An amplifier is the device that turns the low voltage signals from your source equipment into a signal with enough gain to be used to power a pair of speakers. The radio is selected like any other input on the amp but no other connection is needed other than a pair of speakers.

What does amp mean in sound?

audio power amplifier An audio power amplifier (or power amp) is an electronic amplifier that amplifies low-power electronic audio signals such as the signal from radio receiver or electric guitar pickup to a level that is high enough for driving loudspeakers or headphones.

Why do I need an amplifier?

Line level signals must be amplified (via amplifiers) in order to drive a speaker and produce sound properly. Amplifiers increase signal power and drop impedance to drive speakers appropriately.

Whats the difference between an amp and a receiver?

An amplifier is just a device that takes an audio signal and amplifies it so that your speakers can use it to play the audio. A receiver has an amplifier in it, but has extra functionalities such as a tuner, preamp, radio, input selection, volume controls, and more.