Re: Re: Re: opamps
Those who need settle down on facts are free to do that. Those who look for different approaches, should be equally free in their pursuit. I don't see any reason to describe anything as " magic gold pens". We shouldn' t be bound by any predetermined recipes and solutions in our quest for better audio. IMO, this is the only way to make a real progress in all aspects of true audio.
millwood said:
Those who need settle down on facts are free to do that. Those who look for different approaches, should be equally free in their pursuit. I don't see any reason to describe anything as " magic gold pens". We shouldn' t be bound by any predetermined recipes and solutions in our quest for better audio. IMO, this is the only way to make a real progress in all aspects of true audio.
Don't get me wrong. Geers and artsies are both my target here. The rigidity of the stances is why neither camp learns anything from the other. And no-one gets to the why of it all.
Of course, in practice, only I can answer that question for myself. I have to learn how to listen the best I can and also learn the science that goes behind the effects that I hear.
So now, I'll ask for "opinions" on this...
Why would TI label the OPA2134 and OPA2227 as suitable for pro audio applications if they were not suitable as replacements (or upgrades) to the NE5532? These all have similar distortion ratings, so what is causing the differences and why? Slew rate? Settling time? The OPA627 is at least twice as "clean" as the the others. What am I getting for that extra precision?
ensen.
Of course, in practice, only I can answer that question for myself. I have to learn how to listen the best I can and also learn the science that goes behind the effects that I hear.
So now, I'll ask for "opinions" on this...
Why would TI label the OPA2134 and OPA2227 as suitable for pro audio applications if they were not suitable as replacements (or upgrades) to the NE5532? These all have similar distortion ratings, so what is causing the differences and why? Slew rate? Settling time? The OPA627 is at least twice as "clean" as the the others. What am I getting for that extra precision?
ensen.Why would TI label the OPA2134 and OPA2227 as suitable for pro audio applications if they were not suitable as replacements (or upgrades) to the NE5532? These all have similar distortion ratings, so what is causing the differences and why? Slew rate? Settling time? The OPA627 is at least twice as "clean" as the the others. What am I getting for that extra precision?
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Who says the 2134 is not suitable for replacing the 5532? Why not? I don't know the 2227 too well.
Why is the 627 twice as clean as the others? In what respect?
Fact is, they are all high open loop gain, lower bandwidth devices. The 627 is costly partly due to the low offset. None of them drive cables as well as some of the AD opamps.
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Who says the 2134 is not suitable for replacing the 5532? Why not? I don't know the 2227 too well.
Why is the 627 twice as clean as the others? In what respect?
Fact is, they are all high open loop gain, lower bandwidth devices. The 627 is costly partly due to the low offset. None of them drive cables as well as some of the AD opamps.
fmak said:
My mistake... I got the impression that several members think the 5532 is a better opamp than the others.
As for "clean" devices, the 627 (.00003%) has THD+N ratings about 1/2 of both the 2134 (.00008%) and 2227 (.00005%). I couldn't find THD+N specs for the 5532. The noise (nV/Hz^.5) measures close for all four opamps including the 5532.
Since the 5532 is the cheapest of them all, it may still present the best value. I'm still trying to figure this out and haven't yet downloaded the AD datasheets or decided which ones to get samples of. I may end up trying 8 different ICs just to find out.
ensen.
I still think that he is joking.......
Price has nothing to do with it. They can gold plate a LM833 and it would still suck.
Just ask anyone who made the mistake of using one.
Yeah, it is better than a TL072. But outside of '741, what isn't?
You can measure all you want, but if it sounds like crap, it doesn't matter to me how good it measures, or what it costs. Performance is the bottom line, and the '833 doesn't cut it, bub.
I don't want to have to 'splain this again.
Jocko
Price has nothing to do with it. They can gold plate a LM833 and it would still suck.
Just ask anyone who made the mistake of using one.
Yeah, it is better than a TL072. But outside of '741, what isn't?
You can measure all you want, but if it sounds like crap, it doesn't matter to me how good it measures, or what it costs. Performance is the bottom line, and the '833 doesn't cut it, bub.
I don't want to have to 'splain this again.
Jocko
PMA>”In case of suspicion of high frequency oscillations - try to put transistor radio near the amp and check (both AM and FM) for whistles. Hum or buzz might be standard as a product of power supply diodes turn-off.”
