Hi !
I built a stereo amp with two 3886s, they were running with 33+33V each one with a 8Ohms Load (JBL E60).
They used to heat quickly, but it never burned... Supply just used to get warm.
Yesterday, I was very very tired, then I decided to listen some Quincy Jones, so I was connecting the amp to the supply and made a big mistake. The GND was connected to -VS and -VS to GND. Crash'n Boom hehehe, just one second (I heard HUMMMMMMMMMMM) and the amp was DEAD.
Hooooly Shiii...
Okay, very HAPPY I left all things in my living room and went to my bed to sleep.
Today in the morning, I ordered some 3886s from FARNELL, and they arrived four hours after I ordered it !
I fixed the amp and wheeeen I putted it to work... WHAT WAS THAT SOUND !?
Muuuchhh more LIVE, SPACED and the bass was much more tight ! The treble was much more focused and I could feel every instrument much more far from each other!
The woofer was moving much more less and producing a BETTER sound, and it was just WARM and not HOT like it used to be.
Anyway, I think it's strange a fake IC last all that time !
Here is some pictures, I'll be glad if you give me some feedback, saying if it is fake or not.
http://files.upl.silentwhisper.net/upload6/Photo-0041.jpg
http://files.upl.silentwhisper.net/upload6/Photo-0043.jpg
Thank you !!!
I built a stereo amp with two 3886s, they were running with 33+33V each one with a 8Ohms Load (JBL E60).
They used to heat quickly, but it never burned... Supply just used to get warm.
Yesterday, I was very very tired, then I decided to listen some Quincy Jones, so I was connecting the amp to the supply and made a big mistake. The GND was connected to -VS and -VS to GND. Crash'n Boom hehehe, just one second (I heard HUMMMMMMMMMMM) and the amp was DEAD.
Hooooly Shiii...
Okay, very HAPPY I left all things in my living room and went to my bed to sleep.
Today in the morning, I ordered some 3886s from FARNELL, and they arrived four hours after I ordered it !
I fixed the amp and wheeeen I putted it to work... WHAT WAS THAT SOUND !?
Muuuchhh more LIVE, SPACED and the bass was much more tight ! The treble was much more focused and I could feel every instrument much more far from each other!
The woofer was moving much more less and producing a BETTER sound, and it was just WARM and not HOT like it used to be.
Anyway, I think it's strange a fake IC last all that time !
Here is some pictures, I'll be glad if you give me some feedback, saying if it is fake or not.
http://files.upl.silentwhisper.net/upload6/Photo-0041.jpg
http://files.upl.silentwhisper.net/upload6/Photo-0043.jpg
Thank you !!!
The code is:
JM14BP
LM3886T
http://www.national.com/quality/marking_conventions.html
There's no "BP" here, or I'm blind?
And If you see the die, it isn't properly aligned.
Really fake?
JM14BP
LM3886T
http://www.national.com/quality/marking_conventions.html
There's no "BP" here, or I'm blind?
And If you see the die, it isn't properly aligned.
Really fake?
It is difficult to say wether it is genuine or fake since you have busted it open before taking a photo of the whole case. As for the die, I am not sure how it is attached in the LM3886 (I could crack open one of my genuine ones, but I think I'll rather keep it in one piece ), but it is not so uncommon to attach a die sideways if it makes it easyer to wire to the pin frame.
), but it is not so uncommon to attach a die sideways if it makes it easyer to wire to the pin frame.I got them from a small store on the city. Here's the Fake Town, if you ask for 2N3055 from toshiba, everybody will have it !
Then I ordered some from farnell !
I have more two burned ICs, I'll open them. If they're just like the "fake", I'll open a genuine from farnell !
Better loose some money and know what I'm putting on the boards!
Then I ordered some from farnell !
I have more two burned ICs, I'll open them. If they're just like the "fake", I'll open a genuine from farnell !
Better loose some money and know what I'm putting on the boards!
YES, they are fake !
There was no diference in the package, I placed the fake side by side with the original, and you can't see any diference.
I opened an 3886TF genuine, and I found what I was expecting. The genuine is better built and have the core perfectly aligned.
Some pictures again !
http://files.upl.silentwhisper.net/upload8/Photo-0047.jpg
http://files.upl.silentwhisper.net/upload8/Photo-0049.jpg
edit:
The most interesting is, it don't sound that bad !
Of course the genuine sounds MUCH better, but to a fake, isn't that bad ! hahahah
I used a lot the fakes, no problem heheh ! Used them with 33+33v @ 8Ohms, they were not noisy and I had no problems with them. I replaced them just because I did a mistake with the supply !
The fakes really surpassed my expectations!
Anyway, the genuine improved everything, since how tight is the bass now, till the amp efficience.
