it was Shenzhen ZhuoYuan Store but he doesnt sell them anymore.
i found the ones from lcsc are genuine but at 4.5€ a piece not really a bargain
I intentionally buy these chips from Aliexpress/Taobao for the fun of it. Trying to figure out whether they're fake is part of the fun 
Here's my OPA1612 from Ali (sorry for the residue, I didn't bother cleaning the chip):
Upon testing it seems to have a 150nA input bias current. That's over twice the typical (60nA) but less than the max spec (250nA).
OTOH I think the OPA1656 from the same store is probably fake. I couldn't even get it to work properly! (will add a die pic here soon)
Here's my OPA1612 from Ali (sorry for the residue, I didn't bother cleaning the chip):
Upon testing it seems to have a 150nA input bias current. That's over twice the typical (60nA) but less than the max spec (250nA).
OTOH I think the OPA1656 from the same store is probably fake. I couldn't even get it to work properly! (will add a die pic here soon)
What do you know, the parts did end up working like op-amps do right after we verified them to be original. Some sort of quantum Heisenbug, but more likely my crappy breadboard. This reminds me to build a simple fixture for testing a few basic op-amp parameters.
I don't replace op-amps in existing circuits so I can't compare. It is imperative that I know exactly what I have prior to building a circuit around it.
I don't replace op-amps in existing circuits so I can't compare. It is imperative that I know exactly what I have prior to building a circuit around it.
Just because they are not fake doesn’t mean they’re ”good” - they may be fall outs that don’t meet spec. For a lot of these op amps, the parameters which fall out of spec may not make a hill of beans difference in an audio circuit, but make them useless for instrumentation. The ONE you get could very well be in spec, because they fail entire lots if some percentage falls out. That’s how you get ungraded or “A” type TIP transistors that will actually take the 100 volts - they couldn’t sell the batch as the C type. Falling out of spec is how a lot of old ”surplus” found its way into mail order catalogs (and into Radio Shack) even in the way back years before there were fakes everywhere. You buy from places like that, you just have to deal with it. MOST audio applications just arent that demanding, and hobby projects tended to work no matter where you got the parts. Power transistors, we’ll, you always had to test those to be sure your project didn’t blow up. Op amps may have higher offset, drift, or noise, but in many cases so what?
But if the part NEEDS to meet all specs, just buy it from where you are supposed to and don’t try to cheat.
But if the part NEEDS to meet all specs, just buy it from where you are supposed to and don’t try to cheat.
I agree. There's just some extra fun in doing things this way . Besides it's very unlikely for these to completely break my prototype circuits. Some extra bias current, offset, drift or a missing zero in its THD won't affect me much, whereas a 358 disguised as a FET device would. And if my circuit fries the part I won't be as sad.
With power components you can tell if it's a fake by the die size. Fakes are tiny, originals are large. Of course this doesn't eliminate the possibility of discarded out-of-spec batches either.
. Besides it's very unlikely for these to completely break my prototype circuits. Some extra bias current, offset, drift or a missing zero in its THD won't affect me much, whereas a 358 disguised as a FET device would. And if my circuit fries the part I won't be as sad.With power components you can tell if it's a fake by the die size. Fakes are tiny, originals are large. Of course this doesn't eliminate the possibility of discarded out-of-spec batches either.