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Post by gouge on Feb 24, 2017 1:56:29 GMT -6
DIY discrete converters.
Why has no-one done converters for the diy savy.
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Post by NoFilterChuck on Feb 24, 2017 2:01:10 GMT -6
have you opened up one of yours and looked at the number of components involved? DIY stuff is mainly thru-hole. the PCBs would be massive, considering all converters use surface-mount components to economize on the available space.
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Post by johneppstein on Feb 24, 2017 2:14:06 GMT -6
have you opened up one of yours and looked at the number of components involved? DIY stuff is mainly thru-hole. the PCBs would be massive, considering all converters use surface-mount components to economize on the available space. Plus, when you get into stuff operation in those extreme high frequencies, lead lengths can become critical. |
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Post by gouge on Feb 24, 2017 4:56:54 GMT -6
i'm not the one to work out the detail.
but you guys saying it can't be done just makes me think it can. like a prebuilt converter card with everything else diy.
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Post by NoFilterChuck on Feb 24, 2017 12:50:21 GMT -6
It's not that it can't be done. it's that the smart folks that did it said we shouldn't be doing this. Case in point: Ross Martin converters.
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Post by bowie on Feb 24, 2017 13:54:56 GMT -6
I've followed converter threads on GDIY and they usually go nowhere. I think there's less motivation anyhow as you can buy a great set of converters for $2,500 and that's all you need. With other gear, you're dropping that amount per pop and you can never get enough of the various comps, mics, pres, eqs, etc.
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Post by Deleted on Feb 24, 2017 15:52:33 GMT -6
I wouldn't call the svartbox topics nowhere. He built a converter that people seem to really like for much less than 2.5k. Discrete converters? Like in resistor ladder converters? There is a read-up on converters in Paul Horowitz, Winfield Hill "The Art of Electronics" 9.15 following. Could this be done DIY? Well, let's see... Yes, it can. BUT. (You know, the typical obstacles, small ones, that add up to undoable sometimes.) I guess the most critical stuff is matching of the precision resistors for linearity of the conversion and board design, of course. Svart roughly wrote up some information about what he did in his board design. With a boatload of professional experience of design in the HF spectrum, far above what we normally have to deal with in analog audio, where you have to think differently. But can it be done generally? Yes. Why not. I heard of a custom converter made for a german studio some years ago, that operated at 48kHz, 48bit(?!?), if i remember it right, they claimed that at their tests higher sample rates did not much if anything for more sound quality with this type of discrete converters, but higher resolution did. I have no clue, where i read about it, and if it even was a reliable source of information, and if it was, i have no clue what equipment they had available, or which skills the developer/s (?) had. Most certainly at least solid professional electronical engineering skills and quite some pro experience in analog and digital electronics. (I should start to collect all those internet sources of interesting things.....hrrrmmmm.) At least, here is a kind of "proof of concept" discrete converter project that has already been done and might be interesting to explore as a starting point. www.sonicillusions.co.uk/discrete_dac.htmAnd this is clearly, where my skills ended. But - there is always something to learn, and i am pretty sure it is not *impossible*... Most of the time things are impossible until someone did it and could proof it. I guess e.g. many people did not expect stuff like the RM or svart pro-audio converters possible at these price/performance ratios. Almost always somebody comes and say "impossible" because of whatever reason they find by estimating... In principle. I do not want to fingerpoint to forae of other color scheme, but we all know, that stuff like the GDIY community did never had happened if you listen to each seemingly well informed no-no and don't try to DIY. I still have these words in my ear... ("You can never recreate a vintage unit, not even in the ballpark, because" voodoo capacitors, black art resistors, the salvia of the technician that was a secret for whatever components production materials <insert alloy or plastic> and is lost forever since he died, blablabla.) And now look at the quality of kits that are available nowadays. And people like these. And use these. Because they simply are good and up to the state of art (of cloning or recreation or original design). Sorry for the rant. This is not against anyone on this board because IMHO this is one of the friendliest and most optimistic boards i know when it comes to solutions for problems, sharing of knowledge and wisdom, and motivation of our forum brothers. Same as GDIY, i guess. I really like, that i don't see, that there is condescendance or underestimation of the others here, and i particularly like this. There are some incredibly talented people around here, in many different fields. Even if we do only come to an evaluation of possibilities and some concrete numbers of specifications and the real world obstacles within these magnitudes, this has a value. Electronics always evolves. We have access e.g. to precision components that were simply unavailable decades ago, and sometimes this makes the crucial difference between possible or not. 0.1% precision resistors? Readily available without handpicking. For everyone. Each modern electrolyte is low ESR? (compared to....yes) etc.etc. Impossible yesterday does not automatically mean impossible tomorrow.... |
