Dc-Dc intelligent usb noise problem.
Hello, I'm having a weird issue with my power supply. When I hook the power supply up to constant hot I get a very unusual noise. I can't really explain it, it's a really high pitched and crackling sound. I've been doing car audio for a while so I'm used to troubleshooting ground loops and alternator whine. This isn't like that at all. I ran new power and ground direct to the battery and as long as the laptop is hooked to the supply I get that noise. I rerouted everything to the battery and powered it up and it's still the same issue. Absolutely perfect running off the laptop battery. I brought my second battery to the car and powered just the supply to the laptop and it still did the same thing.
I'm at a loss. I've changed every single cable in the car.
Anyone have an idea?