OPA2604 - can these be real?

[Michael Tibes]

I found this offer for opa2604s on ebay, for a very good price if they were real:

http://www.ebay.de/itm/20-OPA2604AP-OPA2604-DUAL-FET-INPUT-OP-AMPLIFIER-ICS-/280762080788?pt=LH_DefaultDomain_0&hash=item415eb95e14

Does anyone know how to determine whether these are fakes - or are they obvious fakes?

Michael

 

[detonator]

The price is for all 20 pieces. Divide and it's 2.14 per piece

 

[sahib]

Half the price than RS. However, you can probably get it greatly cheaper in US than you would get it in Europe.

Over the years I learned not to automatically suspect for the things shipped from China but this is e-bay. Is it worth taking the risk for the extra few Euros? In my view for diy needs yes. The guy is offering 30 days guarantee which is a sufficient time to check their performance.

 

[Michael Tibes]

Half the price than RS. However, you can probably get it greatly cheaper in US than you would get it in Europe.

Over the years I learned not to automatically suspect for the things shipped from China but this is e-bay. Is it worth taking the risk for the extra few Euros? In my view for diy needs yes. The guy is offering 30 days guarantee which is a sufficient time to check their performance.

Yes, but the shipping cost from Germany back to China are so high, that I'd probably just scrap the stuff anyway if it sucked... It would just be interesting to see if anyone here screems yes or no out of experience or better knowledge.

These dealers seem to be very aware of their ebay reputation. I believe they wouldn't be too happy about bad remarks, so I hope it should be safe to buy it.

Michael

 

[Biasrocks]

I received some bad OPA2604's/604's from Chinese sellers.

I spent a few extra hours troubleshooting before finding them.

Not really worth the $10 I saved.

Regards,
Mark

 

[s2udio]

As sahib said

The seller gives a 30day warranty and has good feedback ...

I dont see how you could go wrong,

Personally I have had a higher % of duff components from non Ebay traders .

Not everything that comes from china is useless or fake !

 

[MeToo2]

I found this offer for opa2604s on ebay, for a very good price if they were real:

http://www.ebay.de/itm/20-OPA2604AP-OPA2604-DUAL-FET-INPUT-OP-AMPLIFIER-ICS-/280762080788?pt=LH_DefaultDomain_0&hash=item415eb95e14

Does anyone know how to determine whether these are fakes - or are they obvious fakes?

Michael

I've had some really great quality cables made in China that were obviously not genuine, but were fantastic for testing and mucking about. I've also had some garbage that just didn't work at all.

Problem with an opamp is that they could have virtually any circuit inside, so even if they were functional it'd be hard to tell if they were genuine OPA2604 without freezing them, sawing them open, and putting them under a microscope (and yes people do that in the industry, sometimes just to see what competitors are doing).

I tend to view Chinese stuff (or indeed any online stuff) as a gamble. Sometimes it pays off. Sometimes it doesn't.

Difficult to get outdated chips and linear ICs like a dual FET for non-critical kit e.g. a cheap DIY synth?
Yes, that's certainly worth a try in my opinion, if only to keep costs down.
Anyway, you can normally rejig the circuit just to use a FET op amp buffer instead of a discrete dual FET if it doesn't work out.

Difficult to get components for repairing an important piece of kit like a genuine vintage analogue synth?
Probably not. Why would the Chinese have stocks of surplus 1970's or even 1980's US components?
Taiwan maybe, but mainland China? Could also affect the resale value of your gear.

Easy to get components for an important new piece of kit that are just a few euros cheaper?
No. Never.

OPA2604 falls into that last category for me.

Why install an OPA2604 (that may be fake) when you could use a cheaper genuine op amp like an TL072 or NE5532? If the answer "is I really don't want a TL072 or NE5532", why take the risk? Because that might be exactly what you're actually buying.

eBay price = ±34 Euros Farnell price for 20 OPA 2604 = ±80 Euros. 20 TL072 only cost 8 euros. Mouser ±63 or 75 euros if you get caught for VAT. 20 TL072 will also only cost 8 euros.

So you're saving maybe 46 euros max on genuine OPA2604's. If you actually need less than exactly 20 chips, the difference also reduces.

 

[Biasrocks]

The seller gives a 30day warranty and has good feedback ...

I dont see how you could go wrong,

That's cool.

I purchased my OPA's and didn't end up using them for 6 months it was impossible to leave negative feedback even if I could remember who I purchased them from.

Best of luck.

Regards,
Mark

 

[keefaz]

it'd be hard to tell if they were genuine OPA2604 without freezing them

Maybe some basic hint like the current consumption ? opa2604 should draw 10-12ma, while other opamp like TL072 or NE5532 use less current

 

[MeToo2]

it'd be hard to tell if they were genuine OPA2604 without freezing them

Maybe some basic hint like the current consumption ? opa2604 should draw 10-12ma, while other opamp like TL072 or NE5532 use less current

Sure. And a TL072 has far less bandwidth too. And an NE5532 is bipolar. These chips could be anything. They could be a completely non-functional fake empty packages with some nice printing. They could be rebranded 741's with a BB logo and part number on them. They could be very good functional copies that have similar characteristics, but which just aren't quite as good in some parameters like having a lower slew rate, because the fab used a slightly different wafer process with the same mask design. Or they may exhibit slightly lower bandwidth. Or higher power consumption. Or they might have poor quality packaging pins that bend and snap off. Or they might oscillate under certain circumstances, but not others. Or they may fail under temperature stress. Or they're non ROHS compliant. Or anything else. They could even be the "100% genuine article new old stock."

