are these op amps counterfeit? (4558D)

[darbycrash]

forgive me if this is not the right part of the forum to post this question (and feel free to move it where it should be of course). these JRC4558D op amps look odd to me, is it possible that they are fakes? i really appreciate any insight you can offer, thanks.

[mozz]

Print looks too simple. See if it comes off with alcohol.

[R.G.]

Is it possible? Sure. Anything that can be counterfeited for a profit probably will be.

As mozz says, see if the printing wipes off.

Beyond that, there is a fundamental problem with fresh stock semiconductors, even by the real, true maker. Semiconductor makers are riding a tiger in terms of silicon manufacture and processes. The real money in semiconductors is in the chips that are one generation back from the most-current, bleeding-edge chips. This is where the every day processors and memory chips sit. The silicon foundries have to compete to get to the bleeding edge, or they will be out of the competition when the bleeding-edge becomes the everyday. Older silicon processing fabs are relegated to older and older chips, including analog. As a result, the analog chips also ride on an ever changing silicon process. So the makers have to migrate their analog stuff on new silicon process fabs, too. They try to make the resulting chips at least meet the datasheet specs, but they are not guaranteed to be crude enough to have exactly the same off-spec performance as the earlier generations.

In musical electronic, we sometimes pick old part numbers to get those same pleasant accident off spec things. But the manufacturer will label anything from new process lines that meets just the datasheet with the old number.

Best advice? Put a couple of those chips into sockets in your circuits and see if you like the sound. This is probably more important than the number printed on them.