voltage. It is the cascode transistor that now has the very high CE voltage across it. This high cascode differential and low LTP differential voltage is a common method to allow low voltage, low noise input transistors to be used with higher voltage supply rails.
Back to my question:-
All,
re posts15&16.
the lower reference voltage reduces the LTP CE voltage. It is the cascode transistor that now has the very high CE voltage across it. This high cascode differential and low LTP differential voltage is a common method to allow low voltage, low noise input transistors to be used with higher voltage supply rails.
Back to my question:-
All,
What I like to know ( and I think this is more in line with topic )
is:
- If someone find we can improve Leach Amp - Input stage in any way?
- Solution more simple, without loss in performance?
- Solution more advanced with gained performance?
- How would this be practically carried out, in detail?
- What parameters in resulting amplifier performance would be better?
- How big a difference would this be, in figures?
- Would these differences improve the overall sound quality of amplifer?
#######################################
Some discussions lead nowhere.
There is not going to be anything gained from it.
Not regarding increasing of knowledge
and not for finding better practical solution to an issue.
There are constructive discussions and there are meaningless argumentations.
I would like to contribute to us being constructive.
Not all zeners are noisy
There is a widespread misunderstanding that zeners are always bad and LEDs are always good. That is a simple rule of thoumb, but it seems not true in all cases. May I remind you of the noise measurements I did:
http://www.diyaudio.com/forums/showthread.php?postid=417008#post417008
This study was limited and only applies to the particular brands of components I happened to test, but I suspect it captures a very important characteristic of zener diodes: the noise depends very much on the zener voltage. What I found (please have a look at the attached measurements in the link above) was that zener diodes are very noisy for zener voltages around 6 V, but the noise drops for lower and higher voltages. In fact, I found 12 V zeners to be as good as or even better than LEDs. A string of LEDs will add noise sources, and would result in higher noise than a single 12 V zener diode. LEDs are very good for voltages where you can use a single LED, or maybe 2 or 3 stringed together.
Edit: In the case of the Leach amp, also don't forget that the zeners are bypassed with capacitors to further reduce the noise.
This post is not to advocate using the zener solution instead of a ccs, I just want to point out some misunderstandings regarding zeners and noise.
There is a widespread misunderstanding that zeners are always bad and LEDs are always good. That is a simple rule of thoumb, but it seems not true in all cases. May I remind you of the noise measurements I did:
http://www.diyaudio.com/forums/showthread.php?postid=417008#post417008
This study was limited and only applies to the particular brands of components I happened to test, but I suspect it captures a very important characteristic of zener diodes: the noise depends very much on the zener voltage. What I found (please have a look at the attached measurements in the link above) was that zener diodes are very noisy for zener voltages around 6 V, but the noise drops for lower and higher voltages. In fact, I found 12 V zeners to be as good as or even better than LEDs. A string of LEDs will add noise sources, and would result in higher noise than a single 12 V zener diode. LEDs are very good for voltages where you can use a single LED, or maybe 2 or 3 stringed together.
Edit: In the case of the Leach amp, also don't forget that the zeners are bypassed with capacitors to further reduce the noise.
This post is not to advocate using the zener solution instead of a ccs, I just want to point out some misunderstandings regarding zeners and noise.
amplifierguru said:
The usual old and tiring war between academics and practiotioners, with people on both sides eagerly showing off their ignorance about the other side.
Of course most academics do not have all the practical experience of someone who has worked for decades in industy. However, just as obviously, the academics have gathered other types of knowledge during all those decades in academia. Whichever side you're on, assuming that those on the other side don't know anything that is useful and that you could learn from is plain stupid.
If I were to choose between
1. a well-reputed EE professor who once designed an amp according to theoretical guidelines and motivated all his design decisions without claiming to be musch smarter than everybody elss
and
2. someone who claims to have long industiral experience of designing amps but uses about half of his postings on the forum for no other purpose than to brag and boast about his own competence and tell us how stupid everybody else is
which one do you think I would consider the most credible?
amplifierguru said:
Having an academic and experienced clinician at home is even better.
