# fake opa627's in the wild.



## adamus

All,

 I recently purchased some opa627's (bp) that didnt work as specified. I contacted Texas Instruments who have since confirmed they are counterfiet. 

 I am waiting from a reply from the supplier before i release details, but its somewhere that has been suggested here as a good cheap source for opa627's. 

 Warning - if they seem too cheap they probably are. 

 Lesson learned on my behalf!


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## d-cee

Yeah it's been happening a while. 

 Was it a proper store or on eBay?

 Would you mind PMing me?


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## tomb

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_All,

 I recently purchased some opa627's (bp) that didnt work as specified. I contacted Texas Instruments who have since confirmed they are counterfiet. 

 I am waiting from a reply from the supplier before i release details, but its somewhere that has been suggested here as a good cheap source for opa627's. 

 Warning - if they seem too cheap they probably are. 

 Lesson learned on my behalf!_

 

Wow - I was wondering what your/their results were. First, I'm glad you figured it out with TI's help. Second, I'm sorry if you lost money on them. Hopefully TI will make you a nice award for some real opamps - you deserve it!


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## Pars

Yes, thanks for taking the time and effort to have these evaluated by TI! Sorry it turned out bad, but good to know if you save anyone else from a similar fate. Hopefully the seller will refund your money as well.


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## slowpogo

I bought some OPA637's cheap on ebay, and they actually sounded very good to me, no doubt about it. I had assumed they were old engineering samples someone rescued from the trash or something.


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## adamus

mine were not from ebay. I got them on a recommendation from this forum. Its more than likely the upplier is oblivious to them being fake. 

 Lets hope i get a refund.


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## joneeboi

What about them did TI say identified them as fakes?


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## adamus

the number didnt tally to any of their production. The housing was unlike anything they make (no notch but with the bb logo).


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## Nisbeth

Do you have any pictures of them? Would be nice to see the silkscreen etc.

 /U.


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## adamus




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## CountChoculaBot

So... does this mean the $11 OPA627BP's from diykits.com.hk are probably fake?


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## ericj

I would venture to guess that since Ti's qty1k wholesale price is currently advertised as $17.75 per each, that the $11 price point is extremely suspect. 

 When people resell engineering samples on ebay, 2 or 5 at a time, that's one thing, and the price can go anywhere. but someone stocking them and offering them at substantially less than wholesale? either stolen or fake.

 ($17.75 is for the opa627bp. the ap version is $12.25, but the pictured parts are BP, and $11 is still unlikely for a small retailer to sell the AP version either.)

 (Further edit - especially considering that opa627 parts are out of stock with a lead time of at least 20 weeks, genuine production overstock lots from factories that bought at qty1k would thus be of accutely high value and would probably be sold at or above market value to other board manufacturers rather than dumped as surplus)


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## CountChoculaBot

Good pics of real OPA627BP's:
OPA627BP Photo: Enlarged


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## dr dougie

OPA627BP are hard to find these days in my experience! If anyone is interested I bought a pair of OPA627BP from this listing on ebay for $37.98 shipped. They're supposedly from an estate sale. I haven't used them yet but they look legit with the dimple, correct ink colors and a correct looking lot code.


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## ericj

Quote:


  Originally Posted by *CountChoculaBot* /img/forum/go_quote.gif 
_Good pics of real OPA627BP's:
OPA627BP Photo: Enlarged_

 

some of those look remarkably like the op's fakes. 

 They are also the only other pictures i've seen of opa627's with a corner dimple with vertical rather than rounded sides. 

 the "batch codes don't match" explanation, if you look around, is one we've seen before - and it's a good enough reason - but at least once it's been applied to a part that was purchased from Farnell, who is a licensed and reputable dealer.


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## user18

Quote:


  Originally Posted by *CountChoculaBot* /img/forum/go_quote.gif 
_Good pics of real OPA627BP's:
OPA627BP Photo: Enlarged_

 

All the lettering is blocked by the watermarks. I wonder if the ebay one's are legit. They were SOIC, i was tempted to buy a pair, but i don't really need them for anything.


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## threepointone

woooowwww--opa627s are STILL out of stock everywhere? is this the same outage from last year or so (haven't been checking up on these lately)?

 thank god I've got a mini-stockpile of 'em =)


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## ericj

Quote:


  Originally Posted by *threepointone* /img/forum/go_quote.gif 
_woooowwww--opa627s are STILL out of stock everywhere? is this the same outage from last year or so (haven't been checking up on these lately)?

 thank god I've got a mini-stockpile of 'em =)_

 

Well, digikey says their stock is 0, newark says their stock is 0, ti says their stock is 0, and hints that farnell uk might have 1 (one) part, but they're probably wrong because farnell, these days, is the UK wing of Newark. lead time for some opa627 parts is listed by Ti as "20+ weeks" and for others as "please call". 

 I interpret this as meaning that the difet production line is either busy with other things and/or down for maintenance. Remember that this is a very old production line with very small by modern standards 4" wafers.


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## dr dougie

Hmm another of the same seller's listings (that I linked above) has photos of fake OPA627BPs. link

 Here's a photo of the ones I got from them.


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## adamus

heres the offical packages from TI

Top Side Marking for Part


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## adamus

and by the way, i have just been given a full refund no questions asked. 

 Again - if its cheaper than it should be, its not a 627!


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## Vaughn

Crap, I just bought a pair of those from DIYkits.
 Interestingly, they tried to sell me LM4562's instead saying "they
 were much better". This makes me wonder if they didn't know the
 627's were fakes.


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## adamus

try them. They may be. Just measure the DC offset - its enough to kill you phones.


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## tomb

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_heres the offical packages from TI

Top Side Marking for Part_

 

Interesting. It looks like one might interpret from that legend that there's no such thing as a Burr-Brown chip without a center notch in the end.


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## ericj

Quote:


  Originally Posted by *CountChoculaBot* /img/forum/go_quote.gif 
_Good pics of real OPA627BP's:
OPA627BP Photo: Enlarged_

 

After looking at those pictures a bit longer, i'm going to say the last two images are fakes. 

 Two reasons. 

 1: dimple next to pin 1 on the 2nd to last picture has vertical sides. i've not seen this on any burr-brown chip bought from a licensed dealer. We do however see it on the OP's fakes. 

 2: The edges and corners on the top of both of the last two pics are sharp, as though they've been shaved or sanded down. plastic packaged chips generally have soft, rounded edges.


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## ericj

Quote:


  Originally Posted by *dr dougie* /img/forum/go_quote.gif 
_Hmm another of the same seller's listings (that I linked above) has photos of fake OPA627BPs. link

 Here's a photo of the ones I got from them._

 

Those markings and case style are very similar to my OPA637BP's, which appear to be genuine.


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## splaz

Wonder maybe if we should build up a gallery of known fakes and real parts for the more expensive op-amps.

 I have a small stash of some of the cheaper TI/BB chips. The packages all vary slightly with them amongst the different types, like slightly different BB logos,some with all white lettering, some all brown, a few with the batch/date codes in white but the other in brown.

 Apparently which factory they come from, age and of course variations within the different op-amp families leads to this ?

 Oh and Farnell AU has a variant of the 627,SMD with very little stock (8)... but it costs $$$s.


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## ericj

Just been looking through my stash of opamps - no notch in the end + dimple with vertical sides is how every single NJM/JRC part i have is packaged. 

 Every BB part i have has a notch in the end. My opa2604's have a dimple with rounded sides as well. 

 Edit: I have a Ti TL082CP that has a package similar to the OP's parts. The dimple on the JRC parts is closer to the end of the chip than the OP's photos or the tl082 - and no notch. So, Ti does have a factory that produces this package style. Which is not to say that they've ever used it to make BB parts. 

 fwiw i have 1 spare opa627au (so-8) that i could part with. Also a 637bp, which is a superior part but only for gains over 5.


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## dr dougie

It's going to be difficult to tell fakes without dissolving the things down to see the IC. BB came out with the OPA627 in early 1991 I think, then TI bought BB in 2000 and they kept making them until 2006(?). So they were made in at least several fab plants over about 15 years and the TI marking guide wouldn't apply for the chips made before 2000 and who knows if all the plants even used the TI marking guidelines afterwards?

