While waiting for my boards I decided to get a few more tda7297 chips, so I found some at a local supplier.
Upon closer inspection I found something interesting. The chips are marked different. The font is different and also the one that came from ebay has Singapore written on it. Logos are different marking style as well.
Did I get ripped off by my local supplier or is this thing normal?
Upon closer inspection I found something interesting. The chips are marked different. The font is different and also the one that came from ebay has Singapore written on it. Logos are different marking style as well.
Did I get ripped off by my local supplier or is this thing normal?
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Use a small cap or two near the chip, and a large one off the power tap in (or several).
The small bypass cap these come with creates ringing you can hear; when you take it out you'll realize how audible it happened to be. But 220uf Muse, SilmicII at the chip shouldn't make a ring with 2kuf+ not at the chip.
I think a good linear PSU would be best paired with this amp. It has poor noise rejection so your source needs to be clean or the TDA goes nuts with an SMPS.
After doing a bit of research on this subject I suspect that the ebay chip might be an improper called "fake". Better call them "rejected" production parts, as in they don't pass quality control. Basically they are thrown away, but somehow they end up on ebay. I was really squeezing my head trying to figure out how do they manage to make a profit on a 3.49$ device. There's the pcb, 3 connectors, one pot, heatsink and IC...and labor. I always discarded the chip itself from the calculus. I guess that's where they are making the profit actually, not on the other parts.
I'm saying it's not fake as it's working, and seems to be on spec as power output, so I guess that the risk here is getting a sub-standard chip. I am not even considering putting that chip into the new pcb.
This also explains my TA2020 amp. I also got a chip for backup some time ago and I saw that the writing on it looked better. The one from the ebay amp has perfect white writing, like silkscreen or something. I must find the time to replace that as well, I am not even going to consider ebay audio IC anymore. It's not worth the risk.
I'm saying it's not fake as it's working, and seems to be on spec as power output, so I guess that the risk here is getting a sub-standard chip. I am not even considering putting that chip into the new pcb.
This also explains my TA2020 amp. I also got a chip for backup some time ago and I saw that the writing on it looked better. The one from the ebay amp has perfect white writing, like silkscreen or something. I must find the time to replace that as well, I am not even going to consider ebay audio IC anymore. It's not worth the risk.
I can understand faking a Rolex or any other expensive high end product but what is there to gain in faking a cheap as dirt chip?
My ebay, unbuggered around with amps sound just great!
The datasheet doesn't seem to include marking layout. You might email the
pictures of the chips to ST Micro and inquire. Manufacturers are usually
interested to know if there are counterfeit parts out in the wild.
FWIW, the farnell pic looks like your first one:
TDA7297 - STMICROELECTRONICS - AMP, AUDIO, 15W, AB, MULTIWATT15 | Farnell UK
pictures of the chips to ST Micro and inquire. Manufacturers are usually
interested to know if there are counterfeit parts out in the wild.
FWIW, the farnell pic looks like your first one:
TDA7297 - STMICROELECTRONICS - AMP, AUDIO, 15W, AB, MULTIWATT15 | Farnell UK
The item that I received is authentic ST. It is too cheap to fake.
There is a higher power and a lower power version available in a different package. Both are ST.
Well, I just stated that they are not fakes in the real sense of the word, but parts that have been discarded by the production house as they are sub-standard. I guess it would be real expensive to acquire the tech necessary for them to clone something like this.
I'm only saying that it is a big chance that what we got from ebay might be a component that didn't pass the main producer quality standard, and have been discarded. Sure, they might sound good or behave properly but that isn't a guarantee that the part passed quality check. They could fail faster or even sound worse than a part that passed the quality check. Not counting the ones that let the magic smoke out. Electronic parts need the smoke inside or else they stop functioning as soon as it gets out
I'm only saying that it is a big chance that what we got from ebay might be a component that didn't pass the main producer quality standard, and have been discarded. Sure, they might sound good or behave properly but that isn't a guarantee that the part passed quality check. They could fail faster or even sound worse than a part that passed the quality check. Not counting the ones that let the magic smoke out. Electronic parts need the smoke inside or else they stop functioning as soon as it gets out
If you come to think about the profit margin on this little amp, you'd see that the most income would come from the chip itself as it's about 1.5$. On a 3.5$ product that's a nice profit.
