99 chrysler town and country?

I installed a after market radio into a 99 chrysler town and country , it did not have a radio at all in it,, It has the infinity sound system from the factory witch means it has a factory amp,, I hooked it up and works great until you try to turn it up load then the amp starts kicking on and off,, I am a certified tech and I know how to hook a radio up, So no stupid answers,, Like i said it plays good on low, but put a song or cd in that makes some base and it kicks on and off,, Has anyone ran into this problem before,,, Just curious does the Amp/power antenna wire put out enuf volts to keep the relay on,, Im thinking that it don't and when the base hits the voltage may drop just enuf to kick the relay off,,, ,