[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.

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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...