You have lousy professors, and really good ones.
Mr Leach is one of the good ones, there is even a former student on this forum to vouch for that.
And, he is one who encourages his students to experiment, he even writes as such.
Someone with the academic mindset to learn and the eye for tricks of the trade hears both the professor and the practician.
I'm just smart enough to listen to Christer and Bob.
Well now, it is a holy relic.
Just how are sales going? Is this marketing idea of "brag and boast about" your "own competence and tell us how stupid everybody else"is, really working for you?
Seems I was wrong. You are "criticizing people who wish to share information about amplifiers they like contrary to your beliefs".
IMHO, you may keep your anathema. My Leach amp causes you no harm and your railing against it does not nor will it ever change my opinion. I am not pushing a blinkered agenda. Only shareing my delight with this marvelous sounding amplifier.
Are you advocating on this forum, that members should shut up and adopt only your opinions? Now that would be narrow minded and blinkered.
Shakespeare, Hamlet
"The lady doth protest too much, methinks." seems to apply here.
Poor Mr. john-china asks a simple non threatening question and it degenerates into this old saw again.
Maybe it's time to get back on subject and try to give him a good answer. I resign. Got better things to do. Build another Leach SuperAmp.
Just how are sales going? Is this marketing idea of "brag and boast about" your "own competence and tell us how stupid everybody else"is, really working for you?
Seems I was wrong. You are "criticizing people who wish to share information about amplifiers they like contrary to your beliefs".
IMHO, you may keep your anathema. My Leach amp causes you no harm and your railing against it does not nor will it ever change my opinion. I am not pushing a blinkered agenda. Only shareing my delight with this marvelous sounding amplifier.
Are you advocating on this forum, that members should shut up and adopt only your opinions? Now that would be narrow minded and blinkered.
Shakespeare, Hamlet
"The lady doth protest too much, methinks." seems to apply here.
Poor Mr. john-china asks a simple non threatening question and it degenerates into this old saw again.
Maybe it's time to get back on subject and try to give him a good answer. I resign. Got better things to do. Build another Leach SuperAmp.
Hi Ace,
I am not railing against it at all. Nor am I calling it a holy relic - just the way you obsess over it. How many have you built? How many others? What's the best amplifier?
To investigate variations on the front end, which you are wanting to do, I think you need to start with good 2BJT CCS's off the supply rails to provide both the cascode bias and the tail supply. Then you don't need to use zeners at all, and PSRR will be high without the supply line RC's. I did a comparison of the two front ends for interest -
http://www.diyaudio.com/forums/showthread.php?postid=790678#post790678
Crister,
My amp design is worth crowing about because it addresses real audio issues simply and elegantly and at low cost, helping to bring quality audio to more people. Today's technology today! I'm terribly sorry if I make you feel stoopid, I'll be more genteel. The downside of not being on a state wage is that I need to promote my creations.
It was not I who made dubious claims for design decisions.
Cheers,
Greg
I am not railing against it at all. Nor am I calling it a holy relic - just the way you obsess over it. How many have you built? How many others? What's the best amplifier?
To investigate variations on the front end, which you are wanting to do, I think you need to start with good 2BJT CCS's off the supply rails to provide both the cascode bias and the tail supply. Then you don't need to use zeners at all, and PSRR will be high without the supply line RC's. I did a comparison of the two front ends for interest -
http://www.diyaudio.com/forums/showthread.php?postid=790678#post790678
Crister,
My amp design is worth crowing about because it addresses real audio issues simply and elegantly and at low cost, helping to bring quality audio to more people. Today's technology today! I'm terribly sorry if I make you feel stoopid, I'll be more genteel. The downside of not being on a state wage is that I need to promote my creations.
It was not I who made dubious claims for design decisions.
