But now it comes even better: I really wanted to use right away, I decided to fast another RCA connector to be soldered. When I cut the cable and stripped I saw that the inner conductor is a rigid wire. No wonder that this is the same broken !!
Even at 1.50 euros Cinchcable the inner conductor is designed in a flexible way (consisting of many thin individual wires) and not as thick wire as with permanently laid cables in the wall.