thank you
I am sincerly grateful to all those who contributed to my coronation, of being the First who discovered the high temperature character of LM3886, depriving the creator of the Gaincard, Junji Kimura from his title.
But, he can continue laughing at the gaincloners.
I am sincerly grateful to all those who contributed to my coronation, of being the First who discovered the high temperature character of LM3886, depriving the creator of the Gaincard, Junji Kimura from his title.
But, he can continue laughing at the gaincloners.
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You are a bit strange mate, I have posted very little on here and most of it just saying running electronics hot is not a good idea, if that's bullying then something is wrong... Unlike of course what you are doing in regards to myself... think about it and keep me out of your posts.
So, you have tried running such chipamps at elevated (and known) temperatures.
Do you have a temperature preference zone, and can you describe your preference reasons.
Thanks, Dan.
What does one do with that? You were part of the thread. Have you gained some especially high petard that puts you above comment? I assume you know what a petard is.
Everyone knows that heat is usually not a good idea for electronics unless they are filaments/heaters and such. Not exactly something new.
You made your comments after someone had written how a real life product was using heat as a means to an end and you go on about how dangerous and destructive it is. The product in question has no reputation for unreliability yet you continue with the "pedantics".
The best way to stay out of anyone's posts is to not be involved in topics you have no interest in other than telling the OP how wrong and dumb they are. It would be edifying if you had experience with the device in question and were giving a warning based upon something that happened to you.
I don't think I have ever read of someone telling someone they cannot mention them in a post. But then I am the strange one.
Fine with me. You could settle this completely by not involving yourself in topics you have no real interest in. In fact, I do not think I have ever read a post by you on something you were actually engaged with but it would be impossible for anyone to claim they have read a tenth of the posts here.
What you and Julf did to the SDTrans thread makes it hard to believe anyone could puff themselves up so righteously about a basically complimentary comment which I sincerely believe to be true. In fact, your PM to me kind of gave the game away.
I would enjoy few things more than never mentioning you in a post again. That does make it a two way street.
Cordially
Rick: Marce works with REAL electronics. You know mission critical, people die if it goes wrong type things. Where MTBF needs to be decades in some cases. Not sure why you are getting uppity about him pointing out the bleeding obvious that silicon doesn't like being too hot.
As for the 47 labs gain card, give 6 loons a miss and read this 47 Laboratory 4706 Gaincard power amplifier | Stereophile.com . My the review sample went bang.
The measurements are about the worst I have ever seen for a chip amp. The fact that it costs a fortune measures worse than a cheap AV receiver and would not meet CE approval in europe as runs to hot are hardly glowing recommendations. I have a 50 year old tube amp that has better measurements than this overpriced and overhyped example of the worst of boutique audio.
As for the 47 labs gain card, give 6 loons a miss and read this 47 Laboratory 4706 Gaincard power amplifier | Stereophile.com . My the review sample went bang.
The measurements are about the worst I have ever seen for a chip amp. The fact that it costs a fortune measures worse than a cheap AV receiver and would not meet CE approval in europe as runs to hot are hardly glowing recommendations. I have a 50 year old tube amp that has better measurements than this overpriced and overhyped example of the worst of boutique audio.
I certainly never impugned a certain person's engineering abilities.
I am mystified by this post, too.
We are talking about the reliability of a LM3875 being compromised by heat.
This report is about a defective outboard power supply. From a review in 2001.
I have never seen a GAINCARD much less heard one but I did use four LM3875s many years ago. I followed the recommendations of Peter Daniel. I thought they sounded pretty good considering how little money I had invested in them and think they serve a great purpose for those without lots of money or are unwilling to spend lots of money on gear.
There have been lots of people impressed by the sound of the thing. Maybe they are all nuts! I have never seen the results of any testing of the thing. Of course, I agree the thing is absurdly overpriced. The thing is not the GAINCARD but the LM3875/3886 and how to get the most out of it.
