i built 2 identical circuits using this chip, and they behave vastly different. The one that was built using chips that were suspiciously cheap (this guy was selling em little under $2 a piece. I just had to bite the bullet), and this amp not only runs wayyy too cool but sounds tinny (read: thin, not enough drive) and it was much harder to tame. I had to up the gain to 30 to kill the oscillation where as the other amp works fine at gain of 10 and sounds better.
Now the chips look completely identical. I even cracked open the suspicious ones and their crystal was the size its suppose to be. Maybe the one thats running hotter is the fake one and lm1875s are suppose to run very cool?
I plan on going into the town tomorrow, pick up some different lm1875s and also tda2030s to compare their behavior.
What are your thoughts?
Will post pics upon request. Thank you.
Now the chips look completely identical. I even cracked open the suspicious ones and their crystal was the size its suppose to be. Maybe the one thats running hotter is the fake one and lm1875s are suppose to run very cool?
I plan on going into the town tomorrow, pick up some different lm1875s and also tda2030s to compare their behavior.
What are your thoughts?
Will post pics upon request. Thank you.
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Thoughts... measure the quiescent current of each chip and look and also see if any obvious distortion is present when viewed on a scope with a 10kHz test signal.
Identical circuits but physically two different amps. I would swap the chips between the two boards as 100% confirmation something with the chip is amiss.
The LM1875 data sheets suggests around 70ma quiescent and the TDA 2030 a little lower at typically 50 ma. In practice both would feel pretty similar heat wise with those currents.
Identical circuits but physically two different amps. I would swap the chips between the two boards as 100% confirmation something with the chip is amiss.
The LM1875 data sheets suggests around 70ma quiescent and the TDA 2030 a little lower at typically 50 ma. In practice both would feel pretty similar heat wise with those currents.
Sadly i dont have an oscilloscope or a microscrope. The only data i have to go by is this website, which according to it the 'fake' chip i have should be genuine because of the die size and the package appearance.
Which makes me wonder if the website is wrong or what i have is just different kind of counterfeit.
Checking the prices for the chip theyre all higher than what i paid for even at their bulk prices except for one brand called HG SEMI. Its a chinese brand and their price is 80 cents a piece. Im thinking maybe this is the one im dealing with after its been rebranded as TI
Which makes me wonder if the website is wrong or what i have is just different kind of counterfeit.
Checking the prices for the chip theyre all higher than what i paid for even at their bulk prices except for one brand called HG SEMI. Its a chinese brand and their price is 80 cents a piece. Im thinking maybe this is the one im dealing with after its been rebranded as TI
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^^^^^^^ THAT.
Any decent speaker is worth more than 5 or 6 bucks so your "savings" can become very expensive.
Don´t even waste time testing the bad ones, you already know they are.
FWIW I was also bitten, in this case with 100 TDA2050, which I bought at a local supplier, guaranteed to be from the last batch made
and paid full price for them.
When subject to +/- 20V rails (perfectly fine for 2050) they overheat even without load or signal, clear indication of internal semiconductors breaking down.
They supply dirty fuzzy audio and after a couple minutes they self turn off.
Now they are perfectly happy with +/- 14V , work perfect, clean sound ... which makes me think they are actual TDA2030 or equivalent dies.
So it´s not a total loss, but I couldn´t make the 25W guitar amplifier I was about to launch, and I am not interested in 15W ones, where the market is *crowded*, and importing LM1875 (not available here) becomes expensive for the target audience I expect.
Just buy the good ones ... while they are still available.
Any decent speaker is worth more than 5 or 6 bucks so your "savings" can become very expensive.
Don´t even waste time testing the bad ones, you already know they are.
FWIW I was also bitten, in this case with 100 TDA2050, which I bought at a local supplier, guaranteed to be from the last batch made
and paid full price for them.When subject to +/- 20V rails (perfectly fine for 2050) they overheat even without load or signal, clear indication of internal semiconductors breaking down.
They supply dirty fuzzy audio and after a couple minutes they self turn off.
Now they are perfectly happy with +/- 14V , work perfect, clean sound ... which makes me think they are actual TDA2030 or equivalent dies.
