G4 Cube Speakers Modification

[broots]

Hi All,

I recently modified my G4 Cube speakers to run from any computer over USB and also added an AUX input. The speakers have a decent sound and great style but the limitation to running them only with a Cube was getting me down. I have seen other posts about folks enabling the G4 Cube speakers via software but a post over at sudoroom pointed out that two of the onboard ICs can be hardware modified to enable USB input from any computer and add an AUX input.

The first step was to crack open the speaker amp enclosure which is glued together. Mine came apart with a little prying.

The first and easiest modification I did was to disable mute to allow the speakers to run from any computer over USB. From what I had read the one special thing being done by the G4 Cube speaker driver was to disable the mute function of the TA1101B IC. This is necessary because the TA1101B pin 11 is wired HIGH by default to enable mute. To disable mute with hardware involved lifting the 5th pin from the bottom (PIN 11 in the data sheet) of the TA1101B from the board and running a wire from the mute pin to ground.

After this step I plugged the G4 Cube speakers into my MacBook Pro and they appeared as USB speakers. Ta da!

Getting the AUX input to work was a bit more involved and required a few more components to replicate the circuit diagram from the UAC3552A data sheet:

I can provide more details for anyone interested, but the speakers presently power up from any USB source, have two inputs, and can playback simultaneously from USB and AUX. Am now using them with two Macs simultaneously

 

[CooperBox]

Neat mod, and excellent photos. Bravo!

 

[weckart]

What is the power draw from your notebooks? As far as I can remember, the Cube speakers are wired to send a signal to the Cube to allow for a larger than normal power signal from the USB port otherwise you are not going to get much change out of them.

 

[broots]

@weckart The power draw defaults to 500mA or 2.5 watts over USB. Yes, it is slightly louder when powered over one of the Cube's USB ports with the originally intended driver to enable the full 10 watts / 2A. I am surprised by just how loud they are on the lower wattage though. From what I can find about the relation for speakers between wattage and volume - to double the volume would require 10x the wattage. Yikes! So while the difference from 2.5 watts to 10 watts is perceptible 2.5 watts is still more than half the potential volume.

 

[weckart]

I did wonder as I have a Griffin iFire, which uses Firewire (12v at 1A) to power the Apple Pro speakers rather than USB. If you put your hacked speakers on a modern Mac with USB 3.0 you will potentially get 5v at 0.9A minimum, if following the USB 3.0 standard, so the drop off in volume will be less perceptible. On a PPC Mac, where you never seemed to get the 0.5A of USB 1.0 or 2.0, thanks to stingy Apple, I would think the speakers would be a bit quieter but it depends how loud you need them to be.

 

[Project Alice]

They already work on any computer the problem is power draw. They work natively in Windows. On El Capitan and higher they require a patch because Apple blocked them but they still work fine.
I’ve been using them on my Mac Pro for over a year.