i thought this guy was mistaken because i tried to decipher the text in the datasheet and i think he might be measuring incorrectly and the behavior of the ESD protection diodes is more complicated than what he expects
>The item is fake or not genuine. The genuine opa1612 ic has to test positive for diode at pins 2 and 3. These diodes are incorporated in the ic circuit as a way to protect against voltage overloads. The opa1612 ics that were shipped do not have these diodes incorporated, so they are not genuine at all.

then i saw this guy with a 200hkz square wave on an oscilloscope who also mentioned diodes
>Fake. This is not opa1656, but NE5532, according to the frequency characteristics of the Chinese 5532, even the diodes between the 2 i3 legs are ringing like in the 5532, I do not recommend buying here, 100 percent will be found, think for yourself whether you need microcircuits 10 times more expensive, but in fact the same 5532

so what is this diode thing that apparently can be measured relatively easily to see if the op-amps are crap or not?

btw some of the other sellers are clearly different sellers (not samefags with a different account) and they get good reviews
https://www.diyaudio.com/community/threads/opa1612-from-aliexpress-no-counterfeit-but-why-so-cheap.399994/