 TI would probably say the code on mine is not legit (0018WM155 - I emailed them but have not heard back yet) but there have been a bunch of people that swear their OPA627BPs and APs with similar codes are the real thing obtained from Burr Brown. I don't know anything at all about pre-TI codes.

 Also the OPA627 supposedly needed more sophisticated production methods than other chips (hence their high cost) and would be difficult to copy. There has been speculation for a long time that fake OPA627s could be remarked cheaper chips like OPA134s.

 So ... I just don't know! The only way to be sure is to buy from TI or authorized dealers which is not currently possible as they've been out of stock for awhile. I will agree that the Burr Brown op amps I remember all have the side center notch, but some of their other chips do not have them.

 Oh forgot to add that one giveaway of fakes is angled lettering as compared to the edges. No matter where the legit ones were made they would not have passed QC with angled lettering.


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## ianp

Quote:


  Originally Posted by *Vaughn* /img/forum/go_quote.gif 
_Crap, I just bought a pair of those from DIYkits.
 Interestingly, they tried to sell me LM4562's instead saying "they
 were much better". This makes me wonder if they didn't know the
 627's were fakes._

 

I ordered them 03/25:






 <p>






 BB with no notches, which does not appear on this page  Top Side Marking for Part Number: OPA627BP.

 They sound OK too, but I have no way of knowing if they are true blue or not.


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## CountChoculaBot

The lettering looks crooked and jumbled on the bottom one. From the guy who said a real manuf would never make one with text that's angled, is this a clear sign? Not to mention the top design not matching any single one on TI's page...

 Also, the position of the labels are different on both. The bottom one's is more to the right.


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## tosh1000

By coincidence I was looking at a review of KingRex inty, and saw a photo of an opamp with what appeared to be an extremely cheesy BB logo, and I immediately thought 'fake'! Anyone know? Scroll down a little more than half way:
kingrex review


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## splaz

Quote:


  Originally Posted by *tosh1000* /img/forum/go_quote.gif 
_By coincidence I was looking at a review of KingRex inty, and saw a photo of an opamp with what appeared to be an extremely cheesy BB logo, and I immediately thought 'fake'! Anyone know? Scroll down a little more than half way:
kingrex review_

 

You mean the one with just two plain Bs in a box ?

 I have some OPA2132s that look similar to that... no idea if they're fine or fake, haven't tried them yet.


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## oatmeal769

I bought these: 
2x Dual to Mono Opamp PCB > OPA627 

 from tube_buyer, along with two of his OPA627BP's. As posted before, I saw a difference, but not alot. I'm still wondering if they might have been counterfeit. 2 opamps, and the adaptor cost me only $28. Hmm....
 The OpAmps looked exactly like this:
2PCS Burr Brown OPamp OPA627 NEW

 (even though these are AP, they still look exactly like the BP) They don't have the dimple, writing looks suspect, Date codes dont match up, etc. Anyhow, my curiosity has bested me, so I bought these:
Matched Pair Burr Brown OPAmp OPA627BP 

 today, to see if I can hear a difference. Any thoughts on either of these sellers or choices?


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## Beefy

I bought a pair of 627BP and a pair of 637AP from Parts and Audio.

 They sound pretty much exactly like they should compared to AD8610 in my M^3, but I do suspect they may be fakes. The case style matches those seen on the TI site, but the 10 digit code does not.... the size/positioning of the code is also different between the 627 and 637.

 Finally, the 637 seems very stable at a gain of 2. Realistically, it should oscillate or ping like crazy.


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## Beefy

Just an update to my post above. When I got home from work, I had a closer look at my OPA6x7 from Parts and Audio and I believe more than ever that they are fake. Within each pair the OPAMPs have the same top markings, but the bottom markings are different. The 637's have 'Korea 11' and 'Taiwan A12'. The 627's have 'Phils A01' (Phillipines?) and 'Tawain A07'.

 You would have thought that with the same top markings, they would come from the same location.......


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## oatmeal769

BUDDY CHRIST!!!
  Quote:


  Originally Posted by *Beefy* /img/forum/go_quote.gif 
_The case style matches those seen on the TI site, but the 10 digit code does not...._

 

The date code on mine makes no sense either, and there is no 'dimple'. I'm hoping the new ones I got will show a difference. If they do, I'll be sure to post pix of the ones I have now and where I got them, as fakes.
 The ones I just bought on eBay had the date code in the listing, and it checks out. In the pictures, they look authentic too.


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## splaz

I think a problem may now be though if there ever was slightly different markings used or they had different codes when BB was seperate from TI or some such, some people might think a possibly genuine part is fake.

 Also a problem with listening tests could be if it looks fake, it might be possible sub consciously you start to think what your hearing is definitely fake when it might not be.

 Then again a fake might be a pretty decent op-amp that's been rebranded that most people wouldn't pick up on.


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## oatmeal769

Quote:


  Originally Posted by *splaz* /img/forum/go_quote.gif 
_I think a problem may now be though if there ever was slightly different markings used or they had different codes when BB was seperate from TI or some such, some people might think a possibly genuine part is fake.

 Also a problem with listening tests could be if it looks fake, it might be possible sub consciously you start to think what your hearing is definitely fake when it might not be.

 Then again a fake might be a pretty decent op-amp that's been rebranded that most people wouldn't pick up on. 
	

	
	
		
		

		
		
	


	


_

 

All good points. The differences between different opamps is so small anyway, the psychoacoustic effect could really play havoc.
 Still though, with all the posts from people who have the real deal, I'm hoping a difference will be readily apparent.


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## Harryo

Quote:


  Originally Posted by *dr dougie* /img/forum/go_quote.gif 
_Hmm another of the same seller's listings (that I linked above) has photos of fake OPA627BPs. link

 Here's a photo of the ones I got from them._

 

A fellow eBayer has pointed me in the direction of this thread.

 I have bought a couple of OPA627BPs from the same eBay seller as 'dr dougie' and the opamps have the same number as shown in the photo (0018WM155), are these in fact fakes?

 Harryo


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## Henmyr

Quote:


  Originally Posted by *Harryo* /img/forum/go_quote.gif 
_A fellow eBayer has pointed me in the direction of this thread.

 I have bought a couple of OPA627BPs from the same eBay seller as 'dr dougie' and the opamps have the same number as shown in the photo (0018WM155), are these in fact fakes?

 Harryo_

 

I want to know this too. I also have a pair of 0018WM155 sitting here.


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## mnemoniak

Well, my two cents in here, I bought 627's from tube_buyer (ebay), those with the notch, they work perfectly, 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...


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## fc911c

Hi

 I have one with no markings at all on the bottom, where any made like this?

 Thanks

 Frank


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## oatmeal769

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.


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## adfinni

Got mine off an american seller a few years ago off ebay and all was good then.

 Ive actually got 8 of the SMT variety spare, as well as x2 on some BD adapters with some AD8610 op-amps that I used in my marantz cd-63. If I find them Il put up a FS thread here.


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## 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


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## 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.


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## 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


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## 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.


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## 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...


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## 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.


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## 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.


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## 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?


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## 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.


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## 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!


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## 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.


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## 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.


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## 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.


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## 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 6*3*7AP.

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


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## 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.


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## Beefy

Quote:


  Originally Posted by *oatmeal769* /img/forum/go_quote.gif 
_After the reviews here, I'm assuming that for the money I spent, I ought to at least hear a slight difference._

 

Well, that's a different matter altogether.......

 It very much depends on the amp. Something like a Cmoy will see a big difference between OPAMPs because the power supply is crude and the chip drives the headphones directly. Relative strengths and weaknesses will show through strongly.

 But in something like an M^3 or PPAv2, where the OPAMPs have a very stable power supply, are biased very deeply into Class A, and are only driving discrete output stages..... it all makes the OPAMPs much less of a factor in the final sound.


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## Currawong

Quote:


  Originally Posted by *oatmeal769* /img/forum/go_quote.gif 
_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._

 

I only have my Apogee Duet to compare to, where my ZERO has the 627's installed. I'd say the Apogee wins on clarity, but only just, as it's otherwise much more analytical and the ZERO/627 combo is much warmer. However, for all I know it could be the difference in connection. Considering that the people who have bought obvious fakes have had terrible sound, I think we'd be beating it up seriously saying that anything that didn't perfectly match the marking guide on TI was a fake.