Oh yes this is one trick I have used for Decades scan across the FM band first and listen for Dead air and or dead Air with an AC hum. On AM do the same thing. And last but not least AM is great at selecting quiet Rectifier diodes.
Bmcevers> “ 2. Noise Figure, this is almost as important as slew rate. The amp should have a low 1/f frequency to ensure that noise doesn't increase in the lowest audible octaves. Low noise opamps should have a noise figure under 10nV/sq.rt Freq. The NE5532/NE5534 excel at low noise applications(4.5nV/sq.rt Freq) especially when driven from a low impedence source (like the output of another opamp). NE5532 also has excellent common mode characteristics which allow them to drive unbalanced input/feedback impedences with amazingly low levels of THD, 99% of opamps CANNOT do this. The OPA627 is an amazing all around performer (albeit costly). It uses difet inputs (low offset, high input impedence) but DOES NOT have as excellent common-mode qualities of the NE5532. The OPA627's will only beat the NE5532 (objectively, not subjectively) when the source impedence exceeds 10kOHMS.
Noise lower than 15 nV/sq.rt are not needed in line level stages since the Impedances around the Input like the Volume control are most often quite High > than 50K Otherwise a most excellent treatment of op amp issues. And yes the OPA-627 is quite user friendly being unity gain stable and a gain/Phase margin of about 70 dB helps for stability in less than ideal layouts.
Purplepeople> “tend to scale down the published specs since most are taken with signal at the inverting input. It may be possible to put two inverting stages together, but I do not know if that is cleaner than just using one stage non-inverting.”
Very true see data sheet application section of the AD-8610 for info on the Differences between the 8610 and OPA-627 in both inverting and non inverting mode.
cdl>”Have you ever considered that there might be parameters yet to be discovered, that present distortion analysers are not so good at measuring?
There might be room for evolution in distortion analysis... especially considering that almost all new audio thingies measure acceptably in terms of SNR, THD etc.; but definately do not all sound nice!”
You hit the hammer on the Head IMHO. I believe that the subjective differences in Audio equipment and the Component parts that go into them do have their own unique sound and this also includes active devices of apparently similar performance.
Some op amps that I like a lot for line level stages and are easy for the user to implement without hassles are AD-8610, AD-8620 (Dual) AD-8065, AD-8066 AD-825, OPA-627, LT-1122, For higher gain Line level stages > that 20 dB is the HA-5160 BTW has comp pin useable as output to Buffer but lower current at that pin than the AD-744 and similar AD op amps
Oh yes this is one trick I have used for Decades scan across the FM band first and listen for Dead air and or dead Air with an AC hum. On AM do the same thing. And last but not least AM is great at selecting quiet Rectifier diodes.
Bmcevers> “ 2. Noise Figure, this is almost as important as slew rate. The amp should have a low 1/f frequency to ensure that noise doesn't increase in the lowest audible octaves. Low noise opamps should have a noise figure under 10nV/sq.rt Freq. The NE5532/NE5534 excel at low noise applications(4.5nV/sq.rt Freq) especially when driven from a low impedence source (like the output of another opamp). NE5532 also has excellent common mode characteristics which allow them to drive unbalanced input/feedback impedences with amazingly low levels of THD, 99% of opamps CANNOT do this. The OPA627 is an amazing all around performer (albeit costly). It uses difet inputs (low offset, high input impedence) but DOES NOT have as excellent common-mode qualities of the NE5532. The OPA627's will only beat the NE5532 (objectively, not subjectively) when the source impedence exceeds 10kOHMS.
Noise lower than 15 nV/sq.rt are not needed in line level stages since the Impedances around the Input like the Volume control are most often quite High > than 50K Otherwise a most excellent treatment of op amp issues. And yes the OPA-627 is quite user friendly being unity gain stable and a gain/Phase margin of about 70 dB helps for stability in less than ideal layouts.
Purplepeople> “tend to scale down the published specs since most are taken with signal at the inverting input. It may be possible to put two inverting stages together, but I do not know if that is cleaner than just using one stage non-inverting.”