Be careful, anyone here can be using fakes without know !
There was no diference in the package, I placed the fake side by side with the original, and you can't see any diference.
I opened an 3886TF genuine, and I found what I was expecting. The genuine is better built and have the core perfectly aligned.
Some pictures again !
http://files.upl.silentwhisper.net/upload8/Photo-0047.jpg
http://files.upl.silentwhisper.net/upload8/Photo-0049.jpg
edit:
The most interesting is, it don't sound that bad !
Of course the genuine sounds MUCH better, but to a fake, isn't that bad ! hahahah I used a lot the fakes, no problem heheh ! Used them with 33+33v @ 8Ohms, they were not noisy and I had no problems with them. I replaced them just because I did a mistake with the supply !
The fakes really surpassed my expectations!
Anyway, the genuine improved everything, since how tight is the bass now, till the amp efficience.
Be careful, anyone here can be using fakes without know !
Hi ,
I think that it is not necessary to dissasemble ICs to determine if they are fakes. Try to push the IC hard at low drive impedance(like 2 ohms).
If it blows , or there is no spike response(high frequency "clicking") , it is probably fake.
Maybe these can be renamed cheaper ICs , like ones from ST(TDAs) ?
I can't believe they could build a factory to manufacure fake chips...
Regards,
Lukas.
I think that it is not necessary to dissasemble ICs to determine if they are fakes. Try to push the IC hard at low drive impedance(like 2 ohms).
If it blows , or there is no spike response(high frequency "clicking") , it is probably fake.
Maybe these can be renamed cheaper ICs , like ones from ST(TDAs) ?
I can't believe they could build a factory to manufacure fake chips...
Regards,
Lukas.
Sorry for grave digging but I thought the following info may be useful to people buying 3886s.
The first line should be a manufacturing code and the second line either 'LM3886T' or 'LM3886TM'. There should be nothing else marked. I've seen a chip marked 'LM3886TM +P' but can't find a reference to that extra +P in any National Semi documentation.
The device code should be the National Semi logo followed by 6 digits: die factory code (1 letter); assembly factory code (1 letter); date code (2 digits); die run code (2 letters).
eg: PM41AV means the silicone wafer was made in China in a batch designated 'AV', the body in Malaysia in 2004. JM88AP means the wafer was made in Japan in a batch designated 'AP' and the body in Malaysia in 2008.
Date and factory codes: http://www.national.com/analog/quality/marking_conventions
There are a lot of cheap 3886s on eBay with photos showing a 4 digit code - that's not a standard code!
It seems likely to me, or at least quite possible, that fake LM3886xx chips are actually LM3875xx re-marked as they have the same TA11B/TF11B packages. 3875 chips have no mute function which may be a good test method.
NB: All insulated TF11B packages, for some reason, have fractionally narrower legs than the uninsulated version.
NB: Both bold white screen printed and fine yellowish laser etched markings are valid. National moved from the former to later process so the most recently made chips will be laser etched.
The first line should be a manufacturing code and the second line either 'LM3886T' or 'LM3886TM'. There should be nothing else marked. I've seen a chip marked 'LM3886TM +P' but can't find a reference to that extra +P in any National Semi documentation.
The device code should be the National Semi logo followed by 6 digits: die factory code (1 letter); assembly factory code (1 letter); date code (2 digits); die run code (2 letters).
eg: PM41AV means the silicone wafer was made in China in a batch designated 'AV', the body in Malaysia in 2004. JM88AP means the wafer was made in Japan in a batch designated 'AP' and the body in Malaysia in 2008.
Date and factory codes: http://www.national.com/analog/quality/marking_conventions
There are a lot of cheap 3886s on eBay with photos showing a 4 digit code - that's not a standard code!
It seems likely to me, or at least quite possible, that fake LM3886xx chips are actually LM3875xx re-marked as they have the same TA11B/TF11B packages. 3875 chips have no mute function which may be a good test method.
NB: All insulated TF11B packages, for some reason, have fractionally narrower legs than the uninsulated version.
NB: Both bold white screen printed and fine yellowish laser etched markings are valid. National moved from the former to later process so the most recently made chips will be laser etched.
The +P sounds like a select part; if so it won't be in the regular documentation since it would be part of an OEM order or specification.
It's actually very common (in other area's of counterfeiting) to deliberately make a slight difference from the real product. I think that this is done to try and get some level of immunity to prosecution in areas where laws are less stringent.. It is one thing to imitate something but another thing entirely to claim to be the real thing...
By deliberately making small differences, it becomes an imitation rather than a counterfeit and it is a case of buyer beware (as the company can claim that their product clearly has a difference from the other "similar" product).
