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Luna Murasaki

macrumors regular
Original poster
Jun 24, 2020
127
303
Purple Hell
I have noticed a noise lately coming from my computer setup. The noise is high pitched enough that I suspect that normally only young people can hear it. I am 37 years old and I can only hear it with my right ear - not my left. It is loud enough to be hurting my ear and is leaving a lasting ringing in my ear when I leave the room, so I am worried it is causing hearing damage. I am also worried it could be bothering my lizard who is in his cage next to my computer desk - I don't know what frequencies they can hear.

I went crazy trying to figure out where it was coming from and even ended up buying a whole new KVM switch. But it isn't the KVM switch, it's my new USB-C Magic Keyboard (White with Numpad). The noise happens only when the keyboard is connected wired. When operating wirelessly, the keyboard is silent. I also bought a Magic Trackpad, but the trackpad doesn't have the issue.

I am wondering if anyone else has this problem and has any idea what to do about it. I can't operate the keyboard wirelessly because then it won't work with any of the other devices on the KVM. I HAVE to have it plugged in.

Maybe an alternative would be to use a USB bluetooth receiver? I could plug that into the KVM switch and then pair the magic keyboard with the receiver. Then I don't have to operate it wired. The problem with that is that I don't know if any such product would work with the Mac, especially when it comes to Touch ID. I also don't know how the OS would handle it when the receiver is suddenly plugged into another machine when I switch inputs on the KVM.

One thing that would help me is if other people with this keyboard could listen to it and tell me if they are hearing the same noise when it is plugged in. Maybe you guys could do that and mention your age and what version of the USB-C Magic Keyboard you have (with numpad black, with numpad white, or without numpad). That would tell me if this is a defect in this particular unit or if it is a normal part of this device.

I am so exhausted. I appreciate any help.
 
I just bought the USB-C keyboard and trackpad and I noticed the noise from the keyboard also. I want to leave the keyboard plugged in to my docking station so it can be used with different computers. I'm trying to decide if I should return it for a new keyboard or if they will all have the same problem.

It seems like the noise starts up when the battery is fully charged. I wonder if a special USB cable without the 5v connection would work? The other thing to try would be to remove the battery.
 
I just bought the USB-C keyboard and trackpad and I noticed the noise from the keyboard also. I want to leave the keyboard plugged in to my docking station so it can be used with different computers. I'm trying to decide if I should return it for a new keyboard or if they will all have the same problem.

It seems like the noise starts up when the battery is fully charged. I wonder if a special USB cable without the 5v connection would work? The other thing to try would be to remove the battery.

I didn't think the battery on something like this could be removed. I can say that plugging it into my surge protected power strip next to my desk using a USB-C charger and a completely different cable had no effect on the problem at all.

Other weirdness I noticed is that turning on caps lock seemed to have a noticeable effect on the noise, either changing the pitch or providing temporary relief from it altogether (though maybe it only seemed that way because of a pitch change outside my hearing range). If your caps lock key is doing something similar then maybe we are indeed talking about the same problem.

It's been a month since I created this thread. My dad purchased his own USB-C Magic Keyboard (black with numpad) and it didn't have this problem at all, while mine still did when plugged into his equipment. That inspired me to seek a replacement. When I plugged the replacement in and left it that way for about 6 hours, it once again started issuing the same noise. My boyfriend suggested it might be related to a problem with power fluctuations at that end of the house that for some reason only the white magic keyboard with numpad was sensitive to. I was going to try plugging it into various power strips elsewhere in the house with the USB-C charger, where for each one I would leave it there overnight to give the noise a chance to show up. The first place in the house I tried, it didn't trigger the noise. I then hooked up the keyboard with my KVM switch again to use it for the day. It has not made the noise since.

I don't know if that process somehow magically "healed" it or if the replacement keyboard was somehow less affected by the issue so that it quickly went away on its own. I can't make sense of the experience at all, but maybe sharing all this will give you what you need to fix the problem on your own keyboard. 🤷🏻‍♀️ Maybe let me know if you resolve the issue yourself and what worked. Even with the problem seemingly behind me, I can't help but to be curious.
 
I found a post online where someone with an older magic trackpad reviewed a "USB Power Blocker" in the hopes that they could use it plugged in to a KVM switch without charging the battery to prevent battery swelling. They reported that if they block usb power the trackpad does not communicate over USB.

My keyboard also gets quieter when the caps lock light is on.

Another theory I had was that the keyboard may prefer charging at a different voltage. I was using a USB A to C adapter to plug the keyboard into my CalDigit TS3 Plus's USB A 2.0 port, which does not support the USB-C PD additional voltages of 9v, 15v, etc. I used the included C to C cable to plug the keyboard directly into my Macbook but I still experienced the same noises.

I found some comments online about "coil whine" in other devices that indicated it could go away with time. I'm going to try leaving the keyboard plugged in over the weekend and see if it makes any difference.
 
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