The connections:
Raspberry Pi to amplifier: goes by the tv connection
tv to amplifier: stereo (red-white) cable
dvd to amplifier: single side of a stereo cable, because i don't have a coaxial audio cable (not needed anymore, this works perfect)
additional phone for sound: 3.5 mm to stereo cable
I've bought this set for about 20 euro at the local fleamarket. The sound is a lot better than the build-in stero of the tv, also in the commercials you have the idea of "being there" while the tv gives only stereo to the amplifier.
