john curl said:
(After a brief interlude for supper, I come back to discover that a number of posts appeared after I hit Enter and trotted off to eat.)
John,
What on earth are you talking about? I looked back for several pages and found only one post (#5022) wherein I was talking about metal, but I confess that I can't see how what I said about copper could be construed as disagreeing with what you've said in any of your posts.
Jeez, man, I'm on your side...be careful where you swing that battle axe, okay?
Grey
john curl said:
John,
I find myself in agreement with most of the things you're suggesting with regard to burn-in. Yet, I'm still wondering if this article has any relevance to the current discussion.
Professionally, I have spent many years developing state of the art silicon process technology and I have had many TEM samples prepared for me to help understand the physical structure of what I'm building. My understanding is that in order to see anything in a TEM, the samples have to be thinned down to a few atomic layers. Otherwise, the electrons never make it through the sample and one doesn't see anything.
The reason I bring this up is that the behavior of atoms on a very thin sample is often very different from bulk properties. Just because grain boundaries in a very thin copper foil can move around in a vacuum after having a significant amount of energy dumped into them from the electron beam, doesn't necessarily tell us anything about what happens in bulk copper wires.
Sorry to rain on this particular part of your argument. It still doesn't change my agreement that burn-in is a real effect that I hear in many components.
---Gary
Sorry, Grey, I think I meant Gary.
And Gary, DUH. I can't spoon feed you everything that you refuse to learn on your own. I just spent about 4-6 hours looking through EVERY PAGE of those first two textbooks to find this article (about 1100 pages) at least 3 times, thinking that I missed what I was SPECIFICALLY looking for. You are going through the phase: 'It doesn't exist; it exists, but its not important; and we invented it' You are in the middle of this phase.
And Gary, DUH. I can't spoon feed you everything that you refuse to learn on your own. I just spent about 4-6 hours looking through EVERY PAGE of those first two textbooks to find this article (about 1100 pages) at least 3 times, thinking that I missed what I was SPECIFICALLY looking for. You are going through the phase: 'It doesn't exist; it exists, but its not important; and we invented it' You are in the middle of this phase.
john curl said:
Sorry, John, but you are way off base here.
Your advice would be like me telling you, "John, Mark Levinson (the man) and LG should be your target for your new preamp design. Trust me on this."
Joe Kane has done some good things for video. He has been one of the most vocal proponents for having standards (as found in the professional world) applied to video equipment in the consumer's home.
But JK is just as much about self-promotion as ML is. And also they both operate on about the same technical level.
KBK is talking about something on a completely different plane. Note the name he mentioned in one of his posts, "Chris Stephens". Chris is to video like Steve McCormack is to audio. Remember, SMcC invented Tip-Toes and made many other important discoveries that are taken for granted today. (Or maybe Enid Lumley would be another exemplar, or maybe Bob Crump.) Chris is not a circuit designer, per se. Instead, he took the best CRT projectors out there and re-built them to what you and I would call "audiophile standards".
The results were stunning, and without a doubt some of the best video playback achieved ever on this planet. For many years DTS used a Chris Stephens CRT projector in their over-the-top demos at CES.
I was tempted to do the same thing to a $40,000 Panasonic professional direct view CRT monitor. The picture quality in its stock form was shockingly good. But when you looked at the circuitry and the implementation you knew that everything could be brought to a completely new order of magnitude.
But people like Joe Kane don't care. Joe Kane only cares about Joe Kane and his bank account.
We used to make a DVD player that operated at that level. The difference in picture quality was just like in audio -- subtle, yet important. It was the difference between looking at a display and saying "Wow, that's got great detail!" and looking at a display and being mesmerized to the point where you couldn't stop watching until the movie ended.
But most people didn't care -- home theater attracts a different mentality than does audio. And the few that did care didn't want to pony up the big bucks for a DVD player when the high-res formats were announced.
And I'm not sure that it would even matter now. Back when we made our DVD player, the CRT projector was the acknowledged "king". Kind of like LP. But now the market has shifted almost completely to digital displays. And just like early digital audio, most digital displays suck raw eggs. DLP? The rainbows give me headaches after two minutes. LCD? The colors are completely artificial looking and there is too much time smear and not nearly enough contrast. The latest Pioneer plasmas were supposed to be almost as good as CRT, but I haven't seen one yet. I'm not sure if I will because Pioneer is shutting the plant down. They couldn't sell enough displays to make a profit because the mainstream video customers only look at two specs -- size and price.
KBK, I'd be interested to hear more about your ideas concerning digital video. Let me know if you are open to collaborating. I can't guarantee that there's any money to be made, but I can guarantee that I won't steal any of your ideas. (I only steal ideas from John!)
x-pro said:
Careful here. Drifts always exist and that's why each and every precision device or equipment is spec'd after 1 hour (or more) of running. We are talking here about some sort of irreversible changes that are happening in a a device, after a number of hours (or days, or weeks, or...) of "burning in".
Early semiconductor devices in the 50's and 60's were subject to such effects. Modern devices are much better, and are usually "burned in" in the factory anyway, mostly for QA and reability testing purposes.
But ultimately I can live with the idea of semiconductors needing a customer "burn-in" (btw, why do you think a semiconductor device gets better (for audio) after a whatever burn in?).
Where my physics is really failing me is in understanding the need to burn in a piece of silver wire. But then, what the
do I know?