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Post by johneppstein on Feb 24, 2017 17:58:46 GMT -6
i'm not the one to work out the detail. but you guys saying it can't be done just makes me think it can. like a prebuilt converter card with everything else diy. No, it can't. You can't rewrite the laws of physics. If you read my previous post you OBVIOUSLY didn't understand its significance. LEAD LENGTH IS CRITICAL! That means that if the leads are too long the device simply will not work. That's because the leads in a UHF circuit like a digital processor function like little radio antennas and will interfere with to operation of other sections of the device - you get interference and coupling effects up the wazoo. You know how interference causes problems in the audio domain? Well, this is a thousand times worse. That's why they invented surface mount devices in the first place, to keep the lead and trace lengths short. additionally when frequencies get that high a disparity in distance can throw off phase and timingt relationships to the point where things that need to be in sync aren't.
You can't build a functional digital device of the complexity of an audio converter with through-hole construction. Furthermore, such a device requires a very high component density with extremely well thought out layout to avoid interference problems. Unfortunately nearly all DIY types lack both the equipment and the expertise to deal with high density SMT. Dealing with ultra high density digital processing chips require special soldering ovens to simultaneously solder very large numbers of connections reliably at the same time and things like that are too expensive for the hobbyist.
Now a prebuilt converter card with everything else DIY is possible, but it's pointless. There isn't much of anything left to do. It's like saying saying you're building a car when the whole thing comes assembled except you bolt on the wheels. That's not DIY, that's pretending. |
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Post by johneppstein on Feb 24, 2017 18:45:03 GMT -6
I wouldn't call the svartbox topics nowhere. He built a converter that people seem to really like for much less than 2.5k. Discrete converters? Like in resistor ladder converters? There is a read-up on converters in Paul Horowitz, Winfield Hill "The Art of Electronics" 9.15 following. Could this be done DIY? Well, let's see... Yes, it can. BUT. (You know, the typical obstacles, small ones, that add up to undoable sometimes.) I guess the most critical stuff is matching of the precision resistors for linearity of the conversion and board design, of course. Svart roughly wrote up some information about what he did in his board design. With a boatload of professional experience of design in the HF spectrum, far above what we normally have to deal with in analog audio, where you have to think differently. But can it be done generally? Yes. Why not. I heard of a custom converter made for a german studio some years ago, that operated at 48kHz, 48bit(?!?), if i remember it right, they claimed that at their tests higher sample rates did not much if anything for more sound quality with this type of discrete converters, but higher resolution did. I have no clue, where i read about it, and if it even was a reliable source of information, and if it was, i have no clue what equipment they had available, or which skills the developer/s (?) had. Most certainly at least solid professional electronical engineering skills and quite some pro experience in analog and digital electronics. (I should start to collect all those internet sources of interesting things.....hrrrmmmm.) At least, here is a kind of "proof of concept" discrete converter project that has already been done and might be interesting to explore as a starting point. www.sonicillusions.co.uk/discrete_dac.htmAnd this is clearly, where my skills ended. But - there is always something to learn, and i am pretty sure it is not *impossible*... Most of the time things are impossible until someone did it and could proof it. I guess e.g. many people did not expect stuff like the RM or svart pro-audio converters possible at these price/performance ratios. Almost always somebody comes and say "impossible" because of whatever reason they find by estimating... In principle. I do not want to fingerpoint to forae of other color scheme, but we all know, that stuff like the GDIY community did never had happened if you listen to each seemingly well informed no-no and don't try to DIY. I still have these words in my ear... ("You can never recreate a vintage unit, not even in the ballpark, because" voodoo capacitors, black art resistors, the salvia