Magsafe 3 interference in the 3.5 mm headphone jack

lfbitt wrote:

1. Hello,

I can hear a static/interference noise in my headphones/earphones when simple video processing/rendering is being carried out by my macbook pro 14" AND it is connected to the magsafe 3 power cord. Here is how to reproduce it and what I've tried to test it:

Go to a silent place.

2. Plug the magsafe 3 cord to the macbook pro and plug it to the outlet.

3. Plug your earphones/headphones to the 3.5mm jack.

Open a webpage that contains somewhat heavy (but not that heavy) graphics with chrome or safari. Example webpage: www.apple.com1. . I can hear it even in this page where I'm writing this question.

2. Scroll the page down and up to hear the noise in your headphones.

This noise can be heard in other situations where rendering occurs (e.g. open the maps application and roll over the map). If I unplug it from the magsafe, the noise disappears. If I reduce the Built-in display refresh rate from Pro-motion to other refresh rate, the noise apparently is reduced.

If anyone can try this and find similar behavior, maybe it is a design issue. If not, I will take my (brand new) macbook pro and power adaptor to an authorized service.

Thank you

Are you using the 3 prong grounded plug...(?)

I would start there:

Power Adapter Extension Cable - Apple

they are all inter changebale if you have an old extension cord

lfbitt wrote:

macbook pro 14"

Thanks for your kind suggestion. I was using the 2 flat parallel pins that comes with the power adapter. I tested the grounded prong from my old macbook pro and noted no difference.

You can try a Safeboot to sort anomalies

—SafeBoot How to use safe mode on your Mac - Apple Support

Takes a bit longer to get to the login screen, does a quick disk repair before it fully boots up, and certain system caches get cleared and rebuilt, including dynamic loader cache, etc.

Login and test. Reboot as normal and test. Caches get rebuilt automatically

—Test issue in another user (or guest user) account Set up users, guests, and groups on Mac - Apple Support

This will tell you if it a universal issue or isolated to your user/admin account. 

Uninstall all third party apps that are Cleaners/Optimizers/VPN/Anti-Virus

all known to cause issues on the macOS

if no insight or resolve—

Call Customer Support (800) MY–APPLE (800–692–7753)

or on line Apple Support