Anyone heard of these “isolation amplifer” ICs from vintage Kenwood equipment?

Hi all,

I have a few 90s Kenwood active crossovers meant for car use and they have an interesting IC(s) right at the input to cancel out common mode noise.

They are given different names in different models and googling the part numbers doesn’t turn anything up.

They can be found in the service manuals for these two:

https://ia902301.us.archive.org/20/items/manual_KEC300_SM_KENWOOD_EN/KEC300_SM_KENWOOD_EN.pdf

Page 9, given as IC1 “lNH-02080”

And for this model

https://ia902308.us.archive.org/32/items/manual_KEC301_SM_KENWOOD_EN/KEC301_SM_KENWOOD_EN.pdf


Page 6, given as IC2 “NH384”

Anyone heard of these, why these rather than the other types of op amp (upc4570) used in these crossovers?