of the technician that was a secret for whatever components production materials <insert alloy or plastic> and is lost forever since he died, blablabla.) And now look at the quality of kits that are available nowadays. And people like these. And use these. Because they simply are good and up to the state of art (of cloning or recreation or original design). Sorry for the rant. This is not against anyone on this board because IMHO this is one of the friendliest and most optimistic boards i know when it comes to solutions for problems, sharing of knowledge and wisdom, and motivation of our forum brothers. Same as GDIY, i guess. I really like, that i don't see, that there is condescendance or underestimation of the others here, and i particularly like this. There are some incredibly talented people around here, in many different fields. Even if we do only come to an evaluation of possibilities and some concrete numbers of specifications and the real world obstacles within these magnitudes, this has a value. Electronics always evolves. We have access e.g. to precision components that were simply unavailable decades ago, and sometimes this makes the crucial difference between possible or not. 0.1% precision resistors? Readily available without handpicking. For everyone. Each modern electrolyte is low ESR? (compared to....yes) etc.etc. Impossible yesterday does not automatically mean impossible tomorrow.... Well, yes and no. Yes, electronics is progressing rapidly. Unfortunately one of the effects of this is that modern electronics have pretty much moved beyond the realm of the typical basement tinkerer. There's a big difference between recreating a device based on pre-1980s tech and something based on 2000s tech that's manufactured in a highly automated factory by precision robots operating in a clean room. It's one thing to say the some vintage thing "can't be recreated" because the old (relatively low tech) components aren't around much and all the old assembly people are passed on. Any skill that somebody once had can be recreated and learned by someone else with enough time, determination, and intelligence. That's not true of a device that requires a precision industrial robot to assemble. Sure, somebody whose job it is to work with that level of electronics can design a device and probably has the connections to get the high-tech assembly done so they can produce a small run - like Svart. Is this REALLY DIY, as the term is generally understood? I don't think so. It's small run design and manufacturing. It seems to me that modern electronics has pretty much evolved beyond the ability of DIY. That's why you don't see neighborhood electronic repair shops anymore, and the places that service your computer just pull out the old board and stick in a new one, with no attempt to repair anything on the component level. The audio community is one of the very few and very rare places where electronics as it was one practiced is still viable - but on a limited basis, kept alive because the old technolgy did things that are more suited to the artistic goals that are the foundation for everything - but as electronics progresses and new technologies are adopted for new procedures we're getting manufactureing technologies involved that are very unfriendly to the individual tech as we've known him in the past. And you have to know and understand what the limitations are. The area for future DIY on the digital side lies primarily in the coding realm, I'm afraid, not the assembly of circuiitry. I don't like it, but it's the way of the future. |
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Post by gouge on Feb 24, 2017 18:47:51 GMT -6
I wouldn't call the svartbox topics nowhere. He built a converter that people seem to really like for much less than 2.5k. Discrete converters? Like in resistor ladder converters? There is a read-up on converters in Paul Horowitz, Winfield Hill "The Art of Electronics" 9.15 following. Could this be done DIY? Well, let's see... Yes, it can. BUT. (You know, the typical obstacles, small ones, that add up to undoable sometimes.) I guess the most critical stuff is matching of the precision resistors for linearity of the conversion and board design, of course. Svart roughly wrote up some information about what he did in his board design. With a boatload of professional experience of design in the HF spectrum, far above what we normally have to deal with in analog audio, where you have to think differently. But can it be done generally? Yes. Why not. I heard of a custom converter made for a german studio some years ago, that operated at 48kHz, 48bit(?!?), if i remember it right, they claimed that at their tests higher sample rates did not much if anything for more sound quality with this type of discrete converters, but higher resolution did. I have no clue, where i read about it, and if it even was a reliable source of information, and if it was, i have no clue what equipment they had available, or which skills the developer/s (?) had. Most certainly at least solid professional electronical engineering skills and quite some pro experience in analog and digital electronics. (I should start to collect all those internet sources of interesting things.....hrrrmmmm.) At least, here is a kind of "proof of concept" discrete converter project that has already been