Apple Cube Speakers fixed

Are your good old speakers you had with your Cube suddenly not working any more after an upgrade of Mac OS X? Chances are that you can get your music back.

Is there a message in your console log:

kernel: Couldn't alloc class "AppleUSBTrinityAudioDevice"

Do headphones still work?

Then the answer is: yes.


The little box with the USB cable that comes with the speakers contains two chips. A Micronas 3552 USB/DSP chip that handles USB data, converts the digital data stream to audio, and drives the headphones. It has a built-in amp for that. So, if your headphones still work that means that basically your setup still works. You can find a uac3552A data-sheet here.

The second chip is a digital amplifier. It's a TA1101B "T-amp", a true digital amplifier device.

What is wrong after a certain Mac OS X version is that the driver software does NOT switch "on" this T-amp ("T" for "Trinity") amplifier any more.


There are two solutions. A temporary software one, and a permanent hardware one.

Software "fix"

The software fix is to try an older version of the "AppleUSBAudio.kext" extension, that lives in "/system/Library/Extensions" and loading it with the commands "sudo kextload /System/Library/Extensions/AppleUSBAudio.kext/" and/or "sudo kextunload /System/Library/Extensions/AppleUSBAudio.kext/" in various combinations. That worked for me until Lion.

Hardware fix

The T-amp needs switching on. The TA1101B, according to the TA1101B data-sheet, has two pins that need to be "0" for the device to be switched on, and non-muted.

Pin 11 is named "MUTE". When logic "high" the device is muted, and the internal amplifiers idle.
Pin 16 is named "SLEEP". When "high" the device sleeps. (Luckily it does not snore.)

Grounding these pins permanently switches on the T-amp. Below is how to achieve that.

Rick Jansen,