Is a break-in period required? If so, how long?

I was trying out the PCAs today and after a few CDs I basically decided they were not close to my prior cable - which makes sense because the other was more expensive and silver. So I switched back.

The thing was the PCAs just sounded slow - not tight, especially in the bass and drum kicks, and the highs were just too edgy.

Well if somebody wants to buy these PCAs from me let me know I have four .5M pair.