How do you play music from your phone on a guitar amp?
You don’t use a direct box for that. If your amp has an “aux” input then you need a male 3.5mm to male 3.5mm cable. You connect one end to the headphone out on the phone, and the other end to the aux input on your amp. If your amp doesn’t have an aux input you need one end of the cable to be 1/4″. Easiest way is to still use the 3.5mm to 3.5mm cable and then an adapter like this.3.5mm Stereo Jack to 1/4 Stereo PlugIn this situation you go into the normal input of your amp, like where you would plug in the guitar. Most newer solid state amps do have a aux input now though.