Andy, the 24v mod seemed to be not so simple, as I recall. Whether it was power supply to the op amp or current through the reference due to higher voltage, the issue was more than than voltage divider. Damn if I can recall! I do believe the issue was in overstressing something, though, getting too close to the edge.
I wouldn't
"Yes. I generally pre-load 3-pin's wherever I use them. I tend to use LM317/337 as pre-regulators and I prefer to use very low value resistors in the voltage divider setting the output voltage. This serves to "pre-load" these."
If you bypass the adjustment terminal with a capacitor to ground as the app notes advise for lower noise and much improved PSRR you will need a much bigger bypass cap. Biasing shunt voltage voltage references from the adjustment current works better with currents around a milliamp. The idea is to have a much lower impedance from the adjustment terminal to ground than from Vout to the adjustment terminal. Jung went from 120 ohms to 1K ohms in one of the articles on power supplies for the reasons above. I seem to remember some discussions on using a current source in this location. You really want to prebias you regulator at least 50 to 100 ma and that much current trough the reference to ground is not practical.
"In some experiments I found driving the PSU Pin's of Op-Amp's from the same type Op-Amp (which is a "Push-Pull Reg") with NO capacitance in the PSU line (this does take very TIGHT, three-dimensional layouting to work) sounded probably as good as Batteries with Filmcap only bypassing (Siemens naked chip stacked film MKT's)"
The rising output impedance of the regulator op amp with frequency ,combined with the decreasing PSRR of the op amp whose supply is being regulated make this real tricky. Throw a little lead inductance in and you have a real chance of instability at high frequencies and easily build an oscillator if using fast op amps. As Cuck Yeager said, " It can be done, but I don't recommend doing it."
"As an engineer, though not electronics, I sometimes find these threads overbearing. The original questions are often not addressed, and the arguments go on and on."
Don't read them then.......... If your requirement not that demanding, read the regulator data sheets and app notes and you will get enough knowledge for your application. If you can't swim stay out of the deep end of the pool. You would think people were paying 50 bucks an hour for a consultant after reading the bitching and whining. I don't know if you have heard but, they have these neat new things on WEB called search engines.........
http://www.analog.com/UploadedFiles/Application_Notes/135208865AN-202.pdf
http://www.analog.com/UploadedFiles/Technical_Articles/3752210Publication_V-Ref.pdf
http://www.onsemi.com/pub/Collateral/SR003AN-D.PDF
http://www.eetkorea.com/ARTICLES/2000NOV/2000NOV30_AMD_AN2.PDF
"Yes. I generally pre-load 3-pin's wherever I use them. I tend to use LM317/337 as pre-regulators and I prefer to use very low value resistors in the voltage divider setting the output voltage. This serves to "pre-load" these."
If you bypass the adjustment terminal with a capacitor to ground as the app notes advise for lower noise and much improved PSRR you will need a much bigger bypass cap. Biasing shunt voltage voltage references from the adjustment current works better with currents around a milliamp. The idea is to have a much lower impedance from the adjustment terminal to ground than from Vout to the adjustment terminal. Jung went from 120 ohms to 1K ohms in one of the articles on power supplies for the reasons above. I seem to remember some discussions on using a current source in this location. You really want to prebias you regulator at least 50 to 100 ma and that much current trough the reference to ground is not practical.
"In some experiments I found driving the PSU Pin's of Op-Amp's from the same type Op-Amp (which is a "Push-Pull Reg") with NO capacitance in the PSU line (this does take very TIGHT, three-dimensional layouting to work) sounded probably as good as Batteries with Filmcap only bypassing (Siemens naked chip stacked film MKT's)"
The rising output impedance of the regulator op amp with frequency ,combined with the decreasing PSRR of the op amp whose supply is being regulated make this real tricky. Throw a little lead inductance in and you have a real chance of instability at high frequencies and easily build an oscillator if using fast op amps. As Cuck Yeager said, " It can be done, but I don't recommend doing it."
"As an engineer, though not electronics, I sometimes find these threads overbearing. The original questions are often not addressed, and the arguments go on and on."