done and might be interesting to explore as a starting point. www.sonicillusions.co.uk/discrete_dac.htmAnd this is clearly, where my skills ended. But - there is always something to learn, and i am pretty sure it is not *impossible*... Most of the time things are impossible until someone did it and could proof it. I guess e.g. many people did not expect stuff like the RM or svart pro-audio converters possible at these price/performance ratios. Almost always somebody comes and say "impossible" because of whatever reason they find by estimating... In principle. I do not want to fingerpoint to forae of other color scheme, but we all know, that stuff like the GDIY community did never had happened if you listen to each seemingly well informed no-no and don't try to DIY. I still have these words in my ear... ("You can never recreate a vintage unit, not even in the ballpark, because" voodoo capacitors, black art resistors, the salvia of the technician that was a secret for whatever components production materials <insert alloy or plastic> and is lost forever since he died, blablabla.) And now look at the quality of kits that are available nowadays. And people like these. And use these. Because they simply are good and up to the state of art (of cloning or recreation or original design). Sorry for the rant. This is not against anyone on this board because IMHO this is one of the friendliest and most optimistic boards i know when it comes to solutions for problems, sharing of knowledge and wisdom, and motivation of our forum brothers. Same as GDIY, i guess. I really like, that i don't see, that there is condescendance or underestimation of the others here, and i particularly like this. There are some incredibly talented people around here, in many different fields. Even if we do only come to an evaluation of possibilities and some concrete numbers of specifications and the real world obstacles within these magnitudes, this has a value. Electronics always evolves. We have access e.g. to precision components that were simply unavailable decades ago, and sometimes this makes the crucial difference between possible or not. 0.1% precision resistors? Readily available without handpicking. For everyone. Each modern electrolyte is low ESR? (compared to....yes) etc.etc. Impossible yesterday does not automatically mean impossible tomorrow.... now that's very cool. awesome idea. when I used the words discrete I was meaning the input and output stages. didn't realise it could be taken further. |
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Post by gouge on Feb 24, 2017 18:50:00 GMT -6
i'm not the one to work out the detail. but you guys saying it can't be done just makes me think it can. like a prebuilt converter card with everything else diy. No, it can't. You can't rewrite the laws of physics. If you read my previous post you OBVIOUSLY didn't understand its significance. LEAD LENGTH IS CRITICAL! That means that if the leads are too long the device simply will not work. That's because the leads in a UHF circuit like a digital processor function like little radio antennas and will interfere with to operation of other sections of the device - you get interference and coupling effects up the wazoo. You know how interference causes problems in the audio domain? Well, this is a thousand times worse. That's why they invented surface mount devices in the first place, to keep the lead and trace lengths short. additionally when frequencies get that high a disparity in distance can throw off phase and timingt relationships to the point where things that need to be in sync aren't.
You can't build a functional digital device of the complexity of an audio converter with through-hole construction. Furthermore, such a device requires a very high component density with extremely well thought out layout to avoid interference problems. Unfortunately nearly all DIY types lack both the equipment and the expertise to deal with high density SMT. Dealing with ultra high density digital processing chips require special soldering ovens to simultaneously solder very large numbers of connections reliably at the same time and things like that are too expensive for the hobbyist.
Now a prebuilt converter card with everything else DIY is possible, but it's pointless. There isn't much of anything left to do. It's like saying saying you're building a car when the whole thing comes assembled except you bolt on the wheels. That's not DIY, that's pretending.well I guess you are not the man to figure it out then. |
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Post by johneppstein on Feb 24, 2017 21:09:17 GMT -6
well I guess you are not the man to figure it out then. What's to "figure out"? Can YOU rewrite physical law? If so, by all means, do it. I'm not talking about people claiming that something "can't be done" because of some religious reverence for the old vintage gear. I'm talking about things that are not physically possible without extremely sophisticated and expensive dedicated equipment. Are you physically capable of doing solder work on a high density SMT circuit board that uses VLSI chips? Do you even know what terms like SMT and VLSI mean? Can you reliably solder connections you can barely see on a four or six layer printed circuit board without damaging the components and/or the circuit board?