And think about it this way. Cloning would presume some kind of effort, like scanning the original die, and reproducing it at some scale. You'd need a lot of cash for that. But taking the rejects that have already been built requires maybe a small bribe at the junk bin
So this seems more plausible now.
Especially since all of the parts that I saw coming from the west side of the world are like the ones that I sourced locally. The ones marked "Singapore" I saw only on ebay or alibaba etc.
There are another kind of "fakes" out there, but they presume the same pinout between an older very cheap device and more higher end ones. Something like op-amps, you can get burned real easy on those as they look the same and have the same pinout. All you need is a nicely done stencil.
If you come to think about the profit margin on this little amp, you'd see that the most income would come from the chip itself as it's about 1.5$. On a 3.5$ product that's a nice profit.
And think about it this way. Cloning would presume some kind of effort, like scanning the original die, and reproducing it at some scale. You'd need a lot of cash for that. But taking the rejects that have already been built requires maybe a small bribe at the junk bin
So this seems more plausible now.
Especially since all of the parts that I saw coming from the west side of the world are like the ones that I sourced locally. The ones marked "Singapore" I saw only on ebay or alibaba etc.
There are another kind of "fakes" out there, but they presume the same pinout between an older very cheap device and more higher end ones. Something like op-amps, you can get burned real easy on those as they look the same and have the same pinout. All you need is a nicely done stencil.
I have 4 7297 boards, purchased at different times, and they all sound equally great and I have not read otherwise from other purchasers.
I do not think you can tell a fake by the printing, they are not banknotes?
Perhaps a history of eastern European underhanded shoddiness has made you wary?
All the orders I have received from China have always been been of amazing value and worked beyond expectations!
The Chinese are predicted to overtake the US within 20 years, you do not achieve that by producing all crap.
Regarding the printing, I still think contacting ST Micro is a good idea.
Who knows, perhaps the different chips came from different FABs
that print things differently? (The datasheet contains no info on the
parts marking, unfortunately.) ST Micro should be able to tell you that.
If the die inside is a real but substandard TDA7297 not meant for sale
then ST Micro has a problem in its FAB and disposal operation. If it's
a complete fake then there are counterfeits. Either way, they probably
would be interested in knowing.
Who knows, perhaps the different chips came from different FABs
that print things differently? (The datasheet contains no info on the
parts marking, unfortunately.) ST Micro should be able to tell you that.
If the die inside is a real but substandard TDA7297 not meant for sale
then ST Micro has a problem in its FAB and disposal operation. If it's
a complete fake then there are counterfeits. Either way, they probably
would be interested in knowing.
I agree with radio. I have bought many DIY electronics from eBay vendors in China, from chips, PCBs to assembled boards. For the most part (99%) they all have worked out of the box and worked well. I've never had any magic smoke.I have 4 7297 boards, purchased at different times, and they all sound equally great and I have not read otherwise from other purchasers.
I do not think you can tell a fake by the printing, they are not banknotes?
Perhaps a history of eastern European underhanded shoddiness has made you wary?
All the orders I have received from China have always been been of amazing value and worked beyond expectations!
The Chinese are predicted to overtake the US within 20 years, you do not achieve that by producing all crap.
I've pretty much stuck with 2 vendors from Asia that I don't mind giving an unsoliticted shoutout to; Cristi (Connexelectronic.com), and along (eBay). I have been extremely happy with their respective products. Cristi's SMPS and amplifier modules are exceptionally well-built with quality parts and his craftsmanship superb. I think he builds most things to order. Along offers a myriad of parts, modules, cases, kits and in my opinion is a very trusted supplier. I've also bought from other suppliers like AliExpress, HiFimeDIY and others.