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## AudioCats

I start to wonder if my ebay SOIC 627's are fake...


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## eboy2003

Quote:


  Originally Posted by *Currawong* /img/forum/go_quote.gif 
_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._

 

Just take out your opa627 from the socket and measure the resistance between pin 1 and pin 5 using a multimeter. Try red on pin 1 and black on pin 5, then black on pin 1 and red on pin 5, both measure should read 45-55K. 

 I tested with my real opa627au, the read is about 52K.

 I got the info here, if you can read chinese. China is the place most of the fake come from, the hifier there have the most experience to identify fakes.


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## fc911c

I measured all of mine, I am only seeing about 7.5K on pins 1 and 5

 Frank

  Quote:


  Originally Posted by *eboy2003* /img/forum/go_quote.gif 
_Just take out your opa627 from the socket and measure the resistance between pin 1 and pin 5 using a multimeter. Try red on pin 1 and black on pin 5, then black on pin 1 and red on pin 5, both measure should read 45-55K. 

 I tested with my real opa627au, the read is about 52K.

 I got the info here, if you can read chinese. China is the place most of the fake come from, the hifier there have the most experience to identify fakes._


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## rds

hmmm... I'll measure mine. They're from digikey so I'm pretty sure they're the real thing.
 Just a minute...

 EDIT: I have 3 OPA627AP: 57k, 58k, and 65k


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## Currawong

My dodgy old Tandy multimeter wouldn't go over 20k, even with a slightly flat battery on the pins. Ouch. Might have to get some 627's from a known good source and see what the difference is.


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## Henmyr

Quote:


  Originally Posted by *oatmeal769* /img/forum/go_quote.gif 
_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._

 

I definitely hear a difference between those OPA627bp and the stock OPA2604. On OPA2604, the vocals are slightly laid back and more dry than OPA627BP(fake not fake?. Thats my impression of them.

 Test of OPA627:

 OPA627BP 0018WM155
 20,7K Bottom says: Taiwan M12
 19,9K Bottom says: Taiwan J06

 OPA627AP 9912WM1035
 N/A Bottom says: Japan F e 4
 N/A Bottom says: Japan J III

 It was very strange though. I hope the picture below explain my oddity. Which pin is 1 and which is 5?




 From this, both the AP I got from Dyikits and the BP I got from Matched Pair Burr Brown OPAmp OPA627BP OPA627 OPA637 - eBay (item 140229386618 end time May-31-08 06:16:39 PDT) is fake.


----------



## naamanf

Just looked at the 627APs I had sitting around. From the looks and the readings between pin 1-5 I would say they are fakes. Boo.


----------



## Henmyr

Quote:


  Originally Posted by *naamanf* /img/forum/go_quote.gif 
_Just looked at the 627APs I had sitting around. From the looks and the readings between pin 1-5 I would say they are fakes. Boo._

 

Which pin 1 and which is pin 5, and what is your serial number on them and what reading did you get?

 EDIT: This is all really strange as I find my 0018WM155 to actually sound very good. I A-B between those 0018WM155 and LT1028 just now, and with this short A-B I prefer the 0018WM155. If these are not OPA627BP then what are they?


----------



## rds

In your image pin 1 and 5 are labeled n/a on the AP and 19.9 on the BP


----------



## Henmyr

Quote:


  Originally Posted by *rds* /img/forum/go_quote.gif 
_In your image pin 1 and 5 are labeled n/a on the AP and 19.9 on the BP_

 

So this must mean that the OPA627AP I got from DYIKITS surely is fake since I didn't even get a reading with them?


----------



## Beefy

I just measured my OPA627BP and 637AP that were bought from eBay seller Parts and Audio. All four measured 48-56k ohm between pins 1 and 5.

 I'd like to see more info from people with older models bought from almost-certainly-good sources like Digikey, Farnell etc. I still suspect mine might be fake based on similar date codes, but dissimilar stamps on the bottom of the chip.

  Quote:


  Originally Posted by *Henmyr* /img/forum/go_quote.gif 
_So this must mean that the OPA627AP I got from DYIKITS surely is fake since I didn't even get a reading with them?_

 

Yes, if you can't see any resistance between 1 and 5, they are almost certainly fake.

 This PDF http://focus.ti.com/lit/ds/symlink/opa627.pdf shows that they are connected by 4 resistors in series that are capable of controlling DC offset. In fact, I would measure DC offset with these installed - you'll probably find it is very high. That is what clued in the original poster to these fakes.


----------



## Beefy

Oh, and I just thought I should point out that Digikey currently claims to have stock of the 8-DIP 627AP, 627BP and 637AP.

 I would order some, but international postage costs and shipping time seems a bit nutty just to check.......


----------



## ziplock

This out of stock business almost sounds like TI knows there are a lot of fakes floating around, so they are stopping production to sort out the mess. This is pure speculation of course.

 Anyway, I traded a fellow head-fi member for some 627APs early last year. Pins 1 and 5 read ~52k ohms. Probably from samples before they stopped giving them away.

 They have the notch on the left side and the production code is in white lettering.

 I think if you want to get rid of any doubts, purchase directly from TI when they are back in stock.


----------



## eboy2003

Quote:


  Originally Posted by *Beefy* /img/forum/go_quote.gif 
_I just measured my OPA627BP and 637AP that were bought from eBay seller Parts and Audio. All four measured 48-56k ohm between pins 1 and 5._

 

You might be just lucky to get a OPA627AP remarked to BP. Also remember to measure resistance in both positive/negative directions, I see some fakes measures different resistance from different directions. For me, the 4 0018WM155 opa627bp got from ebay seller trigeminal05, one has no read, the other three has around 18K. I guess the ones have 18K resistance are remarked AD711, and the one without resistance could be anything from junk JRC to opa132/134.


----------



## Harryo

I also purchased two OPA627BP from the same eBay seller.

 One opamp gives a reading of 21.6K and the other 22.9K between pins 1 and 5.

 Harryo


----------



## naamanf

Mine didn't read anything. 

 I have some legit 637s that read about 50k.


----------



## Beefy

Quote:


  Originally Posted by *eboy2003* /img/forum/go_quote.gif 
_Also remember to measure resistance in both positive/negative directions, I see some fakes measures different resistance from different directions._

 

Yes, same resistance in both directions, as per the schematic.

  Quote:


  Originally Posted by *naamanf* /img/forum/go_quote.gif 
_I have some legit 637s that read about 50k._

 

Interesting. More confirmation anyone?


----------



## coredump

I bought the OPA627AP from Digikey and the OPA627BP off ebay.

 The BPs read at 52k and 54k
 The APs read at 64k and 60k

 One very noticeable difference between the two is the volume level. If I have the knob at 9:00 for the AP, I need to turn it to 11:00 for BP to reach the same volume.

 In my opinion the APs sound better. They have more separation and clarity. The BPs sound slightly veiled by comparison. I realise these two aren't the same model so perhaps the comparison is flawed.


----------



## Penchum

Ok, I gave into pressure, and got out my trusty meter. Here are the results with info:

 OPA627BP's bought from Tube_Buyer on eBay. #0045WM3805. Notch and no circle dimple thingy. Lettering in two colors like the other photos. Circle on bottom with TAIWAN and L01 in center. Pin 1+5 check, both directions = 53K

 OPA627AU's from Lawrence. I can only read the model number, they are so small. One on top and one underneath the adapter. Pin 1+5 check, both directions = 52K

 So, I have two "good" sources with these. Like I posted in the Zero review thread, I can't tell the difference between the BP's and AU's, now I know why. 
	

	
	
		
		

		
			





 If someone could check Tube_Buyers other numbered BP's, then we would know if his current batch is good. EDIT: Coredump (over in the Zero thread) pin checked his BP's from Tube_Buyer, they are the same as mine, but the number is 0036WM8420, and he got in the 50's for a reading as well. 
	

	
	
		
		

		
		
	


	



 Lawrence has more AU's already on an adapter ready to go.


----------



## AudioCats

One on the left was from Digi-Key, so assumeablely legit, the one on the right was from eBay. pin1/5 reading: Digi-key= 51k, eBay=53k, pretty close....