Very true see data sheet application section of the AD-8610 for info on the Differences between the 8610 and OPA-627 in both inverting and non inverting mode.
cdl>”Have you ever considered that there might be parameters yet to be discovered, that present distortion analysers are not so good at measuring?
There might be room for evolution in distortion analysis... especially considering that almost all new audio thingies measure acceptably in terms of SNR, THD etc.; but definately do not all sound nice!”
You hit the hammer on the Head IMHO. I believe that the subjective differences in Audio equipment and the Component parts that go into them do have their own unique sound and this also includes active devices of apparently similar performance.
Some op amps that I like a lot for line level stages and are easy for the user to implement without hassles are AD-8610, AD-8620 (Dual) AD-8065, AD-8066 AD-825, OPA-627, LT-1122, For higher gain Line level stages > that 20 dB is the HA-5160 BTW has comp pin useable as output to Buffer but lower current at that pin than the AD-744 and similar AD op amps
opamps
Millwood,
It sounds like you and I are on the same page. And, Yes, you did read me 100% correct.
My problem with subjectivity is what you hear in a piece of audio equipment and what I or any of the other 6 billion people on this earth hear probably, no MOST DEFINITELY, WILL NOT CORRELATE TO ANY DEGREE. If there are unmeasurable, undefinable sound characteristics out there yet to be discovered, I'll be amazed.
I think any almost any real (read: objective, measurable) sound "anomalies" can be explained by:
1. Frequency Response.
2. Phase of signal with respect to frequency.
3. All forms of THD.
Why would a whole community of hobbyists embrace a philosophy (subjectivism) were so few concur with each other. The fact that so many people disagree should be proof enough that something is not right, somebody has vomited in the petunias, there is a real problem with the concept. I feel that a lot of armchair engineers out here have mistaken "the art of audio electronics" the wrong way. Yes it is an art in it's eloquence, complexity, and yes SOMETIMES simplicity of certain circuit topologies to tackle the task it was designed to do, but the "scientific method" is NEVER to be left out of this process. If you want to bring "art" in it's classical sense to your design, save it for the solid 24 carat gold chassis your going to mount your competently designed circuit into. It's taken over 100 years of scientific research and development to get audio equipment to point where it's at today. If you doubt the scientific methods used in the evolution of audio electronics, and you endorse antiquated equipment from the "Golden Years", go down to your local antique store (or maybe someone you know) and listen to a "Victrola" phonograph, that should give you a little dose of reality. Think of all the myths and legends from almost any culture from around the world (the earth is flat, etc. etc.), although they may endured for many hundreds of years, modern society now laughs and mocks at their ignorance. I think 100 years from now subjectivity will have fallen into that category. Again I do not mean to offend, I just feel it needs to be said,
Sincerely,
Brannon
Millwood,
It sounds like you and I are on the same page. And, Yes, you did read me 100% correct.
My problem with subjectivity is what you hear in a piece of audio equipment and what I or any of the other 6 billion people on this earth hear probably, no MOST DEFINITELY, WILL NOT CORRELATE TO ANY DEGREE. If there are unmeasurable, undefinable sound characteristics out there yet to be discovered, I'll be amazed.
I think any almost any real (read: objective, measurable) sound "anomalies" can be explained by:
1. Frequency Response.
2. Phase of signal with respect to frequency.
3. All forms of THD.
Why would a whole community of hobbyists embrace a philosophy (subjectivism) were so few concur with each other. The fact that so many people disagree should be proof enough that something is not right, somebody has vomited in the petunias, there is a real problem with the concept. I feel that a lot of armchair engineers out here have mistaken "the art of audio electronics" the wrong way. Yes it is an art in it's eloquence, complexity, and yes SOMETIMES simplicity of certain circuit topologies to tackle the task it was designed to do, but the "scientific method" is NEVER to be left out of this process. If you want to bring "art" in it's classical sense to your design, save it for the solid 24 carat gold chassis your going to mount your competently designed circuit into. It's taken over 100 years of scientific research and development to get audio equipment to point where it's at today. If you doubt the scientific methods used in the evolution of audio electronics, and you endorse antiquated equipment from the "Golden Years", go down to your local antique store (or maybe someone you know) and listen to a "Victrola" phonograph, that should give you a little dose of reality. Think of all the myths and legends from almost any culture from around the world (the earth is flat, etc. etc.), although they may endured for many hundreds of years, modern society now laughs and mocks at their ignorance. I think 100 years from now subjectivity will have fallen into that category. Again I do not mean to offend, I just feel it needs to be said,
Sincerely,
Brannon
Re: I still think that he is joking.......
