iMac (Mid 2011) headphones audio out ticking

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Level 1

25 points

iMac (Mid 2011) headphones audio out ticking

My iMac has served me well over the years, but now something happened. After moving the computer from a room to another, the audio out started a ticking problem. When I load Windows, it ticks indefinitely once per 1,5 seconds. When I load OSX, it ticks a couple of times until sound is not used anymore. Only if normal sound is played, it starts ticking for a while. Volume setting doesn't affect the ticking. I noticed some others encountering the same problem but couldn't find a solution.

Probably has nothing to do with hard drive. The sound is from the audio out port. I tried removing USB devices etc. if they would interfere, but the noise remains. There's nothing wrong with the playback audio itself. It's just the annoying loud ticking noise that keeps sounding. If I go to Device Manager / Sound / Cirrus Logic CS4206B (AB 32) and disable that, the ticking stops. But then the playback audio also stops.

Does anyone have guesses as to what happened? Some audio circuit condenser was damaged while I moved the computer? Is there some solution besides buying an external audio interface?

iMac, OS X Mavericks (10.9.2)

Posted on Sep 5, 2016 2:04 AM

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Answer 1

den.thed

Level 10

92,410 points

Sep 5, 2016 6:20 AM in response to jiokay

Check your outlet and all power cords for proper polarity and ground.

Then if your still getting the tick.....

1. Quit all audio applications/programs.

2. Disconnect all 3.5mm and USB audio devices from the iMac.

3. Disconnect all other unnecessary USB, FireWire and Thunderbolt devices.

4. Disable all audio applications/programs that are set to Automatically Start at sign-in/login.

5. Reset the SMC, as per > Reset the System Management Controller (SMC) on your Mac - Apple Support

6. Reset the NVRAM, as per > How to Reset NVRAM on your Mac - Apple Support

Now then, slowly start reconnecting your devices one at a time and test it for awhile with each added device.

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Answer 2

jiokay Author

Level 1

25 points

Sep 5, 2016 8:43 AM in response to den.thed

I did all that. No use (I had already confirmed that it is not driver or application related as it suddenly happens on two different operating systems). Without any devices the ticking is there. Any other suggestions?

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Answer 3

jiokay Author

Level 1

25 points

Sep 9, 2016 4:42 AM in response to jiokay

Extremely weird. I got a new external USB audio interface. Plugged that into an active USB hub (or directly to iMac, doesn't make a difference). Plugged headphones to the new audio interface. And the same ticking appears (slightly less volume)! And this happens when no other USB devices are attached to iMac and ethernet cable is also disconnected! And indeed it stops if the driver is disabled, same thing in Windows and OSX.

What can I possibly try still? Can the power outlet have some faulty every 1,5 seconds repeating power surges? That's the only thing that is connected and that is different from the previous room the system was located in.

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Answer 4

den.thed

Level 10

92,410 points

Sep 9, 2016 6:47 AM in response to jiokay

I can't think of anything that would cycle on/off or at that freq. off the top. I would check to see what other devices there are on that circuit or on that leg of the main. If also could be coming in on one leg of your main power service and you moved from on leg to the other.

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Answer 5

jiokay Author

Level 1

25 points

Sep 16, 2016 7:16 AM in response to den.thed

Ah, got this resolved. I didn't install the table by myself so I didn't think of it earlier. Right below the iMac, there is an electric control unit for the automatic table's lift mechanism. This unit controls the motors that lift or lowers the table by button press. When I removed the power cable from the control unit, the noise stopped. So the unit has very poor shielding.

The audio cards apparently programmatically activate the amp and/or DAC, thus eliminating external electromagnetic interference when the driver is not active.

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Answer 6

den.thed

Level 10

92,410 points

Sep 16, 2016 2:21 PM in response to jiokay

Glad to hear that you found the problem. 😉

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