----------



## Penchum

Looks like your good to go.


----------



## Currawong

Quote:


  Originally Posted by *Henmyr* /img/forum/go_quote.gif 
_Which pin 1 and which is pin 5, and what is your serial number on them and what reading did you get?

 EDIT: This is all really strange as I find my 0018WM155 to actually sound very good. I A-B between those 0018WM155 and LT1028 just now, and with this short A-B I prefer the 0018WM155. If these are not OPA627BP then what are they?_

 

x2.


----------



## AudioCats

pin 1 is the one at the dot, pin 5 is the one diagonal from it.


----------



## AudioCats

my ebay ones were from here, for some reason the seller doesn't use closed-up pictures. That was why I was skeptical about the authenticity of it. And the price was so very low....


----------



## AudioCats

now, are we sure the pin1/5 resistance measurement is a reliable way to check these chips? 
 Is it possible that other BB chips might have similar resistor network built in?


----------



## Penchum

Quote:


  Originally Posted by *AudioCats* /img/forum/go_quote.gif 
_now, are we sure the pin1/5 resistance measurement is a reliable way to check these chips? 
 Is it possible that other BB chips might have similar resistor network built in?_

 

Well, it is looking like it is the only reasonable method at the moment. Your seller claims his are verified, and you get good readings from them, so that is a good sign I would think. I've felt that my BP's from Tube_Buyer were good all along, but once measured, I feel far more certain now.

 Many folks are coming up with wrong readings, from chips bought from certain sellers, that do not sound good, so this also adds a small amount of validity to the measurement idea.

 The more confirmation we get, that the good sounding ones read correctly, the better this will get. 
	

	
	
		
		

		
		
	


	




 The notch vs circle, printing, shape and bottom, all seem to vary too much for a "overall" rule. Or I have missed something.


----------



## eboy2003

Another tip, if you buy opa627 metal can, AM, BM, SM, make sure pin 4 is connected to the can. Combine with pin 1, 5 resistance check, it pretty much guarantees to detect the fake.


----------



## Hardflip

I got these on May 4 from tube_buyer on Ebay. They measure 52.6K. Their sound is right on, but like Penchum I am happy to have some sort of verification.


----------



## Beefy

Quote:


  Originally Posted by *Hardflip* /img/forum/go_quote.gif 
_I got these on May 4 from tube_buyer on Ebay. They measure 52.6K. Their sound is right on, but like Penchum I am happy to have some sort of verification._

 

It seems like tube_buyer / Parts and Audio is the only eBay source that isn't selling _obvious_ fakes.

 But with Digikey having stock, there isn't much reason why US-based folk at least wouldn't get them there.


----------



## ianp

I reference Henmyr's handy diagram when discussing measurements:







*First set from DIYKITS :*

 Measurement as per the AP chip in Henmyr diagram, that is to say across pins above and below the dot on same side of IC :-

 chip 1 = 22.1
 chip 2 = 24.5 






*Second set from eBay seller TUBE_BUYER*

 Measurement as per the BP chip in Henmyr's diagram, that is to say pins at opposite sides and ends of IC :-

 chip 1 = 47.6
 chip 2 = 51.6

 My ICs are exactly the same as Hardflip's - Same serial, etc - as shown below:


----------



## Penchum

Quote:


  Originally Posted by *Hardflip* /img/forum/go_quote.gif 
_I got these on May 4 from tube_buyer on Ebay. They measure 52.6K. Their sound is right on, but like Penchum I am happy to have some sort of verification._

 

Excellent! That is three of the same numbered sets now, that have the 0036WM8420 number, and they check good!


----------



## MrMajestic2

Quote:


  Originally Posted by *Beefy* /img/forum/go_quote.gif 
_It seems like tube_buyer / Parts and Audio is the only eBay source that isn't selling obvious fakes.

 But with Digikey having stock, there isn't much reason why US-based folk at least wouldn't get them there._

 

Or in europe for that matter. Digikey shipping for a few chips isnt too bad I think. Maybe a groupbuy is in order


----------



## oatmeal769

Quote:


  Originally Posted by *Penchum* /img/forum/go_quote.gif 
_Excellent! That is three of the same numbered sets now, that have the 0036WM8420 number, and they check good! 
	

	
	
		
		

		
		
	


	


_

 

Cool, I have this set as well (0036WM8420). Thanks for the verification! Guess I'll just have to train my ears more. To me the differences are at best subjective from the stock ones.


----------



## Currawong

An update: My "white-text" 627's were bought by the previous ZERO owner from tube_buyer. I'm not going to trust my 20yo Tandy meter with semi-flat battery to give a good reading.


----------



## Henmyr

Quote:


  Originally Posted by *Currawong* /img/forum/go_quote.gif 
_An update: My "white-text" 627's were bought by the previous ZERO owner from tube_buyer. I'm not going to trust my 20yo Tandy meter with semi-flat battery to give a good reading._

 

Are you talking about 0018WM155? We are three people I think who have measured them, and all of us ended up with around 20K, so it's not your tandy meter.

 So you're saying tube_buyer has sold 0018WM155?

 This is all very strange, as I prefer my supposedly fake OPA627BP to my other opamps based on the sound I get from them. I find it very hard to believe that they are just some crap op-amp, and if they are, I would like to buy more of them for the real price, which might be only a few dollars.


----------



## Currawong

Yup, talking about the 0018WM155 chips and yes, the previous owner of my ZERO I asked and he said he bought his 627's from tube_buyer on eBay.

 I'm not going to trust the info about the resistance reading, simply because we don't know enough about where it came from, and, most importantly, WHY they should read at 55k or so, especially considering it's a reading between pins that, at least in my DAC, aren't used. The only way we'll know for sure is if TI says one way or the other about the chips and batch numbers on them.

 Anyone know who to contact at TI?


----------



## Penchum

Quote:


  Originally Posted by *Currawong* /img/forum/go_quote.gif 
_An update: My "white-text" 627's were bought by the previous ZERO owner from tube_buyer. I'm not going to trust my 20yo Tandy meter with semi-flat battery to give a good reading._

 

 Quote:


  Originally Posted by *Currawong* /img/forum/go_quote.gif 
_Yup, talking about the 0018WM155 chips and yes, the previous owner of my ZERO I asked and he said he bought his 627's from tube_buyer on eBay.

 I'm not going to trust the info about the resistance reading, simply because we don't know enough about where it came from, and, most importantly, WHY they should read at 55k or so, especially considering it's a reading between pins that, at least in my DAC, aren't used. The only way we'll know for sure is if TI says one way or the other about the chips and batch numbers on them.

 Anyone know who to contact at TI?_

 

I think you should get a new battery for your meter. 
	

	
	
		
		

		
		
	


	




 The source link for the measurement idea was in this post: http://www.head-fi.org/forums/f6/fak...ml#post4243931 In this post: http://www.head-fi.org/forums/f6/fak...ml#post4244973 is the link which tells what is being measured on the OPA627 and why it should read the higher numbers. I'm just pointing these out. I'm no chip expert, so I have to rely on others too. 
	

	
	
		
		

		
		
	


	




 The Goggle translation of the Chinese site, just made me laugh.


----------



## oatmeal769

I just read somewhere that when TI shut down the original BB plant after acquisition, TI outsourced the manufacture of the 627 series to Asia to save money. Several Asian manufacturers made the 'genuine' 627 under TI's licence, but most did not meet the original specs of the USA BB made ones. 

 If this is true, then anyone selling these Asian remakes is not lying if they say they are 'genuine', even if the remake isn't quite up to true specs. It may be also that these are 'better' than the usual op-amp in it's league, but still not quite the genuine article.

 I wonder if there are other tests to verify integrity?


----------



## coredump

Well that would complicate things a bit.


 While I would think my OPA627AP and OPA627BP chips should sound the same they in fact sound different.


----------



## Henmyr

I just got an email from tube_buyer:

  Quote:


 By the way, for your concern of fake OPA627, we usually will check the power consumption of the opamp, that is... it will consume around 7ma current. When we buy it from our vendor we will do this procedure to make sure it is OPA627. 
 

How do I measure the power consumtion?


