[fc911c]

Quote:

Originally Posted by fc911c /img/forum/go_quote.gif Hi I have one with no markings at all on the bottom, where any made like this? Thanks Frank

Anyone? I have looked and found 3 more like this that I have.

Thanks
Frank

 

[Henmyr]

Quote:

Originally Posted by oatmeal769 /img/forum/go_quote.gif I've ordered these from them: Matched Pair Burr Brown OPAmp OPA627BP OPA627 OPA637 - eBay (item 140229386618 end time May-31-08 06:16:39 PDT) The picture has the notch and the dimple, and the SN matches the production codes. so We'll see... I'm not sure the ones I got from Tube_Buyer are genuine either.

I also got my OPA627BP from him. I didn't receive the serial number which he had on his auction, but instead a pair of 0018WM155. These (not my picture):

I asked him about the different serial number.

I got this reply:
Quote:

hi, the 43MH51W are sold out. The 0018WM155 are recently acquired and I shall update the website immediately. These lot indeed have better quality when we have placed in the Shanlang CD for testing. Hope you enjoy it. Should you have further query, please do not hesitate to contact us. good day Tri

I'm listening to them right now, and to my ears they sound good, at least thats my first impression, but I have no way of knowing if they are genuine.

Edit:
I find this "These lot indeed have better quality" very strange.

 

[fc911c]

Quote:

Originally Posted by Henmyr /img/forum/go_quote.gif I also got my OPA627BP from him. I didn't receive the serial number which he had on his auction, but instead a pair of 0018WM155. These (not my picture): I asked him about the different serial number. I got this reply: I'm listening to them right now, and to my ears they sound good, at least thats my first impression, but I have no way of knowing if they are genuine. Edit: I find this "These lot indeed have better quality" very strange.

Strange indeed

 

[oatmeal769]

I won't be near my unit again 'till Monday, so I can't check the number, but mine from Tube_Buyer look identical to this - no dimple, but with notch, two color lettering, and numer that doesn't match to T.I. codes. They don't sound 'bad' but I don't hear any significant increase in quality over others I've tried, including the stock one.

 

[Daroid]

Here's the OPA627BP (have two) that i bought in early 2005 i think.
OPA627BP
Click on "Vis det originale billede" to see the full image.
The bottom says PHIL003

and the code is 32ZGK97, which according to TI means:

Manufactured in February 2003, Lot trace code: ZGK9, Assembly site: 7
Both OPA627BPs i have say the same...

 

[dr dougie]

Quote:

Originally Posted by mnemoniak /img/forum/go_quote.gif and I also buy 627's from selectronic, they haven't got the notch on the left, only a dot, they are exactly the same (same serial) as the one's on the link posted by dr dougie (Dual to mono OPAmp OPA2604 LM358 TL072 OPA627 OPA627BP - eBay (item 310018475109 end time May-07-08 23:57:30 PDT)) and they just sounds bad, unlistenable...

Not the ones I bought and I posted that the ones in this link clearly look fake!

Same as Henmyr here with the different ID number than the Ebay guy posted for the ones I got. These do sound good but like Henmyr said there's really no way to tell if they're fake if TI won't get involved.

 

[oatmeal769]

I got the ones I ordered here:
Matched Pair Burr Brown OPAmp OPA627BP OPA627 OPA637 - eBay (item 140229386618 end time May-31-08 06:16:39 PDT)
And as posted above they are NOT the same as advertised, they have a different serial number than the ad. It's 0018WM155
They are exactly identical to the others I have like the picture above, right down to the white lettering.
I am not able to tell an immediate sound difference either.

 

[Golden Monkey]

Man, you guys are depressing me...paranoia is setting in regarding purchasing any op amps online. To this point, which of the posted links for 627's are known legit? Are there other examples of fake chips besides 627's that anyone knows of?

 

[ericj]

Quote:

Originally Posted by dr dougie /img/forum/go_quote.gif Not the ones I bought and I posted that the ones in this link clearly look fake! Same as Henmyr here with the different ID number than the Ebay guy posted for the ones I got. These do sound good but like Henmyr said there's really no way to tell if they're fake if TI won't get involved.

There are plenty of ways to make an educated guess on your own.

For example Ti says that their maximum Iq is 7.5ma per channel - so build a test circuit where you can insert a sensitive ammeter on it's positive voltage rail. If it draws more than 7.5 ma at idle with no load, it is by definition at the very least a defective part.

Even better, build circuits that let you test the input impedance and the voltage offset characteristics.

 

[kipman725]

did TI get the fakes under a scanning tunneling electron microscope at any point? it would be interesting to see what opamps they acualy are!

 

[ericj]

Quote:

Originally Posted by kipman725 /img/forum/go_quote.gif did TI get the fakes under a scanning tunneling electron microscope at any point? it would be interesting to see what opamps they acualy are!

You don't have to do that - you can remove the packaging either mechanically or chemically, and then there are photography methods that let you take a detailed picture of the die itself.

 

[eboy2003]

I heard a tip to quickly identify fake opa627 is to measure the resistance between pin 1 and 5, it should be 45-55k, for both positive, negative direction. Please test it out.

I also bought opa627bp from Matched Pair Burr Brown OPAmp OPA627BP OPA627 OPA637. The one I received is the same as people posted above with white 0018WM155 mark. Tested the resistance between pin 1 and 5, it's only ~18K. These are fakes.

 

[Currawong]

eboy2003: Where did you about the resistance from?

Here's a pic of mine with white lettering. No issues of bad sound here (in fact the opposite) so I can't help wondering if people aren't jumping the gun about fakes.

Edit: Googling images reveals a lot of images of the 627 with white batch numbers starting with "00" and quite a bit of other variation.

Edit 2: These came from Tube_buyer on ebay last year.

 

[Beefy]

Quote:

Originally Posted by Currawong /img/forum/go_quote.gif Edit: Googling images reveals a lot of images of the 627 with white batch numbers starting with "00" and quite a bit of other variation.

They are the same as the ones I got, only that code (from memory) is the same code as seen on my 637AP.

Have a look at the underside of the chips. What do they say?

 

[oatmeal769]

Quote:

Originally Posted by Currawong /img/forum/go_quote.gif Here's a pic of mine with white lettering. No issues of bad sound here (in fact the opposite) so I can't help wondering if people aren't jumping the gun about fakes. Edit: Googling images reveals a lot of images of the 627 with white batch numbers starting with "00" and quite a bit of other variation.

Mine are similar to these. It's not that they sound bad at all... It's that I can't tell any improvement over the stock op-amps. After the reviews here, I'm assuming that for the money I spent, I ought to at least hear a slight difference.