i dont know whats wrong with lm833 (never used it) but most of the time if the specs are ok then it sound ok too .
sometimes i read posts like "this op amp got a lack of bass"
if the freq responce is flat then HOW can there be a lack of bass ??? some of u are trying to tell the differences between amps , so u say things like the bass is too boomy , lack of bass etc etc....
if its true then those are poorly designed circuits
i understand people that say those speakers lack bass , but op amps or amps ????
Jocko Homo said:
i dont know whats wrong with lm833 (never used it) but most of the time if the specs are ok then it sound ok too .
sometimes i read posts like "this op amp got a lack of bass"
if the freq responce is flat then HOW can there be a lack of bass ??? some of u are trying to tell the differences between amps , so u say things like the bass is too boomy , lack of bass etc etc....
if its true then those are poorly designed circuits
i understand people that say those speakers lack bass , but op amps or amps ????
Again I would like to assert that I really don't mean to offend, it's just that I find remarks like Jocko's extremely humorous. I've had an extremely rough day and the laugh I had after I read that took all my anxiety away. Thank-You!!
I guess the bottom line with subjectivism is this. When I was growing up, my family wasn't rich. My parents couldn't afford to buy me the $10K Mark-Levinson amp (a cheap one) I listened to when I would make my weekly trips into LA to the high-end audio salons (I would bug the hell out of the snooty sales people too). I was the kid that would drool all over the articles from my latest issue of Audio Magazine (as many of you here probably did) and dream of someday owning equipment like that. As you get older, graduate from college and enter the workforce, the reality of your life sets in and you conclude and accept that you will be of retirement age when you might actually be able to acquire such equipment. The reason is that you've become aware that shelter, transportation and food take precedence over "a hobby". Such are the cruel realities of life.
Because I am older and must work hard for what I have (and being a technical minded individual), I get a little irate when I see advertisements for "subjectivist" items like:
"$500 24ct gold-plated mains power cables designed for the demanding audio enthusiast"
As if the last six feet of cable is going to make up for the 10000ft of "generic" cable your electrical utility company ran from the generation plant to your house.
It's this kind of snobby, pricey, unobtanium, elitest, snake oil, black magic, wizardry that I detest. I must have equipment (or design equipment) that is true, clinical, analytical, adds no coloration of it's own, the proverbial "straight wire with gain". And if you can't justify a components cost with it's measurable performance, then it's spec sheet isn't worth the paper it's printed on. I do believe that there are high end audio components out there that do deserve to fetch the high sums of money they sell for, because they look and are constructed as good as they sound. But there seem to be a myriad of companies out there trying to sell their idea of "Audio Euphoria" complete with 20kHZ THD in the 3-5% range, for an unbelievable amount of cash. They say a fool and his money are easily separated, and this fool works to hard to let it go that easy.
I also feel it's poor policy for senior members of this forum to recommend AD825 to people that have little experience in this field, you are doing them a great disservice. Most people on this forum I think will agree with me on this if they think about it. If you go to the AD site, it's stated right there in the description of recommended uses for this IC, it was intended for "video and portable instrumentation" there is not one mention of it's use in audio equipment, being the company that designed the IC, wouldn't AD make a claim for audio if it could? I am not saying it CAN'T be used in an audio environnment (I would say it's far from an ideal candidate though) and with careful consideration and design might make a fine low-level amp stage, but this is definitely not a beginners opamp, you surely must agree with me on this!
In closing, I find it ironic that a whole community of audio enthusiasts that have joined the hobby to "improve" on commercial manufacturers offerings, sabotage themselves and their fledgling members with subjectivist claims and rhetoric that are counter-productive of their goals in obtaining a true:
"hi-fi system built from my own two hands and didn't cause me to default on my house mortgage".
Isn't that what most of us are after?
