I hessitate to sugges tthis, because if you do not understand and know what you are doing can get you seriously hurt or property damage. One very common problem that can cause equipment damage, malfunction, and noise if a poor service neutral to transformer connection or Main Bonding Jumper inside your service disconnect device. Real easy to detect with a voltmeter. Measure the voltage at the service entrance between L1-N, L2-N, and N-G
Proper reading is L1-N = L2-N, and N-G = 0.
Example if L1 and L2 measure 125 volts and N-G measure 0-volts life is good. If L1-N measures say 100 volts and L2-N = 150 volts you have an extremely dangerous situation that requires immediate attention.
I suggest you start by disconnecting your DC power supply. replace it with a battery, turn the main breaker off, and see if the noise stays or remains.