We all know good measurements are not indicators of great sound. I agree that an amplifier that measured truly bad will likely sound bad but we also know that great measurements have little to do with better than average sound. I am not one who would expect an LM3875 to sound better than just about any tubed amplifier but, again, they can make for a simple decent sounding project at a minimum. I love the idea that someone like kokoriantz might find something that makes it the proverbial David. I know it is not likely but it would be neat.
So you know I am not a cheerleader. I think there are many absurd comments made about these chips along with the GAINCARD ad copy. Trying to convince someone that the circuit is some minuscule length when there could be miles of traces within a chip. I personally think it is impossible that either of these chips could ever sound as good as what I am using but I would welcome someone trying to make it so and would cheer them if they succeeded.
I replaced mine with a FIRST WATT J2 and SIT1s.
When this thread got my notice I found it intriguing since I went to much too much trouble to keep them cool. I know I never heard them at their best. I do think kokoriantz stumbled upon something that had been overlooked and that kind of thing I find interesting. The old man bites dog story.
As I mentioned everyone, including myself, thinks of keeping components from frying themselves. Here was a case where the expected solution turns into a problem. Intriguing.
As far as I could tell kokoriantz made his points clearly and yet all that is written is conventional wisdom that ignores what he said.
The STEREOPHILE article is the anomaly. I read reviews of this thing in many magazines and other than this instance of power supply failure in a new component which is when most of them occur, I have never heard of this thing having problems.
I have not verified for myself that the chip is being run as hot as kokoriantz says it is but then, I believe him.
SO I remain mystified why in a forum that is based upon people doing things for themselves, whether construction or thinking, why there is a contingent that seems to say DO NOTHING other than what has been done one hundred times before? No need for forum if that is the case. All we would need are recipe pages.
I like to think this is a community of adults who do not need constant supervision by people they do not know. I am sure a certain person has great abilities but I have never read of him offering anything but cautionary messages that come across as paternal. If we were all twelve years old this would be appreciated. Paternal at best. Some are as if there is actually a burning bush writing the post. This certain person is not alone. There are others but luckily not lots of others.
I have also told a certain person of my great respect for how he has lead his life - not that I know lots but a man who has raised seven children gets my admiration and respect. This does not mean he becomes immune to any criticism. I stand by my comment that some people enjoy taking potshots in random threads for which they have not the slightest interest. Many make random comments within posts and most are easily dismissed. I tend to think _____'s comments have a snide edge to them unbecoming of a man of accomplishment. And when one knows more of his stature it becomes more mystifying, not less.
If that is to be encouraged here, fine. But I think you will run off lots of folks who are enjoying what might be flights of fancy or serious enquiry if given a chance.
Just my strange point of view ...
I am mystified by this post, too.
We are talking about the reliability of a LM3875 being compromised by heat.
This report is about a defective outboard power supply. From a review in 2001.
I have never seen a GAINCARD much less heard one but I did use four LM3875s many years ago. I followed the recommendations of Peter Daniel. I thought they sounded pretty good considering how little money I had invested in them and think they serve a great purpose for those without lots of money or are unwilling to spend lots of money on gear.
There have been lots of people impressed by the sound of the thing. Maybe they are all nuts! I have never seen the results of any testing of the thing. Of course, I agree the thing is absurdly overpriced. The thing is not the GAINCARD but the LM3875/3886 and how to get the most out of it.
We all know good measurements are not indicators of great sound. I agree that an amplifier that measured truly bad will likely sound bad but we also know that great measurements have little to do with better than average sound. I am not one who would expect an LM3875 to sound better than just about any tubed amplifier but, again, they can make for a simple decent sounding project at a minimum. I love the idea that someone like kokoriantz might find something that makes it the proverbial David. I know it is not likely but it would be neat.
So you know I am not a cheerleader. I think there are many absurd comments made about these chips along with the GAINCARD ad copy. Trying to convince someone that the circuit is some minuscule length when there could be miles of traces within a chip. I personally think it is impossible that either of these chips could ever sound as good as what I am using but I would welcome someone trying to make it so and would cheer them if they succeeded.
