2017-01-06, 10:39
If your amplifier is smart enough to detect the number of speakers you have connected, as jjd-uk suggests, it should automatically downmix a 5.1 source to stereo on your behalf. Make sure however to connect your HDMI/Optical cable directly to the amplifier, not the TV first, as some TVs only output stereo over HDMI. So if you do upgrade to 5.1 speakers in the future, you may still only get 2.0 stereo going to the amplifier (from the TV).