And then there's the software side. Are you up to rewriting the drivers every time the OS undergoes a significant update? Even if you are a competent coder, which is quite conceivable these days you's still need advance developer access to Apple and Microsoft's code to write the drivers. How many hobbyists have that?
Why don't you ask somebody who has successfully designed and built a converter what he thinks about the possibilities of putting out something like that as a DIY project? Or the chances of random members of the DIY community be able to successfully complete such a kit if he did make it available?
I'd think that the prospects of the resulting deluge of support requests would be enough to put such a project on permanent hold.
Many people DIY their own airplane. So far ONE person has successfully DIYed a private jet. You're asking the equivalent of the jet.
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Post by Deleted on Feb 24, 2017 22:42:35 GMT -6
Impossible yesterday does not automatically mean impossible tomorrow.... Well, yes and no. Yes, electronics is progressing rapidly. Unfortunately one of the effects of this is that modern electronics have pretty much moved beyond the realm of the typical basement tinkerer. There's a big difference between recreating a device based on pre-1980s tech and something based on 2000s tech that's manufactured in a highly automated factory by precision robots operating in a clean room. It's one thing to say the some vintage thing "can't be recreated" because the old (relatively low tech) components aren't around much and all the old assembly people are passed on. Any skill that somebody once had can be recreated and learned by someone else with enough time, determination, and intelligence. That's not true of a device that requires a precision industrial robot to assemble. Sure, somebody whose job it is to work with that level of electronics can design a device and probably has the connections to get the high-tech assembly done so they can produce a small run - like Svart. Is this REALLY DIY, as the term is generally understood? I don't think so. It's small run design and manufacturing. It seems to me that modern electronics has pretty much evolved beyond the ability of DIY. That's why you don't see neighborhood electronic repair shops anymore, and the places that service your computer just pull out the old board and stick in a new one, with no attempt to repair anything on the component level. The audio community is one of the very few and very rare places where electronics as it was one practiced is still viable - but on a limited basis, kept alive because the old technolgy did things that are more suited to the artistic goals that are the foundation for everything - but as electronics progresses and new technologies are adopted for new procedures we're getting manufactureing technologies involved that are very unfriendly to the individual tech as we've known him in the past. And you have to know and understand what the limitations are. The area for future DIY on the digital side lies primarily in the coding realm, I'm afraid, not the assembly of circuiitry. I don't like it, but it's the way of the future. Thanks for taking the time to answer in detail. You write that miniaturized electronics are not servicable anymore and it's just changing PCBs. Well. If you go to your local computer shop this might be true. Already at the next mobile phone service hub this might be slightly different. One of my last jobs was among administering several systems like knitting firmware recipies for automatic update over internet also analysis of codes of service repairs of mobile phones for fraud detection and prevention, so i had the chance to see, what our techs were able to repair. By hand. Not much special equipment. Precision pliers, hot air solder stations etc.pp.. Some of the tools and procedures have been built and set up from scratch, ehm, many....some stuff was just brilliant ideas from the guy next door... Say, e.g. very temperature sensible chips cooled with custom machined copper coolers to make it possible to do seemingly and previously impossible repairs on mobile phones. Stuff like that. It was a hi-tech center right next to the factory for the 3g and up phones before everything was transferred to china. Much was developed along the line by the factory workers or repair techs. Extremely high productivity and expertise for details at the same time. No black art. But super modern electronics that evolve lightning fast. Today 3000 of phone a, next day 5000 of b, you get the picture. Certainly this gave me a completely other picture of what is possible that sometimes you would never imagine, if you have a boatload of clever techs and engineers and whatever specialists are needed. And most things were trained on the job. Good thing - most of the time you do not ask IF something is possibel, but HOW. A DAC is obviously not the type of DIY that you throw together with self-etched board and a handful components after a pictured build manual. But nowadays it is not hard to order some prototype PCBs with 4 layers and if i want, i can repair a computer mainboard or whatever with a simple soldering iron. I already did solder and repair a computer soundcards with pretty small SMD components - with an elephant foot thick soldering iron. OK, this was a hard job. I guess it was a terratec or steinberg VSL2020 so something... But smaller does not mean you can only do it with robots. Much easier, than most people think. Actually, sometimes SMD works are faster than thru whole. Much of it is just a matter of the right glasses, calm hands and patience. Learning by doing. OK, the board design most probably is over my head. But also - it is not black art. Oh, this is a kind of discussion i like. Thanks for participating everyone... |
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Post by gouge on Feb 24, 2017 22:59:56 GMT -6
Yup design is about ideas not pages of excuses in why not.
