I recently got a batch of LM386s from two different ebay sellers and ALL of them are crap... they don't work like they're supposed to - all I get is loud squealing, very loud weird noises and farting sounding oscillation if I do even get any signal going thru them. I'm beginning to believe these are counterfeits or factory rejects that somehow got into the public domain (Jameco). If I put the LM386s I got 12-14 years ago in the same circuit and they work just fine.
Has anyone else had this experience? At this point all I can say is WTF?
So, you ordered them from Jameco, or did you mean Jameco tossed them and someone resold them?
I imagine in each of my chip drawers there is at least one chip that I pulled from a perfed circuit that was misbehaving, and saved it because I didn't know for sure that the chip was bad. Removal was just an incidental part of troubleshooting.
I probably should have taken my white paint-pen and stuck a dot on the underside of each of them, just to be able to identify them later.
Quote from: Mark Hammer on May 14, 2018, 10:39:36 AM
So, you ordered them from Jameco, or did you mean Jameco tossed them and someone resold them?
I imagine in each of my chip drawers there is at least one chip that I pulled from a perfed circuit that was misbehaving, and saved it because I didn't know for sure that the chip was bad. Removal was just an incidental part of troubleshooting.
I probably should have taken my white paint-pen and stuck a dot on the underside of each of them, just to be able to identify them later.
No, one of the sellers was Jameco. I bought 10 from them and five from a different seller and ALL 15 of them are crap.
I work for an entity that purchases A LOT of electronics assemblies and parts.
I have been to 3 lectures THIS YEAR regarding the rampant problem with counterfeiting.
Catch my drift? :-\
It's bad!
Quote from: Govmnt_Lacky on May 14, 2018, 12:09:13 PM
I work for an entity that purchases A LOT of electronics assemblies and parts.
I have been to 3 lectures THIS YEAR regarding the rampant problem with counterfeiting.
Catch my drift? :-\
It's bad!
Argh. I was so mad for the last couple of weeks.... built the same circuit twice thinking it was my fault for all the weirdness, feeling like an idiot that can't do anything right and the whole time it was the damn fake or whatever the hell they are chips! Ridiculous (revolting, sad, infuriating, pathetic, annoying, disgusting) what people will do for a few bucks.
Yes it's sad mate.
Why don't you open a case with Ebay and get your money back at the least.
Chances are they will support you.
Quote from: Kipper4 on May 14, 2018, 03:24:21 PM
Yes it's sad mate.
Why don't you open a case with Ebay and get your money back at the least.
Chances are they will support you.
Not a bad idea.... but I have enough stress in every day life. I don't need to get shingles in my eye again, this time it will probably blind me in that eye. Anyway, this topic for sure is on my radar now!
QuoteYes it's sad mate.
Why don't you open a case with Ebay and get your money back at the least.
Chances are they will support you.
If no one says anything they will keep selling.
Counterfeits are definitely a problem that people who manage electronics supply chains are concerned about. And it seems to me that counterfeits have become a problem in DIY, especially with end-of-life or rare-ish devices: BBDs, CA3080, through-hole JFETs. It seems a little weird to counterfeit a chip as common as the LM386, though. It also is strange to me that one would get problem ICs from Jameco; ebay is buyer-beware, but Jameco is a large supplier. I would at least send them an email and ask if they've had any other reports of problems.
Quotet also is strange to me that one would get problem ICs from Jameco; ebay is buyer-beware, but Jameco is a large supplier.
That's why it should be reported. You don't know where it is in the chain unless it is investigated. It could a dodgy supplier for Jameco or it could be dodgy employees in the warehouse or in shipping. I remember a story were a genuine parts were swapped with fakes when the flight passed through China. Everything looked legit except the parts! It takes organization, probably at the source, to pull something like that.
hi Paul,
just out of curiosity: do they work in op-amp circuits? just asking as there are only a handful of 8-pin power amp IC's i know of and i don't think they're pin-compatible, so maybe they're just a bunch of crap op-amps.
i know there are TDA* chips which offer better performance than the 386, but is there anything cheaper on the (legit) market?