----------



## Beefy

Quote:


  Originally Posted by *coredump* /img/forum/go_quote.gif 
_While I would think my OPA627AP and OPA627BP chips should sound the same they in fact sound different._

 

Hmmmmm, they _should_ sound the same. The difference between grades is usually in DC performance, not AC.

 One or both of your chips is probably fake.


----------



## ericj

Quote:


  Originally Posted by *Henmyr* /img/forum/go_quote.gif 
_I just got an email from tube_buyer:



 How do I measure the power consumtion?_

 

with an ammeter


----------



## jim.carr

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_



_

 

Thanks for sharing the info 
	

	
	
		
		

		
		
	


	




. Counterfeit are everywhere now days... 
	

	
	
		
		

		
		
	


	




 I was considering to get some from Ebay... but now I think I will just hold it off or get it from RS (a little expensive but. at lease it will be the real thing).


----------



## Penchum

Quote:


  Originally Posted by *coredump* /img/forum/go_quote.gif 
_Well that would complicate things a bit.


 While I would think my OPA627AP and OPA627BP chips should sound the same they in fact sound different._

 

When I bought my first BP's from Lawrence late last year, I had read many posts about the BP sounding "better" than the AP. I really believe this is more likely to be "different" than "better", but some folks are really into those extremely small changes. 
	

	
	
		
		

		
			





 If you have a big difference between the two types, then I would be suspicious about it. My understanding is that the "difference" is very small, to a point where some folks will not detect it.


----------



## threepointone

The absolute definite way to test for "fakes" is to test all the parameters specified in the OPA627 data sheets. The majority of the cost of your IC actually goes to testing each one of the chips, and a real OPA627 will have specs which should fall within what's given. I'd imagine if they were _really_ good counterfeits, it's not really difficult to fake what you're testing right now (resistance and current draw). 

 Obviously, you can't test them all, but I'd go for something that actually costs them to "counterfeit"--offset voltage and bias current. Of course, it's a bit more difficult, but you can probably find the testing schematic in the datasheet, and it's probably the safest way to tell.

 Another thing to note: I just noticed that the rough schematic of the opa627 is on the datasheet. It's possible that another counterfeiting company has simply managed to duplicate the IC, or just decapped it and did a bit of reverse engineering. Again, the majority of the cost of the opa627 is probably due to the laser trimming of components and throwing out all the ICs that are way out of spec--I'm going to try avoiding any arguments about psychoacoustics and whether or not there actually are audible differences among opamps, but chances are the majority of the cost of the opa627 goes to things completely unimportant for audio circuits (the offsets, as I mentioned before). But of course they'd still be charging you the same amount of money and screwing you over for what you paid. So again, probably the safest way to test for counterfeits is to measure the offsets--if the counterfeit actually is good enough to do as well as the datasheet, the counterfeit may as well be as good as the real thing.

 [EDIT]
 that reminds me: the almighty bob pease has a short series of articles about how he set the testing equipment to measure the bias current on a truly uber-low bias current op-amp. I don't think you'll have to be quite as careful for the opa627, but I'd imagine the measurement techniques are the same: What's All This Femtoampere Stuff, Anyhow?


----------



## Frwkie

Hello, I bought some OPA627BPs from tube_buyer. The strange thing about them is that you have to place them with the text in the other direction than normally. They don't sound bad at all, and the resistance between pin 1 and 5 is measured as ~51k. Below you'll find a picture of them. Didn't found any similar looking opas on the internet, though. Any thoughts on authenticity?


----------



## coredump

Mine are the same way. If I put them with the top of the text against the wall I get noise. If I flip them around with the bottom of the text against the wall they work fine.


----------



## Frwkie

Ok, so we've the same, and are placing them the same way! The resistance is in the proper range, I found out. What's your feeling on how they sound? At this time no complaints in my case, but I'm relatively new in the hifi world


----------



## coredump

Well I didn't like them as much as my OPA627APs.


----------



## Penchum

Quote:


  Originally Posted by *Frwkie* /img/forum/go_quote.gif 
_Ok, so we've the same, and are placing them the same way! The resistance is in the proper range, I found out. What's your feeling on how they sound? At this time no complaints in my case, but I'm relatively new in the hifi world 
	

	
	
		
		

		
		
	


	


_

 

Well, if they sound good, test good, then you are at the same spot as the rest of us, who believe ours are good. 
	

	
	
		
		

		
		
	


	




 Tube_Buyer has been good to many of us, so I continue to hope all is well.


----------



## Harryo

I have just purchased "1 MODULE OF 2 Pre-Mounted OPA627AU Op-amps on Adapter" from a seller on eBay.

 In his description of the item the seller even quoted a measurement figure for Pins 1 and 5 of 52K ohms (I measured it at 52.8K ohms 

 Maybe this is a new trend on eBay or they are responding to this thread!

 Harryo


----------



## Penchum

Quote:


  Originally Posted by *Harryo* /img/forum/go_quote.gif 
_I have just purchased "1 MODULE OF 2 Pre-Mounted OPA627AU Op-amps on Adapter" from a seller on eBay.

 In his description of the item the seller even quoted a measurement figure for Pins 1 and 5 of 52K ohms (I measured it at 52.8K ohms 

 Maybe this is a new trend on eBay or they are responding to this thread!

 Harryo_

 

I believe they pay attention to us. 
	

	
	
		
		

		
		
	


	




 The ones that care, don't want to sell fake opamps and then have to eat the cost after refunding. It looks like some of them are on "our" side.


----------



## JamesL

Has anybody bought from goodbuy711 on ebay?

opa627bp
 He's selling 10 pieces for just under $9 each, compared to $27 a pop from digikey.
 I need 3 for a ppav2 I'm doing, so if these were legitimate, and I could find some way to sell the other 7 chips (maybe two pairs, and a set of 3), I'd be good to go.


----------



## adamus

fake - check the housing list from TI


----------



## Beefy

Quote:


  Originally Posted by *JamesL* /img/forum/go_quote.gif 
_Has anybody bought from goodbuy711 on ebay?

opa627bp
 He's selling 10 pieces for just under $9 each, compared to $27 a pop from digikey._

 

Just get the *A*P for less money from Digikey. You won't hear any difference.


----------



## oatmeal769

They don't have 'the notch,' they very well could be fake, especially for $9.


----------



## Harryo

Quote:


  Originally Posted by *JamesL* /img/forum/go_quote.gif 
_Has anybody bought from goodbuy711 on ebay?

opa627bp
 He's selling 10 pieces for just under $9 each, compared to $27 a pop from digikey.
 I need 3 for a ppav2 I'm doing, so if these were legitimate, and I could find some way to sell the other 7 chips (maybe two pairs, and a set of 3), I'd be good to go._

 

I thought I'd have a dabble and purchased a pair, the measurement across pins 1 and 5 is 6.2K ohms, the code on the chips is 63DK5VT.

 Reading through the guys feedback I see someone has just purchased ten of the chips!

 In a message in response to an email I sent him the seller said he would be contacting his supplier re the 'low' reading on pins 1 and 5 of the chips that I purchased.

 Adamus in his post mentions "the housing list from TI" is there a URL link to this list, I would like to check the code 63DK5VT before sending an email to the fellow eBayer who has purchased ten of the chips.

 Harryo


----------



## adamus

its in this thread somewhere i think. sorry i cant dig it out, got to dash to work.


----------



## JamesL

Quote:


  Originally Posted by *Beefy* /img/forum/go_quote.gif 
_Just get the *A*P for less money from Digikey. You won't hear any difference._

 

The opa627AP's are $18 each at digikey.. am I missing something?
 Anyways, I think I'm going to opt for the surface mount opa627AU's from mahil69, and use them with adapters. He was kind enough to offer sets of 3.
 The AU's offer the same or similar quality to that of the AP, right?


----------



## FallenAngel

Quote:


  Originally Posted by *JamesL* /img/forum/go_quote.gif 
_The opa627AP's are $18 each at digikey.. am I missing something?
 Anyways, I think I'm going to opt for the surface mount opa627AU's from mahil69, and use them with adapters. He was kind enough to offer sets of 3.
 The AU's offer the same or similar quality to that of the AP, right?_

 

yes, of course, they are the same chip.