So it´s not a total loss, but I couldn´t make the 25W guitar amplifier I was about to launch, and I am not interested in 15W ones, where the market is *crowded*, and importing LM1875 (not available here) becomes expensive for the target audience I expect.
Just buy the good ones ... while they are still available.
I haven't seen a chip by Burr-Brown, Unitrode, National, or any other company that TI has acquired over the years, with a TI logo. They all have the Burr-Brown, Unitrode, National, etc. logos.
If your LM1875 has a TI logo, it's a guaranteed fake.
You can buy the LM1875 directly from TI. They charge a flat shipping fee of $6.99 USD. Why bother with fakes?
Tom
If your LM1875 has a TI logo, it's a guaranteed fake.
You can buy the LM1875 directly from TI. They charge a flat shipping fee of $6.99 USD. Why bother with fakes?
Tom
Chinese LM1875 here (and TDA2030, also Chinese) worked OK in a Philips set whose NEC UPC1238 were giving out 4 volts DC
Replacing them solved the problem, they were having a M-W logo
Supply was 0-14-28 volts, the 14 was for pre amps and radio
Cost me 15 Rupees - 20 cents each
Genuine TDA 2050 goes for about 60 Rupees here in India
TDA 2030A also said to be genuine are about 50 Rupees.
The set runs Sony speakers, not much difference in sound on the outputs on different channels.
I put one 1875 and one 2030 in the same set.
Replacing them solved the problem, they were having a M-W logo
Supply was 0-14-28 volts, the 14 was for pre amps and radio
Cost me 15 Rupees - 20 cents each
Genuine TDA 2050 goes for about 60 Rupees here in India
TDA 2030A also said to be genuine are about 50 Rupees.
The set runs Sony speakers, not much difference in sound on the outputs on different channels.
I put one 1875 and one 2030 in the same set.
The thing is that the shop owner is a distant cousin, he tells me straight out what it is.
Possibly a higher grade version, as you say.
But there a 1875 would also work, in place of a 2050
And yes, in Chinese chips also they are marked by the makers, and some are considered to be of consistent quality...branded copies of the following :
4440, 1875, 6283, 1619 (FM radio) are commonly used here, and they work okay.
Amplifiers are sold here with a USB/FM module, which can read USB and SD memory cards, recieves FM, and can connect and aux input too.
With remote, module is 95 Rupees....$1.20, no remote gets you 20 cents discount.
Amplifiers are :
4440 based, 650 Rs. onwards
2N3055 based, 1200 onwards
STK 4141 based, 1400 onwards
MOSFET based 4500 onwards, those use 8010 or larger transistors.
I just assembled a 2.1 kit ...3 x 1875 where the populated PCB was 150
Transformer, speakers, pots etc. were all extra...awaiting a housing.
4440 kits start from 220 onwards, you can see online...some are offered with Keltron capacitors which are much better than most Chinese ones, they got the technology from Sprague.
Frankly, why pay for a said to be genuine part when you can get a okay copy for loose change?
What to do when you have a blown chip on an otherwise okay set?
Then you either scrap it, or rework it using a copied chip or another chip.
I have a Sony set with a STK 403-100, going to put 7294 or 93, major work. The 403-100 is not available.
Possibly a higher grade version, as you say.
But there a 1875 would also work, in place of a 2050
And yes, in Chinese chips also they are marked by the makers, and some are considered to be of consistent quality...branded copies of the following :
4440, 1875, 6283, 1619 (FM radio) are commonly used here, and they work okay.
Amplifiers are sold here with a USB/FM module, which can read USB and SD memory cards, recieves FM, and can connect and aux input too.
With remote, module is 95 Rupees....$1.20, no remote gets you 20 cents discount.
Amplifiers are :
4440 based, 650 Rs. onwards
2N3055 based, 1200 onwards
STK 4141 based, 1400 onwards
MOSFET based 4500 onwards, those use 8010 or larger transistors.
I just assembled a 2.1 kit ...3 x 1875 where the populated PCB was 150
Transformer, speakers, pots etc. were all extra...awaiting a housing.
4440 kits start from 220 onwards, you can see online...some are offered with Keltron capacitors which are much better than most Chinese ones, they got the technology from Sprague.
