Whining noise

Ok here i go my headunit is a Clarion - DB345MP. I am have a 2 amp setup. 2 channel 400 wattcoustic amp for my subs and 4 channel 320 watt amp for my commponet speakers. the whining didnt start until i added the 4 chann amp. the amp has its own power cable to the battery and its own ground. i have power cables ran on 1 side of teh vehicla and signal   wires on the oppisite side. now when i unhook the 4 chann up i get a vibrating sound from my subs which i didnt get before. but when everything is hooked up i get a whining sound. its low when the car isnt on but when car is on the whining increases as i accelorate. vehicle 1990 blazer

i have the rca ran with the hu wires and speaker wires ran on the passenger side of the vehicle. havent had time to repostion the ground wires had to put new brakes on my brother surburban. i found a kink in my rca but i had a smaller pair and hooked it up so the smaller rca ran from output from the 4 channel amp to the input of the 4 channel amp and the whine still present. ill reply when i get the grounds secure. another question the connection for the 4 channel amp where you run all the hu wires to has a ground on it can i just ground that to where i ground the amps? or do i have to run the ground from the hu?

ok i got a new rca to run from the hu to the 2 channel amp and regrounded the amps to a clean location. im still getting a whining noise from the the speakers hooked up to the 4 channel amp. when i unhook the 4 channel amp the whining noise stops. also got red of the vibrating from the subs. dont know what to do about the whining noise tho

See this recent post for info on muting plug, and isolate the source that way.  First, pull the RCAs from the 2 chan, pull the RCAs from the 4 chan, then plug the original (from two chan amp) RCAs into the 4 chan amp front.  Check for the noise, then plug into rear, check.   Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.