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PostPosted: Fri May 30, 2014 3:19 pm 
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Muriel
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Hi,

mundian to bach ke rahi - beware of the boys (who fake Op-Amp's). This is the theme song for this week.

https://www.youtube.com/watch?v=6GM-4CFHlmA

Okay, of course we only buy from reputable sources, we screen our parts scrupulously. Even so, occasionally something slips past. It is amazing how dedicated the fakers have become to their craft. If they applied so much care to faking US Buck's they could put the Federal Reserve out of business.

So the last few days I was chasing my tail bout what turned out to be re-labelled Op-Amp's. They were supposed to be J-Fet input, nothing too fancy. Still, someone went through the effort to buy and un-reel reels worth of TI NE5532 and relabel them as something else, relatively inexpensive and offering merely modest performance and re-reel them. We are talking to the source, who disbelieved our reports.

The grinding off the top was fine enough a grit that one seriously doubted oneself in the identification as relabelled. The laser etching was good enough that it took a real part side by side to see the lack of quality in the laser engraving, the markings etc.all conformed to the latest information available on line.

I had a worse case with some of the supposedly same parts bought of e-bay to bypass delivery times. They shorted out and blew up my experimental PSU boards which themselves where full of parts that had long lead times in volume and I had already gotten all their sample stock...

Lucky enough we caught this before any actual product shipped out with these chip's, we spotted it in the final checks before we send the parts off to the factory. So now we need to get replacements (real ones) and hence production will fall behind. I can imagine many places where the Boss's first question would have been not "How long for replacements" but "Can we use these anyway?"...

Hence, if you buy an Op-Amp, even a fairly generic but audio part that sells at a modest premium over a 5532, you may have gotten a 5532 instead. And if you buy some "High End" gear with supposedly those chip's inside you may also have gotten 5532, as the manufacturer may very well buy from the same source as we do.

Also, cute conspiracy theory of mine. If you wondered why so often reports on the sound quality of a given Op-Amp vary so much, I wonder how often the supposed "Marvellous Sonic Wonder Op-Amp" bought cheaply of E-Bay and that failed to please was actually a relabelled 5532 or TL072?

Anyway, I spend the last two days designing and making (well, I had the lab assistant do the hard work of making) an Op-Amp test Jig with interchangeable ZIF sockets for DIP-8, SO-8, SOP-8, TSSOP-8 to once and for all get a way to weed out the fakes, which is how I was able to confirm which are fakes and which are real. It attaches to an AP2 of course, for measurements (and has the option to set the Op-Amp to 60dB Noise/Distortion gain so we can see what is going on down below) plus has sockets for other test gear ('scopes and meters - so we can spot undue DC offset and oscillation).

Of course, this Jig can also be used to look deeply into the distortion, noise etc. performance of Op-Amp's and while testing samples of all the reels we stock I already found interesting stuff that might help to correlate the subjective sound quality. So, now I know which ones are fake, which ones are real and which ones are really interesting... Next weekend I'll have the Assistant add a few more switches so I can test more cool things on Op-Amp's.

I guess I should thank the fakers for making me get up of my fat A$$ and come up with ways to measure the stuff that normally is lost in the noise floor of the AP2... But honestly, I just want to design in the hot Op-Amp du jour make sure I get it to sound the way I want and then rely on the distributor to f.c.u.k.-i.n.g. do their f.c.u.k.-i.n.g. job and sell me real parts.

So T.G.I.F. and I propose a mandatory death penalty for people faking electronic parts and severe penalties for any found handling falsified goods. I actually have a job to do, rather than doing their f.c.u.k.-i.n.g. job!

Ciao T

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"For a successful technology, reality must take precedence over public relations, for nature cannot be fooled." Richard Feynman


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PostPosted: Fri May 30, 2014 4:22 pm 
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Dog
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Joined: Tue Dec 14, 2004 12:26 pm
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Location: Lisbon, Portugal
I don't buy that kind of stuff on ebay and for capacitors (dangerous territory too), I have a few sellers saved on my favorite sellers list, from who I buy caps for many years.

Anyway, some people really ask to be cheated.
Who is going to buy fancy japanese caps for cheap, in China? Does it make sense?

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"Any intelligent fool can make things bigger, more complex, and more violent. It takes a touch of genius - and a lot of courage - to move in the opposite direction." Albert Einstein


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PostPosted: Mon Jun 02, 2014 10:29 pm 
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Sheep
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Joined: Wed Jan 19, 2005 6:12 am
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Hi T,

why do you don´t buy directley from the manufacturer?

BTW: "Dieses Video ist in Deutschland leider nicht verfügbar, da es Musik enthalten könnte, über deren Verwendung wir uns mit der GEMA bisher nicht einigen konnten."

MFG Carsten


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PostPosted: Tue Jun 03, 2014 10:14 am 
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Muriel
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Joined: Thu Jul 26, 2007 5:45 pm
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Hi,

carawu wrote:
why do you don´t buy directley from the manufacturer?


If you only buy a few reels, many manufacturers do not sell to you direct. You need to be Apple or Samsung for that. Additionally they often have little stock and long lead times.

So one needs to buy from Distributors. These may be "authorised" distributors that have a contract with the manufacturer or just generic distributors that carry tens of thousands (if not more) distinct different parts. Or they may be brokers.

In fact, if big - multi-line distributors are out of parts in demand (say several manufacturers try to buy several reels of the same part and they only have a handful in stock, common for audio parts) they may at times get stock from brokers. Some of the brokers may be tainted. You will only know when you have the devices and only then if you can test rigorously.

And this is likely what had happened that time and no, we could not wait the 12 Weeks lead-time originally quoted, neither I think could some others. :grin:

Ciao T

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