The Eiffel Tower is made from Romanian steel
, and Russian Tubes sound very good. Anyway, this was uncalled for.And yes, Chinese DO a lot of crap, most of it actually, when they are on their own with no quality standards. And yes, I saw many that prefer to pay 1$ for a crappy screwdriver that lasts them a few months (not for professional use) instead of paying 30 bucks for a German one
I have not yet found a Chinese product of high quality designed (or cloned mostly) and produced by them. I'm not saying they aren't making any, I'm just saying I haven't seen any. You know, stuff you use every day. And actually, this is how they achieved their economical power, by selling in volumes rather than large profit margins. Apart from overseas contracts with overseas quality controls.
As a side note about "Chinese products", a well known Romanian celebrity presented a case where a good friend of his bought some mobile phone covers from a site similar to DX. All good (and cheap, that what we're all after, right?) but after a week or so his friend developed a skin condition on his left side of the face. He waited and used some creams but the thing got even worse. Went to about 4-5 doctors, each scratching their heads and trying different remedies but nothing worked. Lucky for him, the first doctor he saw took it very seriously and made some research which prompted the question: "Sir, did you visit any Asian country lately?" That's when he linked the Asian products to the problem. It seems that some sort of parasite was on the phone cover and it transferred to his face when he used the phone. It's a terrible parasite, it eats the flesh, and very hard to treat (something found in that part of the world). Eventually he managed to cure it, but he suffered irreversible damage to that part of the face. All, because it was "cheaper" to buy from there instead of a reliable source where quality control really matters. Now, I'm not saying it's a high risk of something like this with Asian products, I'm just saying that it's a higher risk from that part then a more reputable source. You always get what you pay for, and there's no free lunch
There was another case with some delivery guys having some sort of stomach bug, but I can't remember the exact details. It was from the same part of the world, and equally hard to treat.Here's a link to it's blog entry, I guess you could translate it:
Cum te poate desfigura sau cum iti poate distruge sistemul digestiv telefonul mobil. – cabral.ro
After reading this entry I use alcohol on all products coming from ebay. Better safe than sorry.
This is certainly a possibility! I just sent an email to STMicroelectronics with pictures and all. I will post their answer on this matter.
I like to think the purchases I have made direct from China to be almost a free lunch, a tax free, shipping free lunch!
Amplifiers, TV dongles, speaker re-foam kits, cables, even plastic worms! All been great buys. I cannot say that for the Russian tires I once purchased when I lived in the UK, they wore out in less than 20,000 kilometres.
I love looking on ebay and Aliexpress and treating myself and waiting for the postman.
Amplifiers, TV dongles, speaker re-foam kits, cables, even plastic worms! All been great buys. I cannot say that for the Russian tires I once purchased when I lived in the UK, they wore out in less than 20,000 kilometres.
I love looking on ebay and Aliexpress and treating myself and waiting for the postman.
Chinese DO a lot of crap, most of it actually, when they are on their own with no quality standards. And yes, I saw many that prefer to pay 1$ for a crappy screwdriver that lasts them a few months (not for professional use) instead of paying 30 bucks for a German one
I have not yet found a Chinese product of high quality designed (or cloned mostly) and produced by them. I'm not saying they aren't making any, I'm just saying I haven't seen any. You know, stuff you use every day. And actually, this is how they achieved their economical power, by selling in volumes rather than large profit margins. Apart from overseas contracts with overseas quality controls.
Every time I saw someone comment about this topic, I wonder why didn't they think about the root cause. It is the people that are buying the "cheap stuff" that keep the cycle going. If the "cheap stuffs" are that bad, why are people still buying it?? Most of the stuffs that Walmart sells come from China, I do not see Walmart going out of business anytime soon. The stuffs that Walmart sell are everyday stuff, pretty much. Many prefer to pay $1 for a screw driver that would last for a few months because that serves the purpose. Why pay $30 for a German one that lasts forever? And they do not have the budget for a $30 screw driver. Same goes with the panel TV that Walmart sells. I can go on and on. Actually, I have heard some Chinese manufacturers complained that they can make a screw driver that has better quality than the $30 German one and it would cost only 25$. Sadly, westerner are not interested!!! The foreigner companies that come to China looking for contract manufacturing vendors are interested mostly in price.
