What makes you think there's a chip in these?
i don't know the proper name for it , but it's that where the volume control is !!
There might be a small printed circuit board, but I expect the volume control is just a potentiometer (a variable resistor). That's standard for headphones.
. +1. If there were any electronics that needed power, it would require a bias on the amplifier's headphone output or an external power supply.. How are the wires physically joined to the pot/board? Probably soldered.
If these were noise-cancelling headphones, there *would* be some electronics there, and a battery to power them... but they aren't.