Connect Mac mini to Echo dot via 3.5mm Aux

Is it possible to connect the echo dot to Mac mini via 3.5mm cable? I can easily connect it via bluetooth but the interference is awful (that's also annoying - not sure why its so bad - the echo is on top of the Mac mini!). So I wanted a wired connection. But it doesn't play music - its muted. Not sure how to use it as a speaker for the Mac mini. Any ideas anyone? thanks