But unless someone on the board is prepared to order a big batch and test all the individual specs against the manufacturer's data sheet, I just don't see how the financial benefit/ time cost would stack up for me to justify taking a risk on this particular component for my particular projects. Others may want to take that risk.

Shenzhen is wild west. I know companies that protect their intellectual property for chip designs from their own Chinese staff.

The way I look at it: If you want a cheap op amp, buy a cheap op amp. If you want a great op amp, buy a great op amp.


BTW I found the following Japanese site via google. http://yoruniha.blog48.fc2.com/blog-date-201109.html Shove this text through google translate and it is complaining that the date code 8BW107B on this op amp (which is the same on the eBay auction) was a fake. The eBay seller may not even realize and may think he is acting in good faith.

 

[s2udio]

Looks like chinese paranoia setting in...........?
???

 

[MeToo2]

Looks like chinese paranoia setting in...........?
???

Not at all. I've worked there and seen it with my own eyes. China can produce truly great products comparable to any other country. And they can produce great fakes too. If you want to take the risk that's your decision.

 

[s2udio]

And they can produce great fakes too.

Never heard of a fake anything being called "Great"

 

[MeToo2]

And they can produce great fakes too.

Never heard of a fake anything being called "Great"

Don't get confused between originality and quality. They're separate things. The fake may be so good that you can't distinguish it from the original. And yet the original designer or owner of the intellectual property rights does not get a penny from the sale.

 

[s2udio]

I Think the original disscusion was about about the validity of the EBay trader.........
If they prove to be fake......and by the traders reputation I belive they are Not,
Then the trader will refund you ...so no problem.
I am quite aware of the ethics of "Fake Chinese goods"

 

[Michael Tibes]

And they can produce great fakes too.

Never heard of a fake anything being called "Great"

Don't get confused between originality and quality. They're separate things. The fake may be so good that you can't distinguish it from the original. And yet the original designer or owner of the intellectual property rights does not get a penny from the sale.

I asume they should be easy to distiguish, because the 604 types are kinda the only ones which are running on +/- 24 V? I wonder what happens to a TL072 if I run it on those voltages? I'd assume smoke, wouldn't it? It would only make sense to relabel cheap stuff in order to make a profit, so they wouldn't relabel other hi end opamps to 604s.

Michael

 

[MeToo2]

And they can produce great fakes too.

Never heard of a fake anything being called "Great"

Don't get confused between originality and quality. They're separate things. The fake may be so good that you can't distinguish it from the original. And yet the original designer or owner of the intellectual property rights does not get a penny from the sale.

I asume they should be easy to distiguish, because the 604 types are kinda the only ones which are running on +/- 24 V? I wonder what happens to a TL072 if I run it on those voltages? I'd assume smoke, wouldn't it? It would only make sense to relabel cheap stuff in order to make a profit, so they wouldn't relabel other hi end opamps to 604s.

Michael

It's your Euros, so maybe you should buy them and report back on your experiences.

But why do you assume that the power supply voltage is the only test necessary?
Don't you care about offset voltage? Noise? Bandwidth? Slew rate? Input impedance? CMRR?

They could also be genuine parts with poor fabrication quality that failed parametric testing in the assembly plant, but which escaped the crusher......

 

[okgb]

Someone had posted a link before on how bigger companies & distributors detect fakes
stuff like cleaness of the indentations and printing , do a search , but as bias rocks says
is it worth the possible extra trouble shooting time , sounds like a roll of the dice not to mention
all this internet time , good luck

 

[Michael Tibes]

...But why do you assume that the power supply voltage is the only test necessary?
Don't you care about offset voltage? Noise? Bandwidth? Slew rate? Input impedance? CMRR?

They could also be genuine parts with poor fabrication quality that failed parametric testing in the assembly plant, but which escaped the crusher......

I don't assume it was the only test necessary, but probably the easiest. If they burn they're not original, that's way more obvious than measuring thd etc 

Anyway, if I wouldn't care about those parameters I wouldn't have to make these considerations in the first place, I could just drop 072s into the boxes.

Michael

 

[tubologic]

I Think the original disscusion was about about the validity of the EBay trader.........
If they prove to be fake......and by the traders reputation I belive they are Not,
Then the trader will refund you ...so no problem.
I am quite aware of the ethics of "Fake Chinese goods"

And who's going to refund your wasted time in debugging a circuit which doesn't work as expected due to a sub-standard part ? Counterfeit/mis-branded semiconductors is a worldwide plague and no, they don't all come from China. Tracability is practically impossible and most dealers are honest but don't have the ability to test what they are selling. Just look at the OPA2604 datasheet: do your seller (or you) have the right equipment,knowledge and time to fully test all these parameters to ascertain your OPA2604 is a genuine part ? If it doesn't self-destruct at power up and passes signal doesn't mean your OPA is not a fake.  For a small production run or D.I.Y  I would take no risks and buy only from a reputable dealer. Beware of bargains... a little gain might end up as a big loss.