Can you please post the clickable links to vendors you mention in Venezuela?
Maybe that gives us an idea about how "serious" they are.
Text in the picture you posted has horrible Spanish grammar, clearly google translated and copypasted without the slightest editing, that alone hints at "no clue" seller, which is not exactly encouraging.
Can´t you straight order from Mouser?
Maybe postage is relatively expensive for "just one" since there will be a minimum charge even if you order a 10 cent resistor, but you might order a few othyer things you need, or even join needs with a friend or two, so you split Mail cost among a few.
That said, Customs typically allows "3 units of anything" tops, so you can order up to 3 x LM3886, 3 of anything else in the same order.
OR:
Plan B: order just one in Venezuela to minimize possible losses and test it.
Which means building 1 amp, applying +/-V rails, loading it with proper speaker (4 or 8 ohm) and driving it to *just* clipping.
Does it put out expected power?
Does it crack/explode/catch fire?
First with a resistive load, then with a real speaker: does it oscillate, clip weird, etc?
Real world testing.
IF good, order more; if bad try the other vendor, if both bad don´t waste time with EBay or AliBaba, go straight to Mouser, whatever it takes.
EDIT: judging from printed text and logo alone is not safe enough; I silkscreen my own PCBs and panels and can print *anything* I fancy, just get the image of the "real" one, convert it to lines/vector art using Corel Trace (there´s many similar ones) and edit/correct at will until perfect, then print ab transparency and burn a silkscreen.
Then print with 2 component epoxy ink, which when cured resists the classic "swab it with Acetone to see if it wipes away" test.
And that is Old School technology, today a faker can get a Laser engraving machine and engrave *anything* .
That´s why many above ask about "back pictures" ; actual metal and plastic casing is a better indicator .... and even so .....
Also packages often have small round 2mm "dimples" with a single letter or number molded in, that also helps ID.
But resellers will hardly show those details, for obvious reasons.
Try simulating a purchase from Mouser or straight from TI LM3886T/NOPB | Buy TI parts | TI.com
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They are taking a lot of trouble for a $2 part, which is what the maker will get.
And why the factory does not destroy off spec rejection I cannot understand.
See if the real ones are in stock, they are out here in India.
And why the factory does not destroy off spec rejection I cannot understand.
See if the real ones are in stock, they are out here in India.
They make fake TIP41 and even fake TO-92. They even make fake regulators that "work" but are only 100 mA or 500 mA when they are supposed to be 1A or 1.5A.
Usually the fake semiconductor die are different die from a different factory (not off spec rejects).
They even make fake NE5532 and TL072 which are often LM358 or if you are lucky a cheap 4558 clone.
Usually the fake semiconductor die are different die from a different factory (not off spec rejects).
They even make fake NE5532 and TL072 which are often LM358 or if you are lucky a cheap 4558 clone.
Here I get branded knock offs, they work at not too high ratings, and durable.
1875, 4440, 2030, 2050, STK 4141, and so on, long out of production at the original factories.
TI TL072 is 15 Rupees, about 20 US cents, Kia 4558 was 20, NJM 5532 was 40 IIRC.
ST 741 were 5 each, and genuine 358 (ST ) were 10...
ST TIP41 were 40, fake were about 30, generic TO92 were just 2 each.
4007 go for 0.30 each in 1000 packs, about 0.50 retail.
I wonder how profitable the silicon industry is, the bill of material cost will not differ much in genuine and fake.
1875, 4440, 2030, 2050, STK 4141, and so on, long out of production at the original factories.
TI TL072 is 15 Rupees, about 20 US cents, Kia 4558 was 20, NJM 5532 was 40 IIRC.
ST 741 were 5 each, and genuine 358 (ST ) were 10...
ST TIP41 were 40, fake were about 30, generic TO92 were just 2 each.
4007 go for 0.30 each in 1000 packs, about 0.50 retail.
I wonder how profitable the silicon industry is, the bill of material cost will not differ much in genuine and fake.
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This is the link where I got the pictures from: https://articulo.mercadolibre.com.v...cking_id=dcbe6cec-8785-46cf-9d3d-4ecc88c4bdfe
And this is the other one I mentioned: https://articulo.mercadolibre.com.v...cking_id=44db2829-5344-4203-9d13-f9b2094749df
These two are the only local online stores that sell it and accept Paypal, I would still need to check phisical stores to see what they got but I doubt they accept Paypal (Also Mouser seems to be out of stock)
1) when quoting please edit message as I am doing now, no need to repeat it IN FULL when it´s just above, only leave *one* text line to identify it.
2) Mercado Libre sellers can be offering *anything*, but both have 100% good feedback/reputation, so they "should" be honest.
I would buy fom either of them , if anything the second (U$13) looks better: 11 years selling, >6000 completed sales, apparently ral pictre (the other one uses generic ones).
Buy *one* and try it, you are not risking much, in any case you have no other option.
Build it *carefully*, use a series lamp bulb limiter as protection, to avoid assembly errors and never knowing whose responsibility it is.
Or at least use a 100 ohm resistor in series with each +/-V rail from power supply, no speaker load, worst case they willact like current limiters and improvised cheap fuses.
IF all voltages look normal, specially 0Vdc at speaker out, replace them by 10 ohm resistors, connect speaker, and play it very low (a few milliwatts, earphone volume).