Cheers,
Greg
Greg,
Please contain yourself. Christer is one very smart guy, with considerable academic and practical achievements which he does not crow about. He is also a very tactful and generous human being....
I am more than willing to say your SKA design is clever and innovative. But neither is it perfect; none of them are. You have a powerful analytical ability and good designs behind you, no question; but your immodesty and attacks on others detract from your credibility. Your failure to give the subjectivists the time of day does you further discredit, and your obvious contempt for the tinkerers, the amateurs who created some of the world's best amps, is a shame. If anyone here thinks they are smart, have a gander at Shinichi-Kamijo, who I think is a genius:
Kamijo
Some posts back you made a very telling comment. You communicated your dripping contempt for amps which distort so badly they are '...musical instruments'. This made me laugh out loud. A good amp is a musical instrument; it's an extension of the musical instruments which make music!! Why should we not lavish the same subjective and quirky care in the design of this part of the recording chain? Is it not simply pragmatic to gainfully exploit the artefacts inevitably produced rather than suffer the chemo of zero distortion and the ray treatment of GNFB? The best we can hope for is to remove most of the H5 and beyond; if a bit of H2 and H3 is left over but nothing else, what do we have? I would opine that we have almost the distortion profile of a vacuum tube.......
Progress in most technologies depends on unreasonable men - those who think outside the square. You, Greg, can think outside the square, but meter reading and distortion analysis is very difficult to correlate with a better sounding amp, perhaps because the consumer base is very subjective in its assessments. There is a valid argument for designing amps from both the objective and the subjective standpoint, and if you have ever heard a Cary amp you will recognise the phrase 'house sound'.
That said, there are sufficient anomalies in audio subjectivism to graciously accommodate most camps. SE triodes sound great on simpler music like jazz and acoustic; SS sounds marvellous, when properly done, on full scale orchestral music and rock. But no one amp seems suitable for the entire repertoire, and there's the rub........
Cheers,
Hugh
Please contain yourself. Christer is one very smart guy, with considerable academic and practical achievements which he does not crow about. He is also a very tactful and generous human being....
I am more than willing to say your SKA design is clever and innovative. But neither is it perfect; none of them are. You have a powerful analytical ability and good designs behind you, no question; but your immodesty and attacks on others detract from your credibility. Your failure to give the subjectivists the time of day does you further discredit, and your obvious contempt for the tinkerers, the amateurs who created some of the world's best amps, is a shame. If anyone here thinks they are smart, have a gander at Shinichi-Kamijo, who I think is a genius:
Kamijo
Some posts back you made a very telling comment. You communicated your dripping contempt for amps which distort so badly they are '...musical instruments'. This made me laugh out loud. A good amp is a musical instrument; it's an extension of the musical instruments which make music!! Why should we not lavish the same subjective and quirky care in the design of this part of the recording chain? Is it not simply pragmatic to gainfully exploit the artefacts inevitably produced rather than suffer the chemo of zero distortion and the ray treatment of GNFB? The best we can hope for is to remove most of the H5 and beyond; if a bit of H2 and H3 is left over but nothing else, what do we have? I would opine that we have almost the distortion profile of a vacuum tube.......
Progress in most technologies depends on unreasonable men - those who think outside the square. You, Greg, can think outside the square, but meter reading and distortion analysis is very difficult to correlate with a better sounding amp, perhaps because the consumer base is very subjective in its assessments. There is a valid argument for designing amps from both the objective and the subjective standpoint, and if you have ever heard a Cary amp you will recognise the phrase 'house sound'.
That said, there are sufficient anomalies in audio subjectivism to graciously accommodate most camps. SE triodes sound great on simpler music like jazz and acoustic; SS sounds marvellous, when properly done, on full scale orchestral music and rock. But no one amp seems suitable for the entire repertoire, and there's the rub........
Cheers,
Hugh
aksa
"
Greg,
Please contain yourself. Christer is one very smart guy, with considerable academic and practical achievements which he does not crow about. He is also a very tactful and generous human being....
