These buggers are known to clip but its most likely an issue with the power cable. Does it happen when the car is parked (still) ? What was the issue with the first amp? Can understand a problem with one amp... but 2 of them one after the other indicates something else.
1) Throw away the condensor!
2) Are you using a Pioneer HU ? If so it will need grounding.
3) What car? Some cars you have to lay the wiring extremely carefully(power one side, RCA's another)
4) Lastly check the RCA cables (interconnects that have been used), if they are some bakwas then invest in some better ones.
O/T : You could take it to the 75.4 King of the South aka Nitrous Anna
