So my aux input died, I got another headunit for free, but the aux on that is distorted as hell.

Is it feasible/possible to buy a switch and sit them in the glovebox with a cable, and have the car antenna go through the switch too? So when you want radio, you put the switch to use the antenna, then, when you want to plug in a phone/ipod, you flick the switch over and plug in your phone?

Pic related, I sent it to a friend explaining this if that helps. I found out after drawing it that headphone jacks are analogue so I don't need a dac though, but maybe some sort of amp?