I'm using a 15' Mid-2012 Macbook Pro (macOS Sierra 10.12.4) connected via the headphone port on the MBP to the back of my Logitech z906 Subwoofer's RCA Input. Been using this setup for over 4 years without any issues, but then suddenly today there is a huge amount of static as soon as i play any sort of audio on the MBP When i connect the speakers with the same RCA jack to my iPhone and play music there is no static on the sound system. This leaves me to think that the issue is with the MBP. What's odd is that when i connect my headphones to the headphone jack on the MBP and play audio the static is sometimes there and sometimes not. The MBP is well out of warranty so i just wanted to get an idea what could be the issue and/or things i can try before taking it into the apple store. Would appreciate any advice, thank you.