Usually that kind of problem is caused by a loose/old loading belt . The player takes the disc in but there isn't enough force to lift the mechanism into the right position . Player then can't "see" the disc and opens again . You can test this by opening the player and helping the laser...
Sorry that this happened to you .Unfortunately the older Rotel amps don't have output DC protection ,when they go faulty (and they will) you can say goodbye to your speakers😔 . I would never use an amp that has no output protection especially a very powerful one .
Well Im glad we had this conversation as I realized that I was only thinking of passive interaction and not how the pre amp cct would actually behave if it gets some of the other channels signal on its output (even though you constantly mentioned output impedance ) . This is why for me at least...
Exactly ,we want to minimize crosstalk ,because the 2nd pair of outputs on the pre amp are usually just wired in parrallell with the 1st ones so putting a resistor cable contraption on the output will give some crosstalk.
This can't be done properly with passive components , there are 3 options .1 use one pre out (left or right as most bass is mono )2. Might be possible to modify the sub input (depending on design ).3 Best option .Build a simple mixer pre amp.Making cables with resistors is a waste of time and...
Depending on the design of the pre amp using a splitter cable could link left and right together so your main speakers will now play mono . What pre amp are you using? Otherwise just use one pre out will probably be good enough .