Frankly, why pay for a said to be genuine part when you can get a okay copy for loose change?
What to do when you have a blown chip on an otherwise okay set?
Then you either scrap it, or rework it using a copied chip or another chip.
I have a Sony set with a STK 403-100, going to put 7294 or 93, major work. The 403-100 is not available.
“Frankly, why pay for a said to be genuine part when you can get a okay copy for loose change?”
I completely disagree with this way of thinking, that’s the reason there are so many fakes in the world, not only chips and electronic parts , but clothes, shoes , accessories , fashion stuff, brands etc.
I completely disagree with this way of thinking, that’s the reason there are so many fakes in the world, not only chips and electronic parts , but clothes, shoes , accessories , fashion stuff, brands etc.
Yup, SG Singapore. The bent leads may require straightening out for use on the MiniRef, or maybe it's just perfect for a flat (not perpendicular) heatsink configuration.
My relative sells about 300 amplifier boards and FM modules a month, about 1000 dish antenna sets too.
One chip is kid stuff...I repair things for myself or family, I am not a repair man.
This is just a hobby for me.
So if he tells me it is genuine or good fake or bad fake, it is because we are family. Not because he is going to make 20 cents in a deal worth a few dollars.
He has been trading components for more than 25 years. Sells things from tools like meters and soldering irons to LED modules apart from satellite recievers.
As for the 2050, he did say 2030A were better.
My point was that if I get a 2050 marked ST or Philips or NXP, might be fake.
Better put a known copy of good quality.
And ST, Maxim and others have taken over lines from other makers like Philips. So as they did not develop the chip, they are generic makers of good quality chips rather than designers...TDA came from Philips if I remember correctly..
Philips themselves put a lot of their semiconductor business under NXP.
If it works reliably, and done myself, I am satisfied.
Too many times bad workmanship here, once colours reversed on a TV because the guy put a NPN instead of PNP transistor!
And cosmetic problems too...scratches and all.
I bought my first soldering iron in 1978 in 8th grade, been doing my minor repairs since then.
By education I am a graduate engineer. So I am being practical rather than overly fussy about this issue here.
Again, what happens if you need to put a chip no longer made by the original maker, but Chinese available? Like the 1619 FM tuner chip, Sony dies not make them any more.
One chip is kid stuff...I repair things for myself or family, I am not a repair man.
This is just a hobby for me.
So if he tells me it is genuine or good fake or bad fake, it is because we are family. Not because he is going to make 20 cents in a deal worth a few dollars.
He has been trading components for more than 25 years. Sells things from tools like meters and soldering irons to LED modules apart from satellite recievers.
As for the 2050, he did say 2030A were better.
My point was that if I get a 2050 marked ST or Philips or NXP, might be fake.
Better put a known copy of good quality.
And ST, Maxim and others have taken over lines from other makers like Philips. So as they did not develop the chip, they are generic makers of good quality chips rather than designers...TDA came from Philips if I remember correctly..
Philips themselves put a lot of their semiconductor business under NXP.
If it works reliably, and done myself, I am satisfied.
Too many times bad workmanship here, once colours reversed on a TV because the guy put a NPN instead of PNP transistor!
And cosmetic problems too...scratches and all.
I bought my first soldering iron in 1978 in 8th grade, been doing my minor repairs since then.
By education I am a graduate engineer. So I am being practical rather than overly fussy about this issue here.
Again, what happens if you need to put a chip no longer made by the original maker, but Chinese available? Like the 1619 FM tuner chip, Sony dies not make them any more.
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The TDA 2050 above mentioned have a code starting with 88
Possibly 1988...new old stock from production in Singapore.
So some are still out there in the wild.
Don't knock it till you get it in your hand.
And in most cases, 1875 is a direct replacement, so I would prefer the easily available one rather than the one shipped from far away which will arrive after a month.
Possibly 1988...new old stock from production in Singapore.
So some are still out there in the wild.
Don't knock it till you get it in your hand.
And in most cases, 1875 is a direct replacement, so I would prefer the easily available one rather than the one shipped from far away which will arrive after a month.
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