There are many dac kits available already in the audiophile world.
Maybe a simple solution is a buffalo iii with some capi line amps.
That would allow 8 channels da via aes.
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Post by gouge on Feb 24, 2017 23:17:23 GMT -6
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Post by Deleted on Feb 24, 2017 23:53:07 GMT -6
As for the code side of things... It is certainly right, that writing drivers for audio cards is a freaky mess to do, even if you are an experienced programmer. Tried working on some virtual audio device drivers for windows. No fun. No fun at all. So, you can avoid this. SPDIF in/out. Devices with class compliant usb audio interface (OS standard drivers under all OSes incl. Linux...), there are some great building blocks available nowadays. No need to reinvent the wheel. Programming microprocessors is a bit tricky, but much more comfortable, as it used to be. Is it easy? No, certainly not, but depends on the overall concept of what you want to achieve. Is it legit DIY to take a device and use it to build something different out of it? I think yes, your mileage may vary. As long as you create something different out of it. Why not taking a cheap converter, use the infrastructure, but use another converter chip and analog output/input/filtering? With a discrete opamp out? Transformers? Why not. If you get something useful out of it, i think it is legit. Modding is also DIY. Jim Williams made a great suggestion for this kind of experiments to start with. Get yourself an evaluation board from TI and then go for it for making it great with new input/output stages without compromise, quality PSU, and in the end get a great converter that is much more than a proof of concept. AFAIK he wrote he used/uses such a converter himself for years. The obvious candidates for quality are the pcm1794 for dac and 4222 for ADC or maybe some of the great ESS Sabre chips. The svart converter as a concept was aiming at a completely built from scratch full fletched great quality ADC(DAC. Of course this was a a very high level project from start. And i am sure many people watched the progress suspiciously and did expect it to fail or not to reach the quality goal. But it didn't. Not even at this high level of engineering. Is this DIY? Sure. I mean, he did it and oone else, and svart had and has every reason to be proud of it. I feel it is totally legit to get as much of the critical digital work out of the way and concentrate on what happens at the I/O, conversion and filtering stages. There is no need to prove, that you are incredibly multi-talented, there is no rule about what is allowed and what not (as long as it doesn't break juristical laws). The word pretending sounds a little bit harsh, but o.k., i see the point. We don't have to agree on this. Btw. since i now understand the original idea of "discrete" in this context, i can recommend watching out for other DIY projects that are around for quite some years. Just for analysis and inspiration. E.g. this one... www.dddac.com/documents/dddac1794_nos_ver30.pdfOK. a relaxing joke: What is a Behringer ADA8000 modded to have a micpre-frontend of 8 green pre's into the ADCs instead of the (not particularly bad) Behringer pre's? ǝɯosǝʍɐ I see this here as a kind of brainstorm session, so it is ok to make suggestions and critical annotations as well... |
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Post by Deleted on Feb 25, 2017 0:29:47 GMT -6
Ohe thing, that just came to my mind after re-reading Johns comments.
Nowadays the definition of "DIY" often includes "kits", "boards" and then "paint-by-numbers support" for many people that buy in and don't even have a 10 bucks DMM, let alone LCR meter or the will to dive into the matter - themselves.
Well this is pretty much the reason why i do not write at GDIY anymore (and i am not the only one...).
I already think a schematic can already be a generous gift to the community. Some hot tips and hints. A suggestion. A theoretical explanation. Stuff like that....
