Amplifier Problem

Hi there i have a MTX RFL805 amplifier and lately there seem to be high pitched whine coming from the amplifier. it will last for about 30 seconds and only happens when i start the car. When i shut the car off and restart it, the whine will not be there. I was curious what you all think is the problem. Thanks and any advice is appreciated.

it's happening when it's charging up the capacitors. i would venture to guess you can also hear it if you put your ear near the amp when it's playing/hitting high volume. first thing i would point at is dry solder connections on the board...... fairly easy fix for someone good with soldering/de-soldering.