~40hz buzz motor off rcas unplugged.

[HoneyBadgerRy]

Finally got the chance to put my car together and there is a buzz that plays through the amp with the motor off and the rcas unplugged. My only idea is bad ground, but I grounded the amp properly, so besides running the ground straight to the battery (very hard due to firewall space) I'm not sure what else to do.

It's not coming from the head unit because it is uneffected by the RCAs and it's not alternator whine because is happens with the motor off. My DD-1 picks the hummus up as 40hz and distortion, my ears pick it up as a low frequently humm.

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[Buck 5,000+ posts]

hook your amp up to a car battery outside of the car and see if you can produce the same result