But my basic idea I had was wrong:
DVD player connected to the scart cable and the adapter to the TV. Then on the two RCA jacks to transfer the sound to the stereo amplifier. Thus, one would set the tone of TV and DVD player to the audio system.
it does not work. Either TV or DVD sound to the switch to IN or OUT must be set. The simultaneous pass-through is not possible.
Shame
Nevertheless, the product is absolutely perfect.