Don't read them then.......... If your requirement not that demanding, read the regulator data sheets and app notes and you will get enough knowledge for your application. If you can't swim stay out of the deep end of the pool. You would think people were paying 50 bucks an hour for a consultant after reading the bitching and whining. I don't know if you have heard but, they have these neat new things on WEB called search engines.........
http://www.analog.com/UploadedFiles/Application_Notes/135208865AN-202.pdf
http://www.analog.com/UploadedFiles/Technical_Articles/3752210Publication_V-Ref.pdf
http://www.onsemi.com/pub/Collateral/SR003AN-D.PDF
http://www.eetkorea.com/ARTICLES/2000NOV/2000NOV30_AMD_AN2.PDF
Re: I wouldn't
As an engineer, though not electronics, I sometimes find these threads overbearing. The original questions are often not addressed, and the arguments go on and on."
Don't read them then.......... If your requirement not that demanding, read the regulator data sheets and app notes and you will get enough knowledge for your application. If you can't swim stay out of the deep end of the pool. You would think people were paying 50 bucks an hour for a consultant after reading the bitching and whining.
-------------------------------------------------
Actually I charge a lot more than $400 for consultancy and made the point of not reading the rest of your post.
One of the forum rules is to be curtious, and your remarks fall far short of it.
Don't read my posts if you don't want to. Other stay polite.
As an engineer, though not electronics, I sometimes find these threads overbearing. The original questions are often not addressed, and the arguments go on and on."
Don't read them then.......... If your requirement not that demanding, read the regulator data sheets and app notes and you will get enough knowledge for your application. If you can't swim stay out of the deep end of the pool. You would think people were paying 50 bucks an hour for a consultant after reading the bitching and whining.
-------------------------------------------------
Actually I charge a lot more than $400 for consultancy and made the point of not reading the rest of your post.
One of the forum rules is to be curtious, and your remarks fall far short of it.
Don't read my posts if you don't want to. Other stay polite.
Thanks
Andy, Fred,
Thanks again. Andy, nice web site btw, and not too "overbearing" to read, either.
The numbers give me at least, a general reference for what it is people are trying to accomplish at the circuit level. I can judge the sound for myself (or not, as the case may be). The human ear has amazing powers of discrimination, unfortunately it is connected to a very unreliable receiver which suffers from an inherent lack of stability especially over time and temperature...
Peter
Andy, Fred,
Thanks again. Andy, nice web site btw, and not too "overbearing" to read, either.
The numbers give me at least, a general reference for what it is people are trying to accomplish at the circuit level. I can judge the sound for myself (or not, as the case may be). The human ear has amazing powers of discrimination, unfortunately it is connected to a very unreliable receiver which suffers from an inherent lack of stability especially over time and temperature...
Peter
Re: A couple of things
In audio the latter is critical and fundamental and also easy to get wrong, on first impressions. I also strongly encourage you all to think outside of conventional wisdom.
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I agree; I have learnt not to trust oft repeated wisdom in this which is a hobby. I have personally always listened and measured myself to confirm.
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The Jung reg's are old, but I've only heard one alternative that outperforms them at present. In all likelihood there's lots of alternatives, supported by my view that topology is often the least critical element, just correct implementation of that topology.
----------------------------------------------------
Have you heard some of the Japanese designs? Even in the 80s they had very purist designs accompanied by all the design equations and ocnsiderations published in amateur audio magazines?
I built some of these circuits and they still sound excellent - but you need to match semiconductors dynamically for dc stability, and you can only do that by having access to relatively large numbers of units.
In audio the latter is critical and fundamental and also easy to get wrong, on first impressions. I also strongly encourage you all to think outside of conventional wisdom.
----------------------------------------------------
I agree; I have learnt not to trust oft repeated wisdom in this which is a hobby. I have personally always listened and measured myself to confirm.
-----------------------------------------------------
The Jung reg's are old, but I've only heard one alternative that outperforms them at present. In all likelihood there's lots of alternatives, supported by my view that topology is often the least critical element, just correct implementation of that topology.
----------------------------------------------------
Have you heard some of the Japanese designs? Even in the 80s they had very purist designs accompanied by all the design equations and ocnsiderations published in amateur audio magazines?
I built some of these circuits and they still sound excellent - but you need to match semiconductors dynamically for dc stability, and you can only do that by having access to relatively large numbers of units.
You're right there - ears are great, brain gets in the way.
Part of the trick is to try and turn it off - over analysis always, in my experience, leads to flawed results.
This is where the 'tune' test and others really do work (ignoring the dogma of those promoting them). It's usually a method that is criticised by those whose systems don't do it
It gives a first-line fundamental analysis of whether the music is easy to follow. The rules of all styles of music seem to be hard wired into our brains, the ability to predict and follow the music is something that's easier when the clues are all there, in the right places, at the right time.
