spikes coming out of turbo card(ESI-4000)

It seems that i will get these spikes out of the esi 4000, but they only come out of the turbo card sub outs. I am doing alot of filtering on the sounds but the spikes dodn't happen every time, like 1 every 2 mins to 5 mins and somtimes it gets real bad. it is nothing to do with the power. So if you have any ideas i would like to hear them. steele_a@hotmail.com