Electrical hum through earphones/grounding issue?

Question

Electrical hum through earphones/grounding issue?

Reached out a few days ago but didn't get much help and since then I've done some more testing so I thought I'd ask again.

Earlier this week I bought a Mac Mini 2023 m2 pro, everything is working fine except I get a quiet electrical hum through my earphones. I'm assuming its to do with the computer not being grounded (I'm in the uk and I'm not sure if its supposed to be or if I have a fault) as when I touch the computer or the metal on the keyboard it's connected to the hum stops. Even if the mac isn't switched on, just plugged in, the sound persists. I've determined that its being caused by the machine itself as I've removed everything and plugged it directly into several sockets and I still hear it.

It effects my original earphones I used on my old computer (late 2012 Imac) that plug into the headphone jack and a cheap pair of USB C earphones I picked up today. Strangely it doesn't seem to effect a pair of official apple earphones, but it may just be too quiet to hear. Trouble is I need a mic and that set doesn't have one.

I don't live near and apple store and don't really want to have to send it for repairs only to be told that this is just how the mac minis are. I've heard that usually the computer gets grounded though the connection to your monitor but I don't believe my monitor is grounded either as it has a plastic third pin. If this is a normal thing then I can put up with it until I upgrade my monitor sometime in the future but if I do have a fault then I would rather get it fix as soon as possible.

Mac mini (2023 with M2 Pro)

Posted on Feb 18, 2023 02:06 PM

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Answer 1

K_Faith

Community Specialist

Feb 20, 2023 12:30 PM in response to andrewdoesart

Hello andrewdoesart,

Thank you for reaching out to Apple Support Communities, and we'll be happy to help in any way we can. We understand you're having issues with an electrical hum on your mac when using headphones. As it doesn't seem to affect the Apple headphones, it is possible that the issue is with the headphones you're using. If it persists with other headphones, we recommend having a technician have a look to see if there is a hardware issue: Find Locations - Apple

Check out this article for more information on what to do before you take your device in for service: Get your Mac ready for service - Apple Support

We hope this helps.

Cheers!

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Answer 2

Feb 20, 2023 01:44 PM in response to K_Faith

Thank you for your reply! I've pretty much come to the same conclusion as you and will probably end up trying to take the computer to an apple store.

I can't be 100% sure as I don't have many headphone to test but I seem to only get the hum with earphones that have an inline microphone. The label on my old earphones (with inline mic) says they are "type: hmz17-ctia-3.5" if that means anything. The usb c ones I tested were a cheap kodak pair with inline microphone. Both have the quiet hum but other all audio is fine and normal, I believe the microphones work normal and the hum isn't picked up on the mic. The hum is also not effected by volume settings. The apple earphones and a random pair of earphones I found, both 3.5mm style without microphones, don't appear to have the hum.

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Answer 3

chuckbl

Community Specialist

Feb 20, 2023 05:03 PM in response to andrewdoesart

Hello andrewdoesart,

Since this is occurring with headphones with a microphone via both USB-C and the 3.5mm headphone jack, having your Mac mini physically inspected would be the next step. They'll be in the best position to look into this behavior further.

Take care.

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Electrical hum through earphones/grounding issue?

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