The other details come later.
Cue flames....
Andy.
P.S. the website was intended to be readable, yet informative, I hope I've succeeded. The only downside is the M$ -specific HTML that frontpage spews out. I'll dust off dreamweaver when I get a mo...
Koinichiwa,
Sadly, the reverse is true. In many ways, when considered in the context of transducers ears are horrible things. The actual mechnicas give rise to > 30% THD at around 94db SPL, within each individual octave only a very limited number of frequencies are actually percieved and relayed electrically to the brain and the "resolution" (the ear itself operates digital, not analogue) for each of these frequencies is surprisingly coarse.
So the ear as transducer is HORRIBLE BEYOND BELIEVE. If the Ear where a Microphone it would be utterly unusable even in a telephone.
Only the attachement to the Brain and it's prodigous real time analogue "DSP" capabilities make it possible to actually "hear" anything at all. This then of course also explains much of the differences in perception, as the ear/brain system has many learned responses, probably more of these than natural ones (my theory anyway).
So cultural differences influence what we hear as much as the actual training of the ear/brain system, there are some indications for genetic differences too.
Anyway, the brain as much "gets in the way" as it is "absolutely essential". It is the resolving of such dichotomies that makes audio so interesting, both from a technical and philosophical viewpoint.
Sayonara
ALW said:
Sadly, the reverse is true. In many ways, when considered in the context of transducers ears are horrible things. The actual mechnicas give rise to > 30% THD at around 94db SPL, within each individual octave only a very limited number of frequencies are actually percieved and relayed electrically to the brain and the "resolution" (the ear itself operates digital, not analogue) for each of these frequencies is surprisingly coarse.
So the ear as transducer is HORRIBLE BEYOND BELIEVE. If the Ear where a Microphone it would be utterly unusable even in a telephone.
Only the attachement to the Brain and it's prodigous real time analogue "DSP" capabilities make it possible to actually "hear" anything at all. This then of course also explains much of the differences in perception, as the ear/brain system has many learned responses, probably more of these than natural ones (my theory anyway).
So cultural differences influence what we hear as much as the actual training of the ear/brain system, there are some indications for genetic differences too.
Anyway, the brain as much "gets in the way" as it is "absolutely essential". It is the resolving of such dichotomies that makes audio so interesting, both from a technical and philosophical viewpoint.
Sayonara
Which is why a listening method that bypasses the technical issues and focusses on the emotional response is a more consistent assessment method. Especially as this is the sole reason I listen to music.
I get the feeling some people over-analyse things - if our ears were so flawed, we may as well not bother - fortunately this is not the case.
I've yet to see a definition and explanation of the science behind a humans emotional response to music.
It's something that does seem universal across cultures and ages. You can try to teach the details of quantum theory to a small child until you're blue in the face, but sit them in front of a piano and teach them 'Oranges and Lemons*' and it comes far more naturally.
Andy.
*Insert favourite childrens nursery rhyme / tune here.
Ears for Fears
"So the ear as transducer is HORRIBLE BEYOND BELIEVE. If the Ear where a Microphone it would be utterly unusable even in a telephone."
Yet it can detect sound pressure levels that move the ear drum the diameter of a hydrogen atom. The ear obviously can't be examined without considering the role of the brain in signal processing. We can usually recognize someone's voice over an extremely bandwidth and dynamically compressed telephone signal and pick out one conversation in the presence of several at a crowded party. Try that with DSP on a computer...... I don't think so.
I really think most people would agree that we can hear things we can measure as often we can measure things we can't hear.
Careful listening as a learned skill just as good engineering is. I will never understand why people seem to believe it has to be one or the other. Aren't there any engineers that can also hear? I feel perfectly comfortable using both skills but maybe that is because I am an engineer and my wife is a classical musician. I worked on a redesign conference bridge circuit a couple of years ago with a young lady who was a new engineer. She was very surpassed when the technicians reported to her how much better it sounded than the old circuit. No audiophile parts or design techniques were involved, just good solid engineering design. I never even listened to it during the design phase. Engineers that can't listen critically won't design the best audio equipment. Those who rely on listening only won't know how to get beyond a certain point without the technical skills. That's why people ask technical questions on the forum. If they could do it all by ear the wouldn't need to read any of this stuff.
Why is such a hard proposition for people to except? Keith Johnson is one of the sharpest engineers I've met but he also hears like a bat. I was there for part of a session recording the Dallas Wind Symphony. It was a very educational experience.
