It’s possible to put two difference ICs into the the 14-Pol DIL-Socket. A TL074 or a MC33179DG. If the kit was bought directy via Schalltechnik_04, it contains both ICs.
The TL074 is a J-FET-OPAMP, the MC33179DG BiPolar-OPAMP.
The MC33179DG produces less noise and sound a bit fatter and crispier. Since the MC33179 is widely available as SMD-Type, the kit contains a SMD-to-DIL-Adapter PCB.
NOTE: If you ever put the SMD-to-DIL-Adapter into the socket, the sockets’ contacts get bended. From this point on the TL074 won’t fit into socket anymore!
Align correctly! “bar to bar”
…and take the MC33179DG. Put it in the right place and solder the coated pad to the relay pin. Afterwards solder the other 13 pins/pads together.
The SMD-to-DIL-Adapter PCB can be easily separated from the main-pcb by bending it at the breaking points.