----------



## oatmeal769

Quote:


  Originally Posted by *Henmyr* /img/forum/go_quote.gif 
_




_

 

I can indeed confirm that serial number 0018WM155 627BP from 'House of Lord /trigeminal05' Matched Pair Burr Brown OPAmp OPA627BP - eBay item 140229386618
 are in fact FAKE! I just measured 21.5 Kohms across pin 1 and 5.

 I'm going to sample my other set from another seller now... I'll post back when I get them out of my Zero.


----------



## AudioPhewl

I just measured my three OPA627APs, and they're reading from 60.5k to 64.5kohms. Is this bad?

 ~Phewl.


----------



## oatmeal769

I just measured another set I have from Tube Buyer on eBay: 

eBay My World - tube_buyer

 They measure at 50.3 and 61.1 respectively. The 50.3 is right on, I'm wondering if the 60.1 is too high...?


----------



## AudioPhewl

Just read the whole thread through - I'm happy that they're genuine(I was before, but found it all interesting). I had them through the BB/TI sample program, but snapped one of the legs(an expensive mistake!!).

 From reading through this thread, it seems BP variants tend to read 55-60k, and AP variants 60-65k.

 I'd say it's a safe-bet that 60-65k is on the money, seeing as TI shipped them direct to me... 
	

	
	
		
		

		
		
	


	




 For the record, a genuine OPA227 reads infinity between pins 1 and 5. An LT1028 reads 7.5M ohms between pins 1 and 5.

 ~Phewl.


----------



## Henmyr

Quote:


  Originally Posted by *oatmeal769* /img/forum/go_quote.gif 
_I can indeed confirm that serial number 0018WM155 627BP from 'House of Lord /trigeminal05' Matched Pair Burr Brown OPAmp OPA627BP - eBay item 140229386618
 are in fact FAKE! I just measured 21.5 Kohms across pin 1 and 5.

 I'm going to sample my other set from another seller now... I'll post back when I get them out of my Zero._

 

I have this measure also, around 21.5Kohms. The reason I'm hesitant to call them fake is the sound. The sound like no other op-amp I have, AND they sound good. The have the largest soundstage of all my op-amps, something that the OPA627 is reported to have.

 EDIT: How do they compare in sound to your amps from Tube_Buyer?


----------



## Currawong

Quote:


  Originally Posted by *oatmeal769* /img/forum/go_quote.gif 
_I can indeed confirm that serial number 0018WM155 627BP from 'House of Lord /trigeminal05' Matched Pair Burr Brown OPAmp OPA627BP - eBay item 140229386618
 are in fact FAKE! I just measured 21.5 Kohms across pin 1 and 5.

 I'm going to sample my other set from another seller now... I'll post back when I get them out of my Zero._

 

I don't believe mine are fake. I have the same ones and they both sound fantastic and came from Tube Buyer (according to the previous owner of my ZERO). We still don't have any absolute confirmation that the measurement is a valid one for testing for fakes except a post in a Chinese forum that almost none of us can read. The only way we'll know for sure is if someone contacts TI and asks them about the serial numbers.


----------



## Henmyr

Quote:


  Originally Posted by *Currawong* /img/forum/go_quote.gif 
_I don't believe mine are fake. I have the same ones and they both sound fantastic and came from Tube Buyer (according to the previous owner of my ZERO). We still don't have any absolute confirmation that the measurement is a valid one for testing for fakes except a post in a Chinese forum that almost none of us can read. The only way we'll know for sure is if someone contacts TI and asks them about the serial numbers._

 

Just so I get this right, you have the 0018WM155 right?


----------



## rds

Quote:


 ...a genuine OPA227 reads infinity between pins 1 and 5. 
 

my mind is blown


----------



## Currawong

Quote:


  Originally Posted by *Henmyr* /img/forum/go_quote.gif 
_Just so I get this right, you have the 0018WM155 right?_

 

That's right. So if they are fake, they'd have to be amazing good quality fakes and have fooled one of our trusted sources. 

 Phewl: Where did you get your information from?


----------



## Penchum

Quote:


  Originally Posted by *AudioPhewl* /img/forum/go_quote.gif 
_Just read the whole thread through - I'm happy that they're genuine(I was before, but found it all interesting).

 From reading through this thread, it seems BP variants tend to read 55-60k, and AP variants 60-65k.

 I'd say it's a safe-bet that 60-65k is on the money, seeing as TI shipped them direct to me... 
	

	
	
		
		

		
		
	


	




 ~Phewl._

 

I believe this is where we left off.

 So far, the only "looks" genuine (has the cut out half circle notch, not the circle) BP, that will not measure properly, is the 0018WM155 numbered BP.

 While I believe the measuring of pins 1 and 5 is a good first check in the process, I think the 0018WM155 numbered BP may be the exception, based on how it sounds to the folks that own them. How it sounds, has to be the last and final check in this madness.

 Perhaps, one of you guys with a set of the 0018WM155 numbered BP's, and a set of the "measures correctly" BP's, can do a comparison between the two and see if they "sound" alike??? This would really help out many owners, that have a set of the 0018WM155 numbered BP's and so far, believe they have a bad set.


----------



## Currawong

Let me add for emphasis that my 0018WM155 in my ZERO sound so good - unholy good with everything else in the chain - and sound just like I've read in every review, that I'd be very surprised if they are fake. As well, the LT1364's in my ZERO's head-amp are different, but not radically different in sound, again, as they've been described in reviews in comparison to the 627.

 So unless something is going on which I'm not aware of, I think we're making a mountain out of a molehill here with this issue.


----------



## Beefy

Quote:


  Originally Posted by *Currawong* /img/forum/go_quote.gif 
_So unless something is going on which I'm not aware of, I think we're making a mountain out of a molehill here with this issue._

 

I think that some of the fakes are 'good' and sound OK, but some are just _bad_. These ones sound awful, and give terrible DC offset.

 Anything that helps weed out and discourage fakes can only be a good thing.


----------



## Penchum

Quote:


  Originally Posted by *Beefy* /img/forum/go_quote.gif 
_I think that some of the fakes are 'good' and sound OK, but some are just bad. These ones sound awful, and give terrible DC offset.

 Anything that helps weed out and discourage fakes can only be a good thing._

 

The bad ones you are talking about, from earlier in the thread right? They aren't the 0018WM155 numbered ones, correct?? Just trying to clarify.


----------



## Beefy

Quote:


  Originally Posted by *Penchum* /img/forum/go_quote.gif 
_The bad ones you are talking about, from earlier in the thread right?_

 

Yes, that's right


----------



## Penchum

Quote:


  Originally Posted by *Beefy* /img/forum/go_quote.gif 
_Yes, that's right 
	

	
	
		
		

		
		
	


	


_

 

Sorry, you chopped off my second question part. "They aren't the 0018WM155 numbered ones, correct??"


----------



## Beefy

Quote:


  Originally Posted by *Penchum* /img/forum/go_quote.gif 
_Sorry, you chopped off my second question part. "They aren't the 0018WM155 numbered ones, correct??" 
	

	
	
		
		

		
		
	


	


_

 

I don't have any of those numbered OPAMPs, so I really don't know. My judgment on the really bad ones comes from the OP


----------



## Penchum

Quote:


  Originally Posted by *Beefy* /img/forum/go_quote.gif 
_I don't have any of those numbered OPAMPs, so I really don't know. My judgment on the really bad ones comes from the OP 
	

	
	
		
		

		
		
	


	


_

 

Ow, ok, thanks!


----------



## oatmeal769

Quote:


  Originally Posted by *Henmyr* /img/forum/go_quote.gif 
_ How do they compare in sound to your amps from Tube_Buyer?_

 

I have not closely A/B'd them, but I don't recall any noticeable difference. 
 Then again, I can barely tell a difference between the 627BP and stock. My ears must not be 'all that'.


----------



## Pricklely Peete

Mine are marked (from tube buyer) 0036WM8420 on all 4 of them.They are BP's FWIW.

 Peete.


----------



## Penchum

Quote:


  Originally Posted by *Pricklely Peete* /img/forum/go_quote.gif 
_Mine are marked (from tube buyer) 0036WM8420 on all 4 of them.They are BP's FWIW.

 Peete._

 

Yep, and those should not only sound good, they should test good as well. I have a pair also.