"So the ear as transducer is HORRIBLE BEYOND BELIEVE. If the Ear where a Microphone it would be utterly unusable even in a telephone."
Yet it can detect sound pressure levels that move the ear drum the diameter of a hydrogen atom. The ear obviously can't be examined without considering the role of the brain in signal processing. We can usually recognize someone's voice over an extremely bandwidth and dynamically compressed telephone signal and pick out one conversation in the presence of several at a crowded party. Try that with DSP on a computer...... I don't think so.
I really think most people would agree that we can hear things we can measure as often we can measure things we can't hear.
Careful listening as a learned skill just as good engineering is. I will never understand why people seem to believe it has to be one or the other. Aren't there any engineers that can also hear? I feel perfectly comfortable using both skills but maybe that is because I am an engineer and my wife is a classical musician. I worked on a redesign conference bridge circuit a couple of years ago with a young lady who was a new engineer. She was very surpassed when the technicians reported to her how much better it sounded than the old circuit. No audiophile parts or design techniques were involved, just good solid engineering design. I never even listened to it during the design phase. Engineers that can't listen critically won't design the best audio equipment. Those who rely on listening only won't know how to get beyond a certain point without the technical skills. That's why people ask technical questions on the forum. If they could do it all by ear the wouldn't need to read any of this stuff.
Why is such a hard proposition for people to except? Keith Johnson is one of the sharpest engineers I've met but he also hears like a bat. I was there for part of a session recording the Dallas Wind Symphony. It was a very educational experience.
Koinichiwa Weekes San,
I agree completely with your remarks. I generally reject "Numbers of Merit" figures (bandwidth, noise levels, output impedance etc.) as having a direct and repeatable link to percieved sound quality. And my observation with the older Jung Regs (pre AD797) where as I previously described them.
As to "if our ears are so flawed", if you look ONLY at the ears, yes, they ARE so flawed. As part of the Ear/Brain/Perception system they operate to give in the system with the other compents exceptional powers of discrimination and perception (some of which we still have problems repeating with mechanical/electronical/informational means), yet a large part of this is LEARNED response to stimuli.
Sayonara
ALW said:
I agree completely with your remarks. I generally reject "Numbers of Merit" figures (bandwidth, noise levels, output impedance etc.) as having a direct and repeatable link to percieved sound quality. And my observation with the older Jung Regs (pre AD797) where as I previously described them.
As to "if our ears are so flawed", if you look ONLY at the ears, yes, they ARE so flawed. As part of the Ear/Brain/Perception system they operate to give in the system with the other compents exceptional powers of discrimination and perception (some of which we still have problems repeating with mechanical/electronical/informational means), yet a large part of this is LEARNED response to stimuli.
Sayonara
Part of the trick is to try and turn it off - over analysis always, in my experience, leads to flawed results.
This is where the 'tune' test and others really do work (ignoring the dogma of those promoting them). It's usually a method that is criticised by those whose systems don't do it
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How is the first point consistent with your remarks about testing large no of circuits with power supplies. You can't just use the tune test and analysis, 'over' analysis must come in.
The tune test is a test of acceptability of music, not excellence. I have 3 systems that pass the test and have had many others that did but they differ in degree of goodness (analysis, timbre, accurracy, enjoyment, extention etc.).
The tune test is often used as an excuse to sell systems with some defects; it's a physcological technique to hide weaknesses and get the masses to agree on a tangential view of performance.
This is where the 'tune' test and others really do work (ignoring the dogma of those promoting them). It's usually a method that is criticised by those whose systems don't do it
------------------------------------------------------------
How is the first point consistent with your remarks about testing large no of circuits with power supplies. You can't just use the tune test and analysis, 'over' analysis must come in.
The tune test is a test of acceptability of music, not excellence. I have 3 systems that pass the test and have had many others that did but they differ in degree of goodness (analysis, timbre, accurracy, enjoyment, extention etc.).
The tune test is often used as an excuse to sell systems with some defects; it's a physcological technique to hide weaknesses and get the masses to agree on a tangential view of performance.
STILL LEARNING...
Hi,
Well...the Linn TT was definetely flawed, at least it could play a tune and could beat most contenders when set up correctly...
Something not even 9/10 Linn dealers could...
Nonetheless I'd rather have some gear playing a tune and be flawed tonally than having it the other way around.