It is apparently very common in China with many consumer goods. Pakaging looks identical but they will choose a character which is almost identical but may have one additional stroke in it. To the person familiar with the brand name it will look right but the person may not realise they have been duped until after they have purchased when they find the product is of inferior quality.
Tony.
By deliberately making small differences, it becomes an imitation rather than a counterfeit and it is a case of buyer beware (as the company can claim that their product clearly has a difference from the other "similar" product).
It is apparently very common in China with many consumer goods. Pakaging looks identical but they will choose a character which is almost identical but may have one additional stroke in it. To the person familiar with the brand name it will look right but the person may not realise they have been duped until after they have purchased when they find the product is of inferior quality.
Tony.
Thanks, AndrewT.
I was about to make the same comment myself !!
http://www.diyaudio.com/forums/everything-else/183084-pictures-why-not-attach-them.html
Andy
.
I was about to make the same comment myself !!
http://www.diyaudio.com/forums/everything-else/183084-pictures-why-not-attach-them.html
Andy
.
Avoiding Fake ICs
I've been reading about these fake IC chips, and I want to make sure I am getting genuine chips for my projects. I am looking to get just a few LM1875s and LM3886s to play around with. Am I correct in assuming that the really inexpensive chips I see on E-bay that ship from China are probably fakes? I see Digikey sells them, and I think I should be able to trust that they would not sell me fakes. I am just curious if there are any other reputable vendors of these I should be aware of?
I will agree with everyone, I wish the photos earlier in this thread were posted directly to the forum, as none of the links are any good anymore. It would be interesting to see the photos.
I've been reading about these fake IC chips, and I want to make sure I am getting genuine chips for my projects. I am looking to get just a few LM1875s and LM3886s to play around with. Am I correct in assuming that the really inexpensive chips I see on E-bay that ship from China are probably fakes? I see Digikey sells them, and I think I should be able to trust that they would not sell me fakes. I am just curious if there are any other reputable vendors of these I should be aware of?
I will agree with everyone, I wish the photos earlier in this thread were posted directly to the forum, as none of the links are any good anymore. It would be interesting to see the photos.
I doubt they are fake. Too much work for such low dollar and volume items. I believe most of these guys just pass on the saving from volume purchases.
If you look at the volume pricing from some of the major US parts supplier, there are huge price breaks with big volumes. There are even better deals direct from the manufacturer.
What is cheaper than leaving the production machine running 24/7 with equipment and R&D already paid for? Who knows, the production foreman might just let the machine run an extra day longer for some bonus for himself and the employees.
If you look at the volume pricing from some of the major US parts supplier, there are huge price breaks with big volumes. There are even better deals direct from the manufacturer.
What is cheaper than leaving the production machine running 24/7 with equipment and R&D already paid for?
Who knows, the production foreman might just let the machine run an extra day longer for some bonus for himself and the employees. I believe i have some FAKE 3886TF's on hand. (Ink printed) First line; (National Symbol)PM94AG, second line; LM3886TF. I believe they are FAKE because i'm unable to identify the code printed on the IC up against with nationals DMC.
I believe some others i have a authentic, laser etched print, JM09BHE3/LM3886TF. I could be wrong, can anyone confirm this.
I believe some others i have a authentic, laser etched print, JM09BHE3/LM3886TF. I could be wrong, can anyone confirm this.
Hi,
Recently I have bought 4 LM3886T's from local electronics store.
3 of them had labels white-printed on them(Part no. JM25AQ).
1 had laser - engraved label.
Only the laser printed worked.
Looks like parts i got with no. JM25AQ are all fakes. Also their labels can be almost completely cleaned by rubbing with a solvent.
Ripped apart one.
The first is a genuine part from NSC samples program.Second - almost certainly fake. Notice the difference in die
Regards,
Lukas.
Recently I have bought 4 LM3886T's from local electronics store.
3 of them had labels white-printed on them(Part no. JM25AQ).
1 had laser - engraved label.
Only the laser printed worked.
Looks like parts i got with no. JM25AQ are all fakes. Also their labels can be almost completely cleaned by rubbing with a solvent.
Ripped apart one.
The first is a genuine part from NSC samples program.Second - almost certainly fake. Notice the difference in die
Regards,
Lukas.
Attachments
Somewhere in the Forum an ex-National employee confirmed that the die is inclined as in your first photo, because that was the only way to connect the pins to the die.
Would be interesting to know, what the second IC is. Probably some TDA, and if you knew the pin layout, you might might even build a working chip amp with it.
Will they give you your money back in the electronics store?
Would be interesting to know, what the second IC is. Probably some TDA, and if you knew the pin layout, you might might even build a working chip amp with it.
Will they give you your money back in the electronics store?
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