I replaced mine with a FIRST WATT J2 and SIT1s.
When this thread got my notice I found it intriguing since I went to much too much trouble to keep them cool. I know I never heard them at their best. I do think kokoriantz stumbled upon something that had been overlooked and that kind of thing I find interesting. The old man bites dog story.
As I mentioned everyone, including myself, thinks of keeping components from frying themselves. Here was a case where the expected solution turns into a problem. Intriguing.
As far as I could tell kokoriantz made his points clearly and yet all that is written is conventional wisdom that ignores what he said.
The STEREOPHILE article is the anomaly. I read reviews of this thing in many magazines and other than this instance of power supply failure in a new component which is when most of them occur, I have never heard of this thing having problems.
I have not verified for myself that the chip is being run as hot as kokoriantz says it is but then, I believe him.
SO I remain mystified why in a forum that is based upon people doing things for themselves, whether construction or thinking, why there is a contingent that seems to say DO NOTHING other than what has been done one hundred times before? No need for forum if that is the case. All we would need are recipe pages.
I like to think this is a community of adults who do not need constant supervision by people they do not know. I am sure a certain person has great abilities but I have never read of him offering anything but cautionary messages that come across as paternal. If we were all twelve years old this would be appreciated. Paternal at best. Some are as if there is actually a burning bush writing the post. This certain person is not alone. There are others but luckily not lots of others.
I have also told a certain person of my great respect for how he has lead his life - not that I know lots but a man who has raised seven children gets my admiration and respect. This does not mean he becomes immune to any criticism. I stand by my comment that some people enjoy taking potshots in random threads for which they have not the slightest interest. Many make random comments within posts and most are easily dismissed. I tend to think _____'s comments have a snide edge to them unbecoming of a man of accomplishment. And when one knows more of his stature it becomes more mystifying, not less.
If that is to be encouraged here, fine. But I think you will run off lots of folks who are enjoying what might be flights of fancy or serious enquiry if given a chance.
Just my strange point of view ...
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That is truly awful. From the wobbles in the frequency response and the channel-to-channel interaction it is clear that they seriously screwed up the power supply and/or the supply decoupling. 0.3 % THD, 36 dB channel separation, plenty of mains-related IMD. That's a design fail in my opinion. They want $3300 for that?! Wow.
6 Loons. LOL! I like it.
Tom
I have no problem with experimenting. I do have an issue with evangelizing things that are somewhere between daft and dangerous. For those of us who have ended up with a TI logo burned into our fingers whilst fault finding and discovered something has got hot enough to melt the solder around it and now prefers to adhere to living flesh, we know that too hot can be bad. Running things at high temp requires some different considerations, especially if you have wife/kids/cat/dog etc.
I have no problem with people trying daft things or with them imagining improvements from them, but claiming its the new best thing since sliced bread despite everything pointing to it being detrimental should allow people to add a disclaimer. But this is a hobby. And in general the tolerance levels are high and there are a few millenia of real engineering experience on here to help people out. Some people though don't want to be helped...
I have no problem with people trying daft things or with them imagining improvements from them, but claiming its the new best thing since sliced bread despite everything pointing to it being detrimental should allow people to add a disclaimer. But this is a hobby. And in general the tolerance levels are high and there are a few millenia of real engineering experience on here to help people out. Some people though don't want to be helped...
I was on about you picking me out when I had only posted some minor comment, this is not the first thread you have done that to me. There were many other to pick on.
I am interested in electronic and in the case of chip amps have done more layouts than most on here using a variety of chip am devices. I get heavily involved in not only the layout, the enclosure, thermal issues and EMC, so while you may not agree with some things I say, they are comments based on 35+ years experience of working on and designing a variety of products and working for a wide customer base, so I have comments and advice that are pertinent to the discussion, just because I don't blindly follow every foolish idea like some doesn't make my views any less valid, in fact quite often more valid than some of the sh**e discussed.
