Amplifier problem. hello everyone . i have a dvd player (LG) and it has six outputs(5.1 system).

Question

hello everyone . i have a dvd player (LG) and it has six outputs(5.1 system). i connected the output (only the front left and right)of this this dvd player and gave as an input to my TV. The output of Tv(audio) i gave to an amplifier. My amplifier is an old one and has AUX in Left and Right as input.Now my problem is yesterday i tried to watch a movie. The video was good but the audio was not coming specially the dialogues but could hear the background music.after this i put some other dvd and everything was fine with that dvd , audio and video both.and when i removed the amplifier and connected the output of my dvd player to speakers i could hear the audio(in the first dvd).i am not able to find a solution to this problem and kindly require ur assistance.