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Post by Bender on Feb 25, 2017 1:08:07 GMT -6
now, is love sweet love
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Post by johneppstein on Feb 25, 2017 1:31:31 GMT -6
Thanks for taking the time to answer in detail. You write that miniaturized electronics are not servicable anymore and it's just changing PCBs. Well. If you go to your local computer shop this might be true. Already at the next mobile phone service hub this might be slightly different. One of my last jobs was among administering several systems like knitting firmware recipies for automatic update over internet also analysis of codes of service repairs of mobile phones for fraud detection and prevention, so i had the chance to see, what our techs were able to repair. By hand. Not much special equipment. Precision pliers, hot air solder stations etc.pp.. Some of the tools and procedures have been built and set up from scratch, ehm, many....some stuff was just brilliant ideas from the guy next door... Say, e.g. very temperature sensible chips cooled with custom machined copper coolers to make it possible to do seemingly and previously impossible repairs on mobile phones. Stuff like that. It was a hi-tech center right next to the factory for the 3g and up phones before everything was transferred to china. Much was developed along the line by the factory workers or repair techs. Extremely high productivity and expertise for details at the same time. No black art. But super modern electronics that evolve lightning fast. Today 3000 of phone a, next day 5000 of b, you get the picture. Certainly this gave me a completely other picture of what is possible that sometimes you would never imagine, if you have a boatload of clever techs and engineers and whatever specialists are needed. And most things were trained on the job. Good thing - most of the time you do not ask IF something is possibel, but HOW. A DAC is obviously not the type of DIY that you throw together with self-etched board and a handful components after a pictured build manual. But nowadays it is not hard to order some prototype PCBs with 4 layers and if i want, i can repair a computer mainboard or whatever with a simple soldering iron. I already did solder and repair a computer soundcards with pretty small SMD components - with an elephant foot thick soldering iron. OK, this was a hard job. I guess it was a terratec or steinberg VSL2020 so something... But smaller does not mean you can only do it with robots. Much easier, than most people think. Actually, sometimes SMD works are faster than thru whole. Much of it is just a matter of the right glasses, calm hands and patience. Learning by doing. OK, the board design most probably is over my head. But also - it is not black art. Oh, this is a kind of discussion i like. Thanks for participating everyone... Well, yeah, I imagine that there are quite a lot of guys in the telecomm and computer industries who can hardware hack that kind of stuff prettty well. I even used to do a little of that myself on computer boards and hard drives when stuff was a bit simpler and I could still see close up, but I gave it up when the complexity got beyond me and age started catching up - but how many audio guys do you think are up to that? It's a whole different skill set than typical audio work. And it's a lot different when you have a large facility staffed with a "boatload of skilled techs" who are all swapping ideas than it is for guys working at home on their kitchen table. Where's a guy like that going to get a custom machined copper cooler so he can safely solder on a VLSI chip? I'm not saying it's impossible. I'm just saying that it's highly impractical and not cost effective. If it could be achieved with through-hole techniques it would simply be a very large scale and fiendishly complicated project, but I don't believe that through-hole would work on devices operating at gigahertz frequencies. And it seems to me that such a project would be far too labor intensive to be practical. |
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Post by johneppstein on Feb 25, 2017 1:39:27 GMT -6
Yup design is about ideas not pages of excuses in why not. There are many dac kits available already in the audiophile world. Maybe a simple solution is a buffalo iii with some capi line amps. That would allow 8 channels da via aes. Reasons, not excuses. And no, that's not a simple solution, it's DACs only, no input. No studio quality clock to keep everything in sync, either. If you're recording you need a/d. |
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Post by johneppstein on Feb 25, 2017 1:48:13 GMT -6
Ohe thing, that just came to my mind after re-reading Johns comments. Nowadays the definition of "DIY" often includes "kits", "boards" and then "paint-by-numbers support" for many people that buy in and don't even have a 10 bucks DMM, let alone LCR meter or the will to dive into the matter - themselves. Well this is pretty much the reason why i do not write at GDIY anymore (and i am not the only one...). I already think a schematic can already be a generous gift to the community. Some hot tips and hints. A suggestion. A theoretical explanation. Stuff like that.... Yes, that's what I'm thinking of and I'm making the assumption that this is the market that our friend Gouge is talking about as well. The guys that buy pre compiled kits from kit developers and build them. Not people like Svart. I'd call him an engineer (in the old sense), not a DIYer. Me, I'm a retired analog audio service tech, among other things. |
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Post by Deleted on Feb 25, 2017 3:13:53 GMT -6
OK. i come back to this for one more thing, just because it has been said that SMT is not good for conventional solder iron at home. Especially fine pitch packages with many legs.
