Hyperpixel 4.0 sound?

Is there any way to get sound output from the I2c connector on the back of the Hyperpixel screen? The screen uses all the gpio pins and if I solder directly to the 3.5mm jack pads on the back of the Pi, I still get sound output from the external speaker I have connected when I plug in headphones.

Thanks

I think you’ll find that most digital sound boards (DAC) that connect via GPIO use i2s not i2c. And i2s is disabled with the Hyperpixel as it repurposes those pins for other functions.
Why did you solder to the jack pads?
I used one of these to avoid having to solder directly, https://www.adafruit.com/product/1700
You’d have to unplug it to use headphones though.

I still want to have access to the 3.5mm jack for headphones. I’m using this in a custom handheld gaming device, and the external speaker is wired to this, which is wired to the audio pins on the jack.

I’m pretty well using the stereo version of that with my pigtail

The audio jack on the Pi doesn’t work the way it does on a PC. As far as I know its not going to auto detect that you plugged something in and toggle from HDMI to analog automatically. And even if it did, by soldering your amp onto the test pads your hooking things up in parallel. You’ll have to wire up a switch to disconnect your amplifier when you want to use head phones. Or do what I did, use the pigtail. Then you just unplug the amp and plug in your headphones. And plug the amplifier in again when you want to switch back to speaker.
Another option is to try and find a breadboard friendly tip ring sleeve jack with the cutout function and wire that in between your speaker amp and Pi, and plug your headphones into that jack.

And wire it up on something like this

I’ll look into doing the secondary headphone jack. Thank you for you responses.

With a little work you should be able to get it working the way you want.
Another option is to put a switch in to turn the power off to your speaker amp.
Or put the switch on the audio going to the speaker amp to disconnect it when you want to use headphones.

I dont have any specific links to offer at the moment but audio jacks that physically break another connection when something is plugged in do exist.

The breadboard friendly jack I posted above has the disconnects. It would normally go between the low level analog audio out and the speaker amp input. Plug headphones in and the speaker amp is disconnected.
This isn’t going to work if your signal into the speaker amp is digital i2s etc though. That signal can’t drive analog earbuds. If your picking the audio off of the Pi’s similar analog audio out jack it will work though.