These chip amp devices find themselves being used in numerous applications, even outside of audio such as small motor drives, there are even some mil gear that uses them to drive headsets and remote speakers. They are a useful little device, but do need to be respected, kept cool to work at their best and LAST. I do understand and know what a pain MTBF is, but also see the results of extended temp range testing etc.
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National says distortion increases because of limited open loop gain.
I wonder if the same effects as in this test applies to the lm3886?
http://www.ti.com/lit/an/slda031/slda031.pdf
That is open loop gain (and distortion) gets worse both with lower load resistance AND increasing die temperature.
The Miller measurements from link in post #88 indicates this. But has anyone made or seen measurements on distortion vs temperature?
I wonder if the same effects as in this test applies to the lm3886?
http://www.ti.com/lit/an/slda031/slda031.pdf
That is open loop gain (and distortion) gets worse both with lower load resistance AND increasing die temperature.
The Miller measurements from link in post #88 indicates this. But has anyone made or seen measurements on distortion vs temperature?
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I truly do not understand the objections to kokoriantz project . I have studied for long years and everything I have been taught points to keeping things as cool as possible. But lets stay openminded. Maybe he has a point and found something everybody has overlooked so far.
All I can say is I´m retired and , my skin being my radiator , am at equilibrium at 22 degrees. My aircon takes good care of that supplying heat in winter and withdrawing it in summer. 22 degress is the temperature at which I function best and don´t suffer from thermal runaways.
This being true for me myself and I it is more than possible that the same is true for the LM 3886 albeit at somewhat higher temperatures . What temperatures that might be I cannot say for lack of experience so my best option for the time being is to wait for Kokoriantz findings . In the meantime I´ll stick to 40 years of learning and experience . But I wish him best of luck.
All I can say is I´m retired and , my skin being my radiator , am at equilibrium at 22 degrees. My aircon takes good care of that supplying heat in winter and withdrawing it in summer. 22 degress is the temperature at which I function best and don´t suffer from thermal runaways.
This being true for me myself and I it is more than possible that the same is true for the LM 3886 albeit at somewhat higher temperatures . What temperatures that might be I cannot say for lack of experience so my best option for the time being is to wait for Kokoriantz findings . In the meantime I´ll stick to 40 years of learning and experience . But I wish him best of luck.
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There are a great number of posts has been erased, particularly tomchr humiliating me that higher temperature decreases the Hfe hence higher distortion, confirmed by another pretending expert andrewT. It is repeated on post 93. Of course any beginner in electronics learns the contrary, but the community against me with humiliating pictures re posted by tomchr, all erased now, one thing to do is walk away. To say that tomchr is not a diy but a professional earning his daily bread by LM3886 and wants the monopole of it.
I notice that since this thread, the title Gainclone, designating any circuit using LM3886 has disappeared.
I notice that since this thread, the title Gainclone, designating any circuit using LM3886 has disappeared.
If you read the press and magazines you will find a lot of critcism against the GAINCARD from all over though not outspoken but "between the lines" since it was and is a commercial product out on the market. It set a trend which has turned into an avalache concerning chip-amps and that is what is truly positive about it.
If Tom defends the LM3886 having worked at TI I find nothing wrong with that , on the contrary , I see it as a very positive and refreshing loyalty on his part . It is what I would do in his place . The very fact of him working for TI is a qualification he has and I do not.
And so are the amps he offers in his modulus series.
So forgive me if I tend to follow his teachings and listen carefully to what he has to say , as I do with several other members of this forum whose knowledge and expertise is proven by the very things they write.
If Tom defends the LM3886 having worked at TI I find nothing wrong with that , on the contrary , I see it as a very positive and refreshing loyalty on his part . It is what I would do in his place . The very fact of him working for TI is a qualification he has and I do not.
And so are the amps he offers in his modulus series.
So forgive me if I tend to follow his teachings and listen carefully to what he has to say , as I do with several other members of this forum whose knowledge and expertise is proven by the very things they write.
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