Anybody ever attempted replacing a socketed op-amp in some audio device with a circuit board plugged into that socket? There are discreet component opamps that are available to do that if that is what you are into, but is it common to say add an active filter circuit into an existing product with this method? I was looking at a Fosi box x5 phono amp that has no subsonic filter but does have socketed opamps for users to fiddle with. Pulling that op amp and plugging in a small PCB with the same op-amp and some filtering caps/resistors around it might be a non intrusive way of modding the original circuit to incorporate added filtering stages to try out.
Yes, for instance its how you get non-DIP opamps into old equipment, use a break-out board that plugs into the IC socket. I've thought about (but not actually done) putting two SMT NE5534A's onto a PCB than can plug into a dual opamp socket, for instance.