If all fine,connect amp straight to supply and test how it sounds.
Which PCB will you use?
Stiore bought? Homemade?
Show a picture.
PS: you can also test amp with a lower voltage supply, say 12+12V or 15+15
IT will work, only at reduced power out.
IF it works perfectly with low voltage supply but explodes with say, +/-28V or whatever datasheet recommends, it CONFIRMS you built it well, but part is FAKE. 😡
Post results either way.
Areyou far away from Caracas?
Maybe you can go there and buy in person.
Self quoting:
With datasheet suggested +/-22V supplies they overheat even idle, distort at low power and heat up even more with any load, eventually explode cracking plastic case, a mess.
Obviously I was very unhappy with that, I had paid them full price trusting seller, not only lost that money but also my new amps for which I had spent time and money refining circuit, designig and making PCBs, making chassis, silkscreening front panels, etc. , a total waste.
BUT they work very well with +/- 12-14V rails, which is TDA2030 spec supply, so obvious suspicion is that they are "good" second or third tier supplier (not ST as marked) , which are still available in quantity and for a good price, *labelled* as unavailable (so expensive) TDA2050
So at least it was not a total loss, I made a far simpler cheaper 15W amp and at least I am moving them out the door.
That´s why I suggest testing yours with lower supply voltage first, if available (a simple 12+12VAC transformer, bridge, and 2 x 2200x25V caps).
I bought 50 TDA2050 from a "serious" seller, supposedly out of the last "true" batch made, to make 50 25W Guitar amps.
With datasheet suggested +/-22V supplies they overheat even idle, distort at low power and heat up even more with any load, eventually explode cracking plastic case, a mess.
Obviously I was very unhappy with that, I had paid them full price trusting seller, not only lost that money but also my new amps for which I had spent time and money refining circuit, designig and making PCBs, making chassis, silkscreening front panels, etc. , a total waste.
BUT they work very well with +/- 12-14V rails, which is TDA2030 spec supply, so obvious suspicion is that they are "good" second or third tier supplier (not ST as marked) , which are still available in quantity and for a good price, *labelled* as unavailable (so expensive) TDA2050
So at least it was not a total loss, I made a far simpler cheaper 15W amp and at least I am moving them out the door.
That´s why I suggest testing yours with lower supply voltage first, if available (a simple 12+12VAC transformer, bridge, and 2 x 2200x25V caps).
Well, same here.. from Bangalore local market (SP Road). Unfortunately, even I got them just like that (no anti-ESD), what to do, good luck to myself! Maybe they'll work.
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JK_Parts is a seller from China ... many products are cheap copies . Could work like the original or with inferior performance most of times 😀
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Looks authentic, i'm sure will work fine. I bought total eight chip for a big stereo amp(yet to finish) & later two more for one my friends. Sounds fantastic and inbuilt SPIKE protection works ruthlessly when needed!
Don't think too much about esd blah blah blah...
nirupambhowmick said:
Not at all my friend, quite unfortunately, charge accumulation on insulators (including fingertips) and the damage that can result are both very true. It's best not to buy anything expensive (memory etc.) if it comes without the anti-ESD packing.
Coming to authenticity, I also happen to have a few engineering samples from National lying around somewhere that I could compare these to, when I find them.
EDIT: Found them, they look the same..
Cheers.
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Yes ESD is real & 'serious,' i'm not denying that but believe me not always!(except logic, memory, small signal fets). Recently i bought 30× genuine Philips bc556 transistor from a shop (near my nest) without esd protection but their hfe mesure very consistent! better than ever 😉 & couple of months ago i bought 100p(min quantity) Fairchild bc546 from a international seller(with esd bag) but hfe mesure is not very consistent like those NOS Philips transistors without esd protection 😛
Anyway i find india a nice place for hobbyists if not great. I have a great stock of components for various future audio projects and don't need anymore 😉😀
Anyway i find india a nice place for hobbyists if not great. I have a great stock of components for various future audio projects and don't need anymore 😉😀
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What the listing photo looks like is irrelevant. The fakers usually have photos of genuine and then ship you fake.
I second that. I've some real Lm1875 recently bought from rs & can prove it now. I believe it's a tribute from Texas instrument to National semiconductor. Anyway i like NS logo more 🙂
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This is my Fake LM3886
When this chip failed it ran 20 plus volts DC through my speaker, it ruined three voice coils.
When I rebuilt the Amp I added Tom's Guardian 686, and all Mouser parts.
When this chip failed it ran 20 plus volts DC through my speaker, it ruined three voice coils.
When I rebuilt the Amp I added Tom's Guardian 686, and all Mouser parts.
Attachments
Individual bipolar transistors are not all that susceptible to ESD damage - typically takes more than a 2KV ESD strike to even do anything you would notice. Some parts get upset with as little as 250, big power transistors over 8kV (the limit of testing). ESD events are of limited *energy*, and even a TO92 transistor is a big die with a good heat dissipation capability compared to an input pin on a CMOS IC.
The LM3886, being a bipolar IC and a complete audio amplifier, I would expect it to be at least as good as it’s input stage for ESD robustness. The power supply terminals will take a lot, speaker out just as much. Input stage is probably *rated* to 2KV HBM, and could take more if protection diodes are present.
