The TV 2.0 box does not have Cinch, but I think it has 3.5mm audio jack as far as I know.
There are 3-pin and 4-pin 3.5mm audio jacks while the 4-pin ones (3 black rings) are used mainly for laptops which use 4 wires (ground, left, right, mic) while the 3-pi ones (2 black rings) are used often in audio equipment (ground, left, right). I guess you're using a 3-pin 3.5mm jack to 2x cinch adapter. But I am not sure if the 3.5mm jack on the TV 2.0 box is 3 or 4 pin; as far as I know it's combined with optical S/PDIF too.
So you might check your cable or use another one just to try. Another (even better) option might be to use the audio out available on most TVs to hook it up to your amplifier. So connect your TV 2.0 box via HDMI to your TV and use the audio out on your TV to connect it to the amplifier. This wasy you might also get better A/V sync as most TVs cause some output delay and they also delay the audio out on those jacks. If you feed the audio directly from TV 2.0 to your amplifier the audio might be aut of sync with what's shown on screen by a few milliseconds.