Stereo sound gone from time to time
 

Need to know if there is an stock amplifier or something between the stereo and the speakers. Thought my stock radio was going out and installed an aftermarket radio and it is doing the same thing. Every now and then while simply driving down the road, the sound goes away, radio is still on just no sound. Could be later on in the day or a couple of days later and the sound returns. Any ideas?

Sorry, 2002 Chevy K1500