Catch 33 I tell you...better brace yourself,
Hi,
Well...the Linn TT was definetely flawed, at least it could play a tune and could beat most contenders when set up correctly...
Something not even 9/10 Linn dealers could...
Nonetheless I'd rather have some gear playing a tune and be flawed tonally than having it the other way around.
Catch 33 I tell you...better brace yourself,
Re: STILL LEARNING...
Nonetheless I'd rather have some gear playing a tune and be flawed tonally than having it the other way around.
Catch 33 I tell you...better brace yourself, [/B][/QUOTE]
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Shouldn't this be regarded as a starting, and not end point? At last someone who says openely that the Linn is flawed. I have had two and they don't sound as good as the Lux PD300 and even a Garrard 301 which is one of the most tuneful I have. Needs to be sprung, not screwed to 20 kg of wood and lead which makes it more microphonic.
Whay is Catch 33?
Nonetheless I'd rather have some gear playing a tune and be flawed tonally than having it the other way around.
Catch 33 I tell you...better brace yourself,
[/B][/QUOTE]-----------------------------------------------------
Shouldn't this be regarded as a starting, and not end point? At last someone who says openely that the Linn is flawed. I have had two and they don't sound as good as the Lux PD300 and even a Garrard 301 which is one of the most tuneful I have. Needs to be sprung, not screwed to 20 kg of wood and lead which makes it more microphonic.
Whay is Catch 33?
I have to disagree here - many people focus on the wrong elements when listening to music at first - you only have to hear the tuneless bass that comes from many systems to realise many confuse quantity with quality.
The tune test reveals levels of difference readily - there's no sudden transition between tune / no tune, just degrees.
I know, I've made mistakes recently with some work I'm doing that measured better and initially sounded more impressive in HiFi terms (deeper bass, tighter control, better treble etc.). The measurements were all better too, but after time I found myself watching the TV.
The fundamental elements of music have to come first, but if you can add the hifi elements without degrading the music (and I know you can) then that's fine.
But none are essential to emotional involvement with music. Imaging ,soundstage, air, space etc etc are nothing on their own. It's easy to focus on these elements to the expense of music though.
Every genuine improvement (the ones that keep me up until the early hours in record-playing orgies) have fundamentally improved the tune, the pitch accuracy / and rythmic elements fundamental to music.
Some people do listen to different things, I have no problem with that, but if the system doesn't engage me in a way that encourages me to listen to music, at the expense of almost everything else, it won't do it for me. My music dominates my life, and I spend as much time listening as life will allow. So many people have systems that sit in the corner and are onyl used at parties etc. They listen to the same few recordings, because they're systems haven't opened up the world of music to them. My musical tastes have expanded exponentially with the imprvements to my system.
You may feel the tune test is flawed, but that seems partly based on your opinions of certain brands (I'm not keen on Linn electronics either) but it does work in a way that always leads me to the correct solutions.
But these sort of discussions never go anywhere here, so here's the challenge: -
Describe to me an unambigous system for the assessment of my system and I'll try it out. You need to be able to explain to me how to listen in the way you do.
I look forward to trying it.
Andy.
I think you misunderstand the tune method
The tune method has nothing to do with foot tapping.
The idea is to hum along to the tune (out loud or in your head). The system that makes it easier to follow (and this works really well with unfamiliar music where you have no pre-defined responses) is the best. It reveals MUCH more than many will give credit for, but at the end of the day, if you feel otherwise, that is your perogative - there's too many dogmatic discussions here.
You see it's clearly defined and obvious when the system is working correctly - the body movement often extends from it, simply because the ability to follow the music's twists and turns becomes so easy - you can be driven to join in, foot tapping, conducting, whatever - it's hard to stop.
So again over to you, tell me how to assess a system, and I'll try it. I am open minded, teach me!
Andy.
The tune method has nothing to do with foot tapping.
The idea is to hum along to the tune (out loud or in your head). The system that makes it easier to follow (and this works really well with unfamiliar music where you have no pre-defined responses) is the best. It reveals MUCH more than many will give credit for, but at the end of the day, if you feel otherwise, that is your perogative - there's too many dogmatic discussions here.
You see it's clearly defined and obvious when the system is working correctly - the body movement often extends from it, simply because the ability to follow the music's twists and turns becomes so easy - you can be driven to join in, foot tapping, conducting, whatever - it's hard to stop.
So again over to you, tell me how to assess a system, and I'll try it. I am open minded, teach me!
Andy.
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