This is simply not true. In fact, if you know, what you are doing, it is even very fast considering it is done by hand and even without special tools.
Flux, as always, is critical. You can even go so far, that you can solder most difficult looking packages with finest pitches with a conventional soldering iron - and you can even choose between different methods, flux+solder, flux+solder paste, using solder paste stencils, and even without using ANY SOLDER AT ALL (HASL board finish providing the solder itself, don't know if it works as slick for the other finishes like immersive tin and several others that gain more importance meanwhile, but HASL is most common anyway...).
And yes, you can use a reflow oven at home. You can even build a reflow oven at home. And there ARE people doing this, it is not some theoretical possibility.
But since i was a bit, let's say "not amused" about what was said in this thread about SMT and VLSI and how hard it would be to handle, i want to at least show off one way to do it at home.
It's the one that only needs flux. And a soldering iron. And the part and the PCB and nothing else.
And it is even the fastest one. Personally i prefer to use solder additionally, which is slightly more time consuming. I also like to use kapstan tape to hold the part while soldering, the standard pro way to do it, with very good results, but this here most of the time is as reliable from the contacts.
Now. I do know nobody who can solder 208 pins thru hole remotely as fast. With precision pliers and maybe a vacuum sucker you will have a hard time to find something you can not solder by hand as long as you can see it and your hand has no tremor...
SMT is probably the most misunderstood technology. It is comfortable, even for DIY. You do not even have to drill hundreds of holes if you make your own PCBs or reduce the cost of letting some be manufactured for you. Plus it saves space, why should this not be a potential advantage instead of an obstacle against DIY?
Watch.
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Post by Deleted on Feb 25, 2017 3:15:23 GMT -6
 Sure. Love is all you need.
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Post by Deleted on Feb 25, 2017 3:43:25 GMT -6
BTW...
I am with John in the point that i think designing a cool ADC makes much more sense for higher quality Input stages with maybe discrete opamps. For DAC i clearly prefer no color at all, so no vintage discrete opamp there.
One could - maybe - experiment with the Jensen transformers that are explicitly made to be put behind a DAC output.
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Post by johneppstein on Feb 25, 2017 17:11:36 GMT -6
OK. i come back to this for one more thing, just because it has been said that SMT is not good for conventional solder iron at home. Especially fine pitch packages with many legs. This is simply not true. In fact, if you know, what you are doing, it is even very fast considering it is done by hand and even without special tools. Flux, as always, is critical. You can even go so far, that you can solder most difficult looking packages with finest pitches with a conventional soldering iron - and you can even choose between different methods, flux+solder, flux+solder paste, using solder paste stencils, and even without using ANY SOLDER AT ALL (HASL board finish providing the solder itself, don't know if it works as slick for the other finishes like immersive tin and several others that gain more importance meanwhile, but HASL is most common anyway...). And yes, you can use a reflow oven at home. You can even build a reflow oven at home. And there ARE people doing this, it is not some theoretical possibility. But since i was a bit, let's say "not amused" about what was said in this thread about SMT and VLSI and how hard it would be to handle, i want to at least show off one way to do it at home. It's the one that only needs flux. And a soldering iron. And the part and the PCB and nothing else. And it is even the fastest one. Personally i prefer to use solder additionally, which is slightly more time consuming. I also like to use kapstan tape to hold the part while soldering, the standard pro way to do it, with very good results, but this here most of the time is as reliable from the contacts. Now. I do know nobody who can solder 208 pins thru hole remotely as fast. With precision pliers and maybe a vacuum sucker you will have a hard time to find something you can not solder by hand as long as you can see it and your hand has no tremor... SMT is probably the most misunderstood technology. It is comfortable, even for DIY. You do not even have to drill hundreds of holes if you make your own PCBs or reduce the cost of letting some be manufactured for you. Plus it saves space, why should this not be a potential advantage instead of an obstacle against DIY? Watch. Cool... What about those (relatively) new VLSI packages that have the contacts with little balls of solder under the chip package? Or are those only found on CPUs these days? |
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Sure. 