QuoteNo, one of the sellers was Jameco. I bought 10 from them and five from a different seller and ALL 15 of them are crap.
Make sure your circuit meets all the requirements of the datasheet, like the Zobel network. If it doesn't, one day, perhaps today, the circuit will misbehave even though it didn't before. Moreover when it does misbehave like this it is likely to do the same on chips of the same batch.
Bypass caps on the supply and issue with grounding are also possible conditions which cause oscillation and the symptoms you see. If not enforced in the datasheet these are upto the designer so it's hard to determine the blame unless you try it on a 100% clean layout.
I found this,
https://hackaday.com/2017/07/15/lets-play-spot-the-fake-mosfet/
Go half-way down
" Wolf says:
July 15, 2017 at 9:41 am "
Quote from: Rob Strand on May 14, 2018, 08:25:04 PM
QuoteNo, one of the sellers was Jameco. I bought 10 from them and five from a different seller and ALL 15 of them are crap.
Make sure your circuit meets all the requirements of the datasheet, like the Zobel network. If it doesn't, one day, perhaps today, the circuit will misbehave even though it didn't before. Moreover when it does misbehave like this it is likely to do the same on chips of the same batch.
Bypass caps on the supply and issue with grounding are also possible conditions which cause oscillation and the symptoms you see. If not enforced in the datasheet these are up to the designer so it's hard to determine the blame unless you try it on a 100% clean layout.
Two different builds, same circuit, same results. If I use my LM386s from 12-14 years ago it works just fine. When I put these "new" ones in the circuit they become completely unusable. So that leads me to believe that either the LM386s are fakes, factory rejects, or they have significantly changed the internals of the chip so that it no longer works in the circuit as designed. The circuit follows the data sheet and it's running on 9V. The data sheet seems to be the same as it was say 10 years ago. If the chips were to spec I should be having none of these problems.
Quote from: MrStab on May 14, 2018, 08:23:18 PM
hi Paul,
just out of curiosity: do they work in op-amp circuits? just asking as there are only a handful of 8-pin power amp IC's i know of and i don't think they're pin-compatible, so maybe they're just a bunch of crap op-amps.
i know there are TDA* chips which offer better performance than the 386, but is there anything cheaper on the (legit) market?
I had a thought that maybe they're opamps marked as LM386s but I haven't tested that theory.
Quote from: reddesert on May 14, 2018, 07:03:03 PM
Counterfeits are definitely a problem that people who manage electronics supply chains are concerned about. And it seems to me that counterfeits have become a problem in DIY, especially with end-of-life or rare-ish devices: BBDs, CA3080, through-hole JFETs. It seems a little weird to counterfeit a chip as common as the LM386, though.
I'm aware of the counterfeiting with BBDs, etc. Some people seem to think that the LM386s are now obsolete and they will be going away. Or at least maybe that's the belief in counterfieitland? I dunno.
Paul, you should contact Jameco directly. Being a large and reputable business, they would want to know if there is a problem with any of the parts they sell. Hopefully, they would send you some real 386s.
Since you bought from Jameco through ebay, do you recall where it said the items would be shipped from?
Quote from: Electron Tornado on May 15, 2018, 10:44:55 AM
Paul, you should contact Jameco directly. Being a large and reputable business, they would want to know if there is a problem with any of the parts they sell. Hopefully, they would send you some real 386s.
Since you bought from Jameco through ebay, do you recall where it said the items would be shipped from?
I have the envelope it was mailed in, but I'm at work right now. Here is a link to the ebay page: https://www.ebay.com/itm/Texas-Instruments-LM386N-1-NOPB-Audio-Amp-Single-Speaker-1-Channel-Mono-0-10-pcs/112229787423?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649
conspiracy theory: Jameco banks on the increased difficulty of raising complaints (and subsequently less harm to reputation) facilitated by eBay, and gets rid of known-counterfeit goods there?
they could at least get one decent image of a generic DIP8 IC. i know it's superficial, but i've rejected sellers based on the half-assedness of their images. you'd look past that when it's a brand everyone recognises like Jameco, though.