Sincerely,
Brannon
I guess the bottom line with subjectivism is this. When I was growing up, my family wasn't rich. My parents couldn't afford to buy me the $10K Mark-Levinson amp (a cheap one) I listened to when I would make my weekly trips into LA to the high-end audio salons (I would bug the hell out of the snooty sales people too). I was the kid that would drool all over the articles from my latest issue of Audio Magazine (as many of you here probably did) and dream of someday owning equipment like that. As you get older, graduate from college and enter the workforce, the reality of your life sets in and you conclude and accept that you will be of retirement age when you might actually be able to acquire such equipment. The reason is that you've become aware that shelter, transportation and food take precedence over "a hobby". Such are the cruel realities of life.
Because I am older and must work hard for what I have (and being a technical minded individual), I get a little irate when I see advertisements for "subjectivist" items like:
"$500 24ct gold-plated mains power cables designed for the demanding audio enthusiast"
As if the last six feet of cable is going to make up for the 10000ft of "generic" cable your electrical utility company ran from the generation plant to your house.
It's this kind of snobby, pricey, unobtanium, elitest, snake oil, black magic, wizardry that I detest. I must have equipment (or design equipment) that is true, clinical, analytical, adds no coloration of it's own, the proverbial "straight wire with gain". And if you can't justify a components cost with it's measurable performance, then it's spec sheet isn't worth the paper it's printed on. I do believe that there are high end audio components out there that do deserve to fetch the high sums of money they sell for, because they look and are constructed as good as they sound. But there seem to be a myriad of companies out there trying to sell their idea of "Audio Euphoria" complete with 20kHZ THD in the 3-5% range, for an unbelievable amount of cash. They say a fool and his money are easily separated, and this fool works to hard to let it go that easy.
I also feel it's poor policy for senior members of this forum to recommend AD825 to people that have little experience in this field, you are doing them a great disservice. Most people on this forum I think will agree with me on this if they think about it. If you go to the AD site, it's stated right there in the description of recommended uses for this IC, it was intended for "video and portable instrumentation" there is not one mention of it's use in audio equipment, being the company that designed the IC, wouldn't AD make a claim for audio if it could? I am not saying it CAN'T be used in an audio environnment (I would say it's far from an ideal candidate though) and with careful consideration and design might make a fine low-level amp stage, but this is definitely not a beginners opamp, you surely must agree with me on this!
In closing, I find it ironic that a whole community of audio enthusiasts that have joined the hobby to "improve" on commercial manufacturers offerings, sabotage themselves and their fledgling members with subjectivist claims and rhetoric that are counter-productive of their goals in obtaining a true:
"hi-fi system built from my own two hands and didn't cause me to default on my house mortgage".
Isn't that what most of us are after?
Sincerely,
Brannon
tbla,
I do respect what your saying but the only way that could make a difference is if the original 6m (about 20 US feet) mains cable was made from extremely small guage wire and your amp is very high wattage. Other than that, what your saying defies that laws of physics except that your wallet probably got a lot lighter.
If your really curious test your theory, put on a blindfold and have a friend change the mains cable while you listen to the same music passage over and over. I'll bet you'll be wrong at least 50% of the time. If it really made a difference, you will be able to pick your "ultra-high end" cable almost every time.
Cheers!
Brannon
I do respect what your saying but the only way that could make a difference is if the original 6m (about 20 US feet) mains cable was made from extremely small guage wire and your amp is very high wattage. Other than that, what your saying defies that laws of physics except that your wallet probably got a lot lighter.
If your really curious test your theory, put on a blindfold and have a friend change the mains cable while you listen to the same music passage over and over. I'll bet you'll be wrong at least 50% of the time. If it really made a difference, you will be able to pick your "ultra-high end" cable almost every time.
Cheers!
Brannon
purplepeople,
the ne5532 is an industry standard made by several different companies (like a 2n4401 transistor) performance will be comparable between manufacturers, but I'm sure everyone out there will tell you his/her favorite. For what it's worth I use TI a lot and never had any trouble with them.
You could pay a lot more for an amp, and get a lot less. Don't be fooled by it's price.
the ne5532 is an industry standard made by several different companies (like a 2n4401 transistor) performance will be comparable between manufacturers, but I'm sure everyone out there will tell you his/her favorite. For what it's worth I use TI a lot and never had any trouble with them.
You could pay a lot more for an amp, and get a lot less. Don't be fooled by it's price.
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