I guess I just don't understand the mentality of many of the people posting to this thread. The topic is the "Blowtorch Preamplifier", which was designed by John Curl. There were a lot of people interested in this design, so they wanted to pick John's brain to get some ideas for their own DIY preamps.
But there is a strange group of hangers-on that insist on putting in their $0.02 worth of hot air.
Currently there is a debate about break-in.
"Is it real, or is it imagined?"
"Can you measure it?"
"Has it been demonstrated with double-blind testing?"
You know what? Nobody cares what all of these hangers-on think or don't think. People are reading this thread to hear *John Curl's* opinions. John has already given his opinion. He has backed up his opinion with some plausible mechanisms.
There really isn't much more to say. If you haven't done the tests, then John's opinions will hopefully spur you on to do so. But if you haven't done the tests, or if you *have* done the tests and can't hear a difference, please don't bother posting.
Nobody cares what a bunch of lazy and/or deaf people have to say about state-of-the-art audio design. On the other hand, they are very interested in John's experiences.
Thank you.
But there is a strange group of hangers-on that insist on putting in their $0.02 worth of hot air.
Currently there is a debate about break-in.
"Is it real, or is it imagined?"
"Can you measure it?"
"Has it been demonstrated with double-blind testing?"
You know what? Nobody cares what all of these hangers-on think or don't think. People are reading this thread to hear *John Curl's* opinions. John has already given his opinion. He has backed up his opinion with some plausible mechanisms.
There really isn't much more to say. If you haven't done the tests, then John's opinions will hopefully spur you on to do so. But if you haven't done the tests, or if you *have* done the tests and can't hear a difference, please don't bother posting.
Nobody cares what a bunch of lazy and/or deaf people have to say about state-of-the-art audio design. On the other hand, they are very interested in John's experiences.
Thank you.
Hi John and Charles,
This is a very interesting discussion and I know where you are coming from.
I was wondering if you might be appropriate to rationalise or summarise the findings and mechanism's into categories or sub groups.
I think this would support weeding out the specifics from the generalities and make any structured discussion more productive.
iMac
This is a very interesting discussion and I know where you are coming from.
I was wondering if you might be appropriate to rationalise or summarise the findings and mechanism's into categories or sub groups.
I think this would support weeding out the specifics from the generalities and make any structured discussion more productive.
iMac
macka said:
Funny you should ask. There is a guy who posts under the moniker "Dimitri". About a year ago, he compiled and organized everything that John had posted into one large document (PDF format). It has a *ton* of useful information and is available here:
http://www.diyhifi.org/forums/download/file.php?id=1201
NB -- You may need to register at this site in order to download the file, I'm not sure.
It's a little out of date now, largely because of the new information that has come up in this thread. But certainly a person could do worse than simply go through and spend a day or so cutting and pasting John's pearls of wisdom into a convenient format such as Dimitri did. If anyone is so inspired, please share it with the rest of us, as it would be greatly appreciated.
Charles Hansen said:
Kinda makes you itchy when looking inside there, doesn't it? The only thing you know, is to prevent becoming involved in a giant headache the size of Kansas, as you are going to do it right..means getting the cover back on that unit and pretend you never ever saw what it looked like in there. Maintain your ignorance! I failed. I went into it with the intent of looking inside.
I can fix most technologies quite well. DLP, I can kill the rainbows, for the most part, along with a bunch of other issues that folks don't really understand are there...until you point them out as being absent in the modified unit.
A tentative yes. I'm also looking for gear for my 'other' company. The one with the new interesting products, ones that bear a huge relevance to what you are doing right now, namely, audio. Also, my biz partner is a huge bicycling fanatic. Ie, campi/colnago kinda hardcore. And he's a mechanical/ acoustical noise control nightmare machine with literally no peer, in my experience. He makes world class physicists sit down and cry -they simply have no idea. I'll send you the link of the other company, if you are not aware what I'm speaking of. I can guarantee it'll knock you right out of your chair when you find out what it is.
The high def format war has stabilized for the foreseeable short future, which means making a unit has become a viable thought, at the least..finally. But..speed is everything here, as you may well know. The design cycles in that world are horrifically short. But the recent stabilization at blue-ray and 1080P has given us a potential breather of about 2 years. maybe three. we hope.
Far be it for me to speak for John, but...Charles Hansen said:
Let's see, Blowtorch: over 200 forum pages, several snippets of circuit bits, lots of discussion about balanced design and cascode topologies, several submissions of others designs with John's critique, John's discussion of proper power supply design, grounding and shielding. John's experience with jFEts and circuit topologies.
We are unlikely to see an exact schematic, after all this is how John makes his living. For all we know he is contractually limited from disclosing all circuit details by his clients.
Everything anyone competent in the art needs to make a reasonable facsimile of John's design, maybe not quite as good but damn close.
What do you want? Have John build you a free one and send it to you for Christmas?
It's a forum, not a classroom or lecture hall, discussions are the raison de etre of the all the threads on the forum. Sending sonar pulses into the brains of the older hands to see what echoes back is a good use of forum space.
Just my opinion.
john curl said:You tell 'em Charles!
I really do wish that all of you would go to that website and get my old info. THEN, I could move forward here.
The compilation was made from ‘borrowed’ posts here at Diyaudio and locked up in a ‘members-only’ area. I’m not a member over there nor did I hack myself into that members-only area and no one gave me the file.
There’s nothing in that PDF that has not been written here and some parts have been altered from their original posts.
Better read John’s posts in their full context over here.
/Hugo
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