Since the amp is mono out, going in can only be mono. If you are only getting one L or R channel from your Aux in, you might have to get a adapter from stereo to mono.
I know, I know...... it is hard to understand stereo doesn't work with one speaker

And 3D doesn't work too well if your blind in one eye
haha, I have to explain that one to my fiancee all the time
