Mobile audio: Charge phone and use USB DAC/amp at the same time?
Jul 30, 2022 at 3:04 PM Thread Starter Post #1 of 6


1000+ Head-Fier
Jan 23, 2014
Wisconsin, USA
In the car, I'd love to use a USB dongle from my phone into the aux input on my head unit. Problem is, of course, they can eat through phone batteries pretty quickly.

Meanwhile, I've noticed that products like this exist:

The USB-C port is for charging and the USB-A port is for USB devices. But has anyone here used this with audio dongles before? I use the USB Audio Player Pro app. Will a USB-C splitter like this prevent UAPP from using the audio dongle, or will it be fine? Has anyone tried this before?

Jul 30, 2022 at 4:09 PM Post #2 of 6
Side question, what's your car stereo setup out of curiosity? HU, speakers, amps, subs, etc.
Jul 30, 2022 at 6:45 PM Post #3 of 6
Side question, what's your car stereo setup out of curiosity? HU, speakers, amps, subs, etc.
Nothing particularly interesting. Alpine 143BT head unit in an otherwise stock Honda Element. I got the head unit in the hopes that the Bluetooth would be useful for music from my phone, but it's really really isn't. And other Bluetooth methods (BTR5, Qudelix) haven't proved to be as reliable as I'd like, so I'm hunting for wired methods.
Jul 30, 2022 at 6:56 PM Post #4 of 6
Oh I see. The reason I asked was because certain head units have (or had) USB inputs on the back, that would both charge and work as audio inputs. Yours does not, unfortunately.

I think for the price of that cable, buy and try.
Sep 5, 2022 at 6:23 PM Post #6 of 6
Here's an update for any future Googler:

I found success with this connector,

Audio dongle goes in the USB-A slot, power goes in the USB-C slot. Phone charges while playing music out of the dongle no prob. I use this in the car to get good audio out of my phone to the aux input in my car, while simultaneously charging the phone. Great for long trips.

I think the trick is to find connectors specifically described as "OTG adapters" versus just simply "USB-C splitters." I think the "OTG" USB protocol is official and somehow different to enable this kind of functionality over simple USB-C splitters. Also, you want to make sure that your OTG adapter is capable of fast charging and that your charger is also a fast charger, so that you are charging the battery faster than your dongle is depleting it. The one I linked above ticks both these boxes.

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