----------



## Itsme

Quote:


  Originally Posted by *JamesL* /img/forum/go_quote.gif 
_Has anybody bought from goodbuy711 on ebay?

opa627bp
 He's selling 10 pieces for just under $9 each, compared to $27 a pop from digikey.
 I need 3 for a ppav2 I'm doing, so if these were legitimate, and I could find some way to sell the other 7 chips (maybe two pairs, and a set of 3), I'd be good to go._

 

--------------------------------------------------------------------------

 WARNING: Ebayer seller Goodbuy711 (ALLPARTSPIPE-Ebay store) is knowingly selling counterfeit Burr Brown OPA627BP chips. They have been contacted several times from buyers of the chip including me, telling them that they are selling counterfeit chips. And they respond back that they will contact their supplier. But continue to sell them.
 I have reported to Ebay as of today that they are continuing to sell these chips. In hopes that Ebay will take action.

2pcs, OP AMPLIFIER OPA627BP OPA627 IC IC'S CHIP NEW - eBay (item 270259628265 end time Aug-02-08 17:26:48 PDT)


----------



## Penchum

Quote:


  Originally Posted by *Itsme* /img/forum/go_quote.gif 
_--------------------------------------------------------------------------

 WARNING: Ebayer seller Goodbuy711 (ALLPARTSPIPE-Ebay store) is knowingly selling counterfeit Burr Brown OPA627BP chips. They have been contacted several times from buyers of the chip including me, telling them that they are selling counterfeit chips. And they respond back that they will contact their supplier. But continue to sell them.
 I have reported to Ebay as of today that they are continuing to sell these chips. In hopes that Ebay will take action.

2pcs, OP AMPLIFIER OPA627BP OPA627 IC IC'S CHIP NEW - eBay (item 270259628265 end time Aug-02-08 17:26:48 PDT)_

 

Man, that really sucks! By all means, get them shut down! 
	

	
	
		
		

		
		
	


	




 The safer way to go, is to buy the OPA627AU's mounted on an over/under adapter. They sound the same as the BP's, and so far, everyone who has bought them, has had them test properly, so they are the real thing.


----------



## eboy2003

After carefully measure resistance between all pins and dig thru the datasheets, I think I figured out what these 0018WM155 opa627bp really are. They are *opa602*. opa602 should have constant resistance between pin1 - pin5, pin1 - pin4, pin5 - pin4, but high resistance for pin1 - pin7 and pin5 - pin7. Real opa627 should have constant resistance for pin1 - pin5, pin1 - pin7, pin5 - pin7, but high resistance for pin1 - pin4 and pin5 - pin4. You can test yours.

 Whether the remarked chip was opa602ap or bp is unknown, but heck, if you really like the sound of this fake 627bp, now you know what opamp you can look for cheaper price.


----------



## haloxt

Quote:


  Originally Posted by *Itsme* /img/forum/go_quote.gif 
_--------------------------------------------------------------------------

 WARNING: Ebayer seller Goodbuy711 (ALLPARTSPIPE-Ebay store) is knowingly selling counterfeit Burr Brown OPA627BP chips. They have been contacted several times from buyers of the chip including me, telling them that they are selling counterfeit chips. And they respond back that they will contact their supplier. But continue to sell them.
 I have reported to Ebay as of today that they are continuing to sell these chips. In hopes that Ebay will take action.

2pcs, OP AMPLIFIER OPA627BP OPA627 IC IC'S CHIP NEW - eBay (item 270259628265 end time Aug-02-08 17:26:48 PDT)_

 

A few days ago I bought ten of their opa637bp's 
	

	
	
		
		

		
		
	


	




. Now I'm reading on ebay's policies and seems unlikely to me that he can be made to stop. Is there anything I can do? Send some of his opa637's to the real makers to test its authenticity?


----------



## majkel

Is it possible that there is no circle on the bottom side of the DIP8 package of the OPA627BP? As for this chip sound sucks, I'll report the ebay seller as soon as I'm sure these are fakes. I have lots of Burr Brown op-amps at home, and each one has got a round dent at the bottom. These are flat, and the pins look a bit crappy. All the rest looks OK but sounds less than OK. My original OPA627AU gives nicer sound.


----------



## haloxt

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_Is it possible that there is no circle on the bottom side of the DIP8 package of the OPA627BP? As for this chip sound sucks, I'll report the ebay seller as soon as I'm sure these are fakes. I have lots of Burr Brown op-amps at home, and each one has got a round dent at the bottom. These are flat, and the pins look a bit crappy. All the rest looks OK but sounds less than OK. My original OPA627AU gives nicer sound._

 

Who is the ebay seller? same as mine?


----------



## majkel

No but not yet sure.


----------



## haloxt

LOL well I just put in the fake opa637bp's I got and they sound much worse than lm4562's. Then again there's some things I wonder about. When I set the voltmeter to 200K I get readings of 5.9K on pins 1 and 5, could it be the decimal point is in the wrong spot 
	

	
	
		
		

		
		
	


	




 ?

 If it is actually 59k then I have some other questions, could the crap sound be because my ht omega halo sound card cannot drive 8 of these? Or I need to solder something, because all I did was drop IC sockets on browndog adaptors and the likely fake opamps on the IC sockets and wrapped tape around it all (then dropped it into the IC sockets on my sound card)? I think my sound card can't drive all these opamps because I have to turn volume to max to get the amount of volume as 10% of max volume with lm4562's. Well.. in the meantime I'm going to try taking out the IC sockets and see if there's any improvements with this hilariously crappy sound.


----------



## majkel

First you have to be sure you can use OPA637 as it is unstable in gains below 5 and any integrator-based circuits. The exception is when you use an output buffer and a global feedback loop. 

 I listened to my weird OPA627BP's and I must say they are very good sounding but it's more similar to AD797ANZ sound than OPA627AU which I own. Actually... it's good. 
	

	
	
		
		

		
			





 The resistance readings are credible, too.


----------



## haloxt

opa637 has been used on this card. i'll try putting in the fake opamps in the same location (only two instead of all 4 sockets) as in this post just to see what happens, I really can't believe the fake opamps can sound this bad. what do you guys suggest i do with ebay? seems like they're really screwed up regarding counterfeits.

Guru3D.com Forums - View Single Post - New card: HT Omega Claro HALO!

 edit: well this is my last comment on this topic, I went through the procedure on paypal to report a counterfeit making it clear I didn't want to let the issue go if I got a refund and paypal's answer was for me to mail it back to the ebay seller at my own expense. Apparently ebay/paypal thinks it is kosher to sell counterfeits, so beware of ebay opamps, its scam central.


----------



## joosty

Any idea about this one (see pic), on Ebay for $21 per module. Using the info about marking on Top Side Marking for Part OPA627AU I'm not able to identify them as fakes. Anyone familiar with seller 'gigawork' on Ebay?


----------



## majkel

gigawork is a great seller. He doesn't use any fake parts for his DIY DAC modules.


----------



## sachu

First off, Sorry for shamelessly plugging this.

 I don't know about those but I know that mine were original..I bought them from a friend who worked at TI who got it as a sample...I have had them for the last 2-3 years in my DIY DAC but now I don't need them anymore as I am upgrading to a discrete I/V stage. 

 YOu are welcome to them. check out the link in my signature to go the sale page..


----------



## joosty

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_gigawork is a great seller. He doesn't use any fake parts for his DIY DAC modules._

 

May I ask what makes you say this?

 I just had a second look and according to the third line on the chip it was produced in 2009 (9), in september (9). Looks like a chip from the future 

 Makes me think of counterfeit DVDs and CDs, before the day of the dvdr and cdr. You'd often see very good looking copies that obviously took a lot of effort to produce, but they would often have some spelling errors


----------



## majkel

I've been using a couple of DIY kits from gigawork. This sound couldn't be achieved using fakes. I can't comment the op-amp modules, though. All I can say the OPA627 in any version is overrated. See the review in my signature for details and choose the right op-amp for you.


----------



## majkel

Gotta try the LT1357 pair again and the OPA827 which I didn't know appeared in the meanwhile.


----------



## Nemo de Monet

For what it's worth, you can add the OPA2107 to the list of counterfeited chips on eBay - I've found that one sellers' are fakes, am positive two other sellers are (same lot/date codes, but with different logos, different packages - notch/no notch, smooth/sharp dimples) and suspect from the prices that most of the others are fake, as well. On mine, which were $12.99/pair shipped from Hong Kong, you can literally see where the old markings were sanded off before the new ones were applied.