I am more than willing to say your SKA design is clever and innovative. But neither is it perfect; none of them are. You have a powerful analytical ability and good designs behind you, no question; but your immodesty and attacks on others detract from your credibility. Your failure to give the subjectivists the time of day does you further discredit, and your obvious contempt for the tinkerers, the amateurs who created some of the world's best amps, is a shame. If anyone here thinks they are smart, have a gander at Shinichi-Kamijo, who I think is a genius:
"
escuse mr Dean but i dont see anything wrong with our guru
i think he is kind old chap, i am sure christer is a nice person too
i think youre overreacting a little bit
"
Greg,
Please contain yourself. Christer is one very smart guy, with considerable academic and practical achievements which he does not crow about. He is also a very tactful and generous human being....
I am more than willing to say your SKA design is clever and innovative. But neither is it perfect; none of them are. You have a powerful analytical ability and good designs behind you, no question; but your immodesty and attacks on others detract from your credibility. Your failure to give the subjectivists the time of day does you further discredit, and your obvious contempt for the tinkerers, the amateurs who created some of the world's best amps, is a shame. If anyone here thinks they are smart, have a gander at Shinichi-Kamijo, who I think is a genius:
"
escuse mr Dean but i dont see anything wrong with our guru
i think he is kind old chap, i am sure christer is a nice person too
i think youre overreacting a little bit
No, Mastertech,
I don't believe so. Two points:
1. I post infrequently, so I try to respond to the tone of the thread rather than just one post, and
2. Greg apologised to Christer for making him feel 'stoopid'. This is unacceptable in writing, particularly when the worst possible interpretation is inevitably communicated by the very nature of an internet forum.
In any event, my comments could have been much stronger. I like and admire Greg too, but I feel that he should rein in his comments.
Cheers,
Hugh
I don't believe so. Two points:
1. I post infrequently, so I try to respond to the tone of the thread rather than just one post, and
2. Greg apologised to Christer for making him feel 'stoopid'. This is unacceptable in writing, particularly when the worst possible interpretation is inevitably communicated by the very nature of an internet forum.
In any event, my comments could have been much stronger. I like and admire Greg too, but I feel that he should rein in his comments.
Cheers,
Hugh
Hi Hugh.
Hi Mastertech.
I have attempted to answer John-china's Q's scientifically for which I have been shouted down by others, plus an attempted character assassination for daring to question this design, by those who it seems have built nothing else.
For every subjective assessment an equal and opposite one will be forthcoming, if the sample is large enough. Measurement defines progress, as long as we measure the correct things.
I appreciate your comments. I like to keep an open mind.
Cheers,
Greg
Hi Mastertech.
I have attempted to answer John-china's Q's scientifically for which I have been shouted down by others, plus an attempted character assassination for daring to question this design, by those who it seems have built nothing else.
For every subjective assessment an equal and opposite one will be forthcoming, if the sample is large enough. Measurement defines progress, as long as we measure the correct things.
I appreciate your comments. I like to keep an open mind.
Cheers,
Greg
HI Greg,
Thank you for your post. I should add that I do not attack you for commenting on the Leach amp. I too can see areas I would do quite differently.
Absolutely. Agree 100%. This means that you have to choose a particular 'sound', and run with it. Your choice might be commercial, it might not. With your experience, I'd suggest the former.
And to make it a commercial success, the answer is marketing. We have so many examples of this, not all good, to consider!
Cheers,
Hugh
Thank you for your post. I should add that I do not attack you for commenting on the Leach amp. I too can see areas I would do quite differently.
Absolutely. Agree 100%. This means that you have to choose a particular 'sound', and run with it. Your choice might be commercial, it might not. With your experience, I'd suggest the former.
And to make it a commercial success, the answer is marketing. We have so many examples of this, not all good, to consider!
Cheers,
Hugh
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