I just remembered that my Audio Research Ref 5SE used to require music being run through it for 10 - 15 minutes every time… even if it was powered on for an hour or two. Then it would sound notably better. Not a click and instantly sounded better… but over say 30 seconds every time. I thought I was crazy… I posted to a high end audio forum where lots of folks owned these and got many replies that They heard it also and it was a known thing… Happily, I just realized it does not happen with my REF 6SE.
So, I am thinking that is somewhat indirect evidence that initial breakin requires something flowing through it. Try lamp-cord… or cut up an extension cord to get around the ribbon cable issue.