2012 Mini - sound problem / static

Try plugging the audio components into a separate power strip/outlet from the computer/computer peripherals. This solved a similar problem for me with a external usb DAC and active monitors.

lamerica80 said:

Ok ive noticed the interference stops when i unplug the USB from one of the externals, even though the drive is still on (running from external power source).

Anyone have any ideas at all?

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Don't quote me on the specifics but I thought I remember reading that there was a problem reported a while back about RF noise leaking from USB 3.0 cables and/or devices when they were plugged into the some late-2012 Mini's USB 3.0 ports. I believe it effected 2.4Ghz and Bluetooth devices including the Mac some Mac Mini's internal Bluetooth Tx/Rx radios. It primarily effected the useable distance for the Apple wireless keyboard and mouse/trackpad. There was a shielding repair kit available to fix the Bluetooth issue for Mini users who experienced this problem. (Since then I believe Apple has have improved the shielding for the Mini's Bluetooth radio.)

For interference problems with all other devices there was a solution to use better quality shielded USB 3.0 cable and better shielded USB 3.0 devices (external HDs, etc.) If this interference problem is what is effecting your sound you could use the above solution for cables as well as using higher quality shielded audio cables and better shielded speakers.

This noise issue from RF interference is not an uncommon problem. I know from experience that some cell phones can transmit interference to computer speakers. A few years ago I used to hear clicking and static immediately before my cell phone rang or before it received text messages. This happened whenever the phone was near my computer speakers. When I changed to a different phone the problem went away.

lamerica80 said:

Thanks for you reply!

I have noticed the static stops the second i un-mount the harddrive even if the USB-cable is still plugged in and the drive is spinning.

This tells me the problem happens when the computer is sending information through the USB cable. All the ports are the same. Its a USB2 cable btw.

I will try with a different USB cable and see if this helps!

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This tends to be a USB 3.0 problem and not as much a USB 2.0 problem. It could be the result of using USB 2.0 instead of USB 3.0 spec cable to your external drive. The key is to effectively shield the EMF/RF noise that is being emitted and/or absorbed like an antenna by one or more of your cables. Try a very high quality "shielded cable" designed for USB 3.0. If the noise persists also try a shielded mini plug audio cable if that is what you are using for audio (I have a Monster brand cable of this type for mini audio jacks). If you are using HDMI for your audio/video then use a high quality shielded cable with those round magnetic filter nobs near the ends (I have seen these available on Amazon). I read that the RF leakage problem could also be made worse if you are using a cheap external drive enclosure that leaks EMF/RF noise.

Just a thought...This make me wonder if some of the video color problems, interference and snow issues that some late-2012 model Mini users still are reporting to have (even after the 10.8.2 ML update but only when they use HDMI cable connections) could be related to this same USB 3.0 EMF/RF leakage issue. If so then upgrading their USB 3.0 and/or HDMI cable could be the answer.

Let us know if you find a cable that solves the problem. When I have looked for USB 3.0 cables with better shielding I haven't found one that specifically states that it has improved shielding that eliminates RF problems.