Paul... if you are in a bind and need some LM386s, let me know. I am 99% sure I have some around with no plans for use.
(Not sure if they are -1 or -4 though)
I was going to ask "Which 386 is supposed to be?". LM386-4 is discontinued (although only recently), and because of it's voltage/power range has been the most popular in 9v projects. Whether the -1 to -3 variants work in your particular project I can't say. I've only ever used the -4. Of course, fakes could be any kind of device in the same package.
Since the LM386-4 is supposed to be gone the way of the Diplodocus, there is still the JRC version NJM386BD which is a -4 and still in production. Hopefully less chance of fakes if you look for the NJM parts instead.
Digi-key has only 10,411 of the TI LM386N-4 in stock today. Order now, supplies are limited!
AFAIK the difference between LM386N-4 and LM386N-1 is that the -4 has higher output power.
I bought some LM386 from Tayda within the past year (I don't remember what kind, and they sell both National Semi and a knockoff), and they worked.
I got a package of LM386M from China. Worked fine for things like my actual audio probe, which have an signal generator and a little amp with speaker in a battery sized board. But I tried an overdrive, and got low gain. I tried an guitar amp, and got loads of oscillation. They work, but surely not as they should.
I general to everybody, buy from reputible sources and all should be good, also always check the latest datasheet for changes just in case of changes. An LM386 form a a good source is only 0.63 UK pounds here in the UK (50 cents USA) There are likely no shortages on most parts that you need to find so why risk buying unknown shite. I have never heard of Jameco but having just checked their website it does look like a proper supplier so they should be good. Remember with ebay you take your own chances and if they are crap then you only have yourself to blame really for trying to save 1cent or so on a part. I'm not trying to sound bad but buy from a truster dealer. Maybe look into Mouser if your in the USA.
Quote from: anotherjim on May 15, 2018, 01:39:41 PM
the way of the Diplodocus
those have been discontinued, too?!!! man, this is f***ing bulls**t!
Quote from: anotherjim on May 15, 2018, 01:39:41 PM
Since the LM386-4 is supposed to be gone the way of the Diplodocus, there is still the JRC version NJM386BD which is a -4 and still in production. Hopefully less chance of fakes if you look for the NJM parts instead.
Looking on the Texas Instrument website I can't see any reference to any LM386 being discontinued at all. It's late and I may have missed it but nah ! I can't see it.
> I have never heard of Jameco but...
Jameco has been a force in US parts since the 1970s (https://en.wikipedia.org/wiki/Jameco_Electronics). For a while they distributed "James-Paks", single parts in bubble-packs on a rack which many small parts-stores put out for impulse purchases. Their paper catalogs were a treat of odd-lots of surplus goods, particularly power supplies. My first IBM PC was a Jameco kit.
I have no idea how they stay alive in the face of DigiKey and Mouser (who started in that same decade).
Quote from: Govmnt_Lacky on May 15, 2018, 12:10:31 PM
Paul... if you are in a bind and need some LM386s, let me know. I am 99% sure I have some around with no plans for use.
(Not sure if they are -1 or -4 though)
I need four of them if you want to make good on that offer.
Quote from: Ice-9 on May 15, 2018, 07:33:10 PM
Remember with ebay you take your own chances and if they are crap then you only have yourself to blame really for trying to save 1cent or so on a part. I'm not trying to sound bad but buy from a truster dealer. Maybe look into Mouser if your in the USA.
Yes, and until I got the LM386s I've never had a negative experience. I guess times have changed, for the worse. >:(
Some confusion. TI website only lists LM386M-1 and LM386MX-1, both only available in an smd flat pack package. However, the current datasheet pdf continues to list LM386N-4 PDIP as "Active" in addition to some other varieties.
That said, some suppliers have definitely removed the LM386N-4 from their lists and, where able, replaced with the NJM part.