 I'm fairly certain the chips I received are re-marked OPA2134s, based on listening comparisons versus Mouser-sourced parts in a SOHA and Pimeta... so it's not that they're _bad_, just not what they're advertised as.


----------



## Bilavideo

I'm not buying any more chips off of E-bay, particularly since buying them from either DigiKey or the manufacturer, like AD, is freaking foolproof.


----------



## adamus

indeed, ebay has go so bad it just cant be trusted unless the you know the seller.


----------



## wuwhere

Sorry for resurrecting an old thread. I just bought a pair of OPA627AP from eBay for $10 each. I measured the resistance between pins 1 & 5. Date code 46ZT8L7 = 46.417 kOhms  and date code 46ZT8K7 = 57.81 kOhms. I guess they're legit.


----------



## analog-cabin

I too just bought (16) OPA627BP's off of eBay from aatcc2010. I should have gone with Tube_Buyer.
  BTW, Anyone in the US selling legit op-amps for "fair" prices?


----------



## calico88

Hi there,
  I just got DAC built and now I need Opa 627, 4 pieces, single.
   
  now I'm very confuse which OPA627 is the best and Genuine ??
  I'm looking at Metal cap Opa627SM.... any idea which model is better for Detail SQ ??
   
  and where to get genuine opa beside buying from TI or their distributor like digikeys or mouser  which cost US76 a pop ??
   
  getting from ebay OPA627SM US30,- a pop .... is this real or fake ???
   
  anyone ever compare getting from TI and ebay hongkong ??
  I've been googling and the more I googling the more I confuse.
  and I don't see any clarification on Head-fi either, or at least someone compare OPA627 metal cup !
   
  help ...


----------



## wankski

sorry bud - but its all been said... the only way you can ensure its legit is by buying from a legit reseller.... Digikey or mouser is the go...
   
  been there done that... fortunately eSeller took em back and refunded, but far more trouble than its worth.
   
  That is one of the reasons why i moved away from the m3 to the all-discrete b22.. took opamps out of the equation...


----------



## n00kie

Anybody here bought the OPA627AP with Class A Biasing Mod from tamaudio? http://coolfungadget.com/store/index.php?route=product/product&product_id=91
   
  I mentioned in another hi-fi forum that I purchased the above linked opamps and several users suppose they're chinese fakes. Anybody can apply for this? So if yes how big is the sq loss in comparison to the genuine?


----------



## madwolf

This are the OPA627AP that I got form Element14 formally known as Farnell 
  I bought 2 and soldered it onto an adaptor 
   
  Can anyone tell me if it is real or fake ?


----------



## i_djoel2000

Quote: 





madwolf said:


> This are the OPA627AP that I got form Element14 formally known as Farnell
> I bought 2 and soldered it onto an adaptor
> 
> Can anyone tell me if it is real or fake ?


 

 i think the name of the company itself is already giving a reliable warranty for the product they're selling. i bought tons of stuffs from farnell and i can say none of them are fakes


----------



## Fred_fred2004

I've never had a fake from Farnells, very reliable company


----------



## MrDave

With all the fakes on eBay, is it worth trying to sell any of these op amps there? I'm trying to clean out my basement but I'm kind of sketched out that everyone else posting auctions there are based in China.
   
  Does anyone here still buy these items off eBay?


----------



## Mikesin

Were they fake then from tamaudio?
  
  Quote: 





n00kie said:


> Anybody here bought the OPA627AP with Class A Biasing Mod from tamaudio? http://coolfungadget.com/store/index.php?route=product/product&product_id=91
> 
> I mentioned in another hi-fi forum that I purchased the above linked opamps and several users suppose they're chinese fakes. Anybody can apply for this? So if yes how big is the sq loss in comparison to the genuine?


----------



## jtam

I sold hundreds of the 627AP opamps nobody complained about the genuineness.
  
  Quote: 





mikesin said:


> Were they fake then from tamaudio?


----------



## Mikesin

Thats good  and could you please process with my order then , It's been 6 Days and it been stuck on Pending.. and you haven't replied to emails..
  
  Quote: 





jtam said:


> I sold hundreds of the 627AP opamps nobody complained about the genuineness.


----------



## OPAMPKIM

▲OPA637BP
  ARROW.COM
  D/C 0836
   

  ▲OPA627BP
  AVnet.com
  D/C 1106
   

  ▲OPA627AP
  FARNELL
   

  ▲OPA627AU
  AVnet.com
  D/C 1049
   

  ▲OPA627AP
  digikey
   
   
*Code* *Definition*
  Y Last digit of the year assembled (e.g. 0=2000, 1=2001)
  M Month assembled: (1=Jan, 2=Feb, 3=Mar, 4=Apr, 5=May, 6=Jun, 7=Jul, 8=Aug, 9=Sept, A=Oct, B=Nov, C=Dec)
  LLLL Lot Trace Code: May vary based on the size of the package and available space to put the characters. Some of the smaller packages do not have room for the full LTC and use an abbreviated version.
  S Assembly Site Code
  O Pin 1 Indicator
  (DEVICE1) Device Name
   
  -------------------
  All Malaysian plant
   

   

   

   

   
  Magnification: X80
   

  OPA827AID
   

  OPA211AID
   
   
  ---------------
   
  ▼China & E bay OPA627


----------



## calico88

How about the metal case like SM, BM or AM ?


----------



## EarlyBird

Hello,
   
  i recently received some OPA 627 APs. Does someone know if these are legit?  This is what they look like:

  
  I would be very grateful, if you did let me know what you think about these opa627. Thanks!


----------



## fjer

I bought a dual OPA627AU from eBay seller *hkaudioparts* for $8.99. I was of course highly suspicious, but they actually do sound good. They measure 48K and 51K (both ways) between pin 1 and 5, which seems legit.
   
  Top marking: BBOPA 627AU 9922
   
  Genuine?


----------



## shake

Quote: 





fjer said:


> I bought a dual OPA627AU from eBay seller *hkaudioparts* for $8.99. I was of course highly suspicious, but they actually do sound good. They measure 48K and 51K (both ways) between pin 1 and 5, which seems legit.
> 
> Top marking: BBOPA 627AU 9922
> 
> Genuine?


 
  No such thing as a daul OPA627xx as far as i know.


----------



## Avro_Arrow

It's two singles soldered to a single to dual adapter.
   
  Quote: 





shake said:


> No such thing as a daul OPA627xx as far as i know.


----------



## fjer

Quote: 





avro_arrow said:


> It's two singles soldered to a single to dual adapter.


 
  Exactly. 
	

	
	
		
		

		
			




   
  I just received a second one from the same seller. These measure 49K and 46K respectively, and looks exactly the same, except for another batch number (9914).
  I wasn't able to find anything about this seller anywhere on the internet, but I'm pretty sure he is trustworthy now (and cheap as hell, I might add).


----------



## Dutchi MerenGue

Can anyone help me confirm whether these are real or fake opa627ap's? i bought these a few months ago from a seller on ebay selling them as used and told me they came from a vintage reciever or something i forgot, they're from a 1992 batch i believe according to him, does anyone know?


----------



## Dutchi MerenGue

Quote: 





fjer said:


> Exactly.
> 
> 
> 
> ...


 
  thats who i bought mine from, i'm not knowledgeable enough to say if they are authentic or not, but they do sound good and warm which is what i was expecting from them and looking through his past sales and stock of whats currently on sale, it seems legit but i just would like piece of mind


----------



## oles

whether pr
   
  inting is genuine?; resistance between pin 1-5 = 49kOhm, original or not?
   
  Photo invisible ups: (


----------



## 405line

Bit late to this thread.
  I have received many 627BP's from http://www.ebay.co.uk/itm/1set-Dual-to-Mono-Op-amp-OPA627BP-OPA627-replace-NE5532-/261019559217?pt=LH_DefaultDomain_0&hash=item3cc5fa6531 they have always tested "true". I only took one chip out of the adapter to test...it was about 59.k pin 1-5 as has been the case on previous occasions from this particular seller...just thought you might want to know.


----------