I agree with you that a lot of crappy stuffs are made in China. But these crappy stuffs serve certain segments of the market. Why buy a "crappy cheap DMM" made in China instead of a top end Fluke or Agilent which will probably last a long long time? People cannot afford, that's why. The "cheap stuffs" allow more people to access stuffs that used to be available only to people that has a deep wallet. The downside would be that the "cheap DMM" would only last a few months under heavy use. More and more, we start to see the "cheap stuff" are getting less crappy. Some of those are actually getting quite decent, especially for the low price, as pointed out by Radiosmuck.
To stop those "cheap crappy stuffs" from getting out of China, let's stop buying them. I am all for it.
As a side note about "Chinese products", a well known Romanian celebrity presented a case where a good friend of his bought some mobile phone covers from a site similar to DX. All good (and cheap, that what we're all after, right?) but after a week or so his friend developed a skin condition on his left side of the face. He waited and used some creams but the thing got even worse. Went to about 4-5 doctors, each scratching their heads and trying different remedies but nothing worked. Lucky for him, the first doctor he saw took it very seriously and made some research which prompted the question: "Sir, did you visit any Asian country lately?" That's when he linked the Asian products to the problem. It seems that some sort of parasite was on the phone cover and it transferred to his face when he used the phone. It's a terrible parasite, it eats the flesh, and very hard to treat (something found in that part of the world). Eventually he managed to cure it, but he suffered irreversible damage to that part of the face. All, because it was "cheaper" to buy from there instead of a reliable source where quality control really matters. Now, I'm not saying it's a high risk of something like this with Asian products, I'm just saying that it's a higher risk from that part then a more reputable source. You always get what you pay for, and there's no free lunch
I think this is another one of those "story" that is floating in the internet. The celebrity's friend bought a bunch of those covers, why would only the one that the celebrity has caused the problem? The disease that you described is Necrotizing fasciitis, most commonly caused by bacteria. This disease can occur in many parts of the world, not just Asia. One of the former Prime Minister of Canada from Quebec lost a leg due to this disease. He was lucky to be alive.
Regards,
My amp worked very nice, that's not the issue here. I was just mentioning the possibility that these chips might be sub-standard. That is all.
People do buy cheap stuff, mostly because they cannot afford more expensive items. I saw plenty people that as they had more money they quit buying cheap ( and crappy ) items. This is a reality, not much philosophy here. Every item has it's market, and cheap chinese stuff helps a lot of people on this planet that couldn't get by otherwise.
I am NOT bashing the Asian market! All I'm saying is that we tend to get carried away with low prices. There are a lot of implications in this behavior. I've seen plenty cases where badly underpaid/underage workers get sick so we could pay 3.49$ instead of 8$. I can understand nationalities with less economical power to be happy about the prices...
Also I'm very happy with my ebay DAC, the case is nice and pcb looked proper. SMD parts were also nicely soldered on it. I agree that there is a good incentive to get stuff from ebay, small profit margins, and we get to diy a bit on the way. But most times the source from where you are buying matters a lot, like a known seller, with a good history among the diy community. They are a great help for our hobby!
But this does not mean that there aren't sub-standard parts (mostly) coming from Asia. Also if your chip sounds good that's not to say that it passed quality control! They aren't tested for that but for many other factors. That chip could last less than a proper one.
Regarding the fact that China will overtake US, well, that's the US's problem, mainly their citizens buying stuff from China. It's a matter of economical education. If you are not keeping your money in your own economy, it's logical that the ones who get it will have more economical power in the future. The US citizens are stimulating another country's economy. Sure, Asia wants less money for the same stuff, because they settle for less, they don't want more stuff, but to have food and shelter. The same applies for other nations as well!
Although this is an interesting topic to be debated, lets not get off topic here. I will end this saying that I am sorry if I offended anyone, that wasn't my intention here, but to bring into attention the fact that we need to keep an eye on quality as well. After all, we're trying to get the most out of our audio systems.
If I manage to finish my main speakers in the near future I promise I will make a comparison between the two chips and post objective results!