You plug the radio into the amp. my first question is the radio has a amp in it I'm assuming, so your plugging a amp into the amp, sound like a problem for some reason. Another question, there is a 3.5mm input plug in on the radio. My fm radio earphone plug in my cell phone works quite nice plugged into the radio. the radio works with my cell phone but will it work with a small radio through the 3.5mm that I'm assuming is amplified more the the cell phone. last question the amp has a 3.5mm into it also ,will the cell phone and a small radio connect into that socket in to the amp., it's the line in for the mp3.