When I bought Cary Audio SLP 05 preamp, it sounded horrible out of the box. Billy Wright of Cary Audio told me to leave the preamp on with amps off and play something like a radio through the preamp continuously for 50-75 hours (Friday through Sunday). It made rather dramatic change which continued for next week or so with usual listening sessions. I don’t know if that will breakin the wires (interconnects might be but not speaker wire).
Good listening!
Good listening!