Digital sound out of the USB C on my cell

[sophie smith]

Greetings,

I would like to find out if/how I can get the digital sound out of the USB C port om OnePlus 6. I know it has 3.5mm jack, but I would like to try external DAC.
I want to use external DAC/amp to run in-ear headphones.
I went to the developers settings. The USB audio routing is enabled. I also tried switching USB default interface to MIDI.
The DAC/amp I am using is XtremePro, thumbdrive type USB/3.5mm device. The player is foobar2000 for android
Unfortunately, I get no audio out. Is the problem my DAC, needing drivers to install? Or is it the device itself? What can I do to get the digital audio out of the USB C with external DAC/amp?
Any suggestions are appreciated.
Thanks much

 

[freemansteve]

It should 'just work' - famous last words!

I assume the DAC is an OTG USB device and also assume that you have the right adapter cable to go between the phone and the DAC included in the kit....

You probably have already turned OTG on in the Android settings, but does the DAC indicate in any way whether it is actually powered up? Sometimes OTG turns itself off after a period of inactivity.

I'm pretty sure using any setting that says "MIDI" isn't likely to be right!

 

[sophie smith]

It should 'just work' - famous last words!

I assume the DAC is an OTG USB device and also assume that you have the right adapter cable to go between the phone and the DAC included in the kit....

You probably have already turned OTG on in the Android settings, but does the DAC indicate in any way whether it is actually powered up? Sometimes OTG turns itself off after a period of inactivity.

I'm pretty sure using any setting that says "MIDI" isn't likely to be right!

Ahh!! Yes the DAC power light is on. BUT I did not realize OTG functionality needs to be manually turned on. It turns off after 10min. Found the toggle switch for it. Will try again tonight.

Just out of curiosity, is there anything specific about OTG cables/devices? Why will a regular USB C cable included with the phone not function as OTG cable? What is different about OTG devices?

Thanks!

 

[freemansteve]

No, I think I mislead you on OTG cables, it's just that some USB cables are for charging only and have no data signals in them!

 

[Jimbob54]

Ahh!! Yes the DAC power light is on. BUT I did not realize OTG functionality needs to be manually turned on. It turns off after 10min. Found the toggle switch for it. Will try again tonight.

Just out of curiosity, is there anything specific about OTG cables/devices? Why will a regular USB C cable included with the phone not function as OTG cable? What is different about OTG devices?

Thanks!

This drove me mad with the OP 3T but the 7T just connects without the OTG toggle faff. I can only assume its an Oxygen/ Android version change between the 6 and the 7 that makes you have to still do this on the 6.

To the best of my understanding OTG is a bit of a last gen thing- I think Android moved on and so recognises that if you connect a functional device like a DAC, you want to use it. Manual mounting / OTG still seems to be a thing if you want to move files/ access files on the phone from another device though.

 

[threni]

This drove me mad with the OP 3T but the 7T just connects without the OTG toggle faff. I can only assume its an Oxygen/ Android version change between the 6 and the 7 that makes you have to still do this on the 6.

To the best of my understanding OTG is a bit of a last gen thing- I think Android moved on and so recognises that if you connect a functional device like a DAC, you want to use it. Manual mounting / OTG still seems to be a thing if you want to move files/ access files on the phone from another device though.

I didn't think OTG was a thing on USB-C and was only needed on USB-A/B cables. Any USB-C cable which can physically connect two devices is ok. That's how I understand it anyway; I could be wrong.

 

[staticV3]

To use Type-A or Type-B DACs with your Android phone, an OTG adapter is required.


Type-C male DACs can be plugged directly into a Type-C phone:


Type-C female DACs can be plugged into Type-C phones with any generic USB Type-C to Type-C cable. No OTG required


To use external DACs with Android, the device must:
-support OTG
-support audio output via USB
-be able to supply as much current as the DAC needs

The OnePlus 6T at least supports OTG, Audio output via USB, and can supply about 1.7W to USB devices. The same should be true for the OnePlus 6.

 

[Jimbob54]

I didn't think OTG was a thing on USB-C and was only needed on USB-A/B cables. Any USB-C cable which can physically connect two devices is ok. That's how I understand it anyway; I could be wrong.

See Static"s post above this. But regardless the usb c oneplus 3t needs you to manually enable otg on the phone to get anything out of the USB c port but doesn't need a special otg cable to connect after that.

 

[freemansteve]

USB OTG: Everything you need to know

USB OTG is a useful feature that makes your smartphones and tablets a lot more capable. Here's what you need to know!

www.androidauthority.com

 

[threni]

USB OTG: Everything you need to know

USB OTG is a useful feature that makes your smartphones and tablets a lot more capable. Here's what you need to know!

www.androidauthority.com

That's a good example of the confusion. The author conflates an OTG cable/adapter with any USB-C adaptor. There's no mention of OTG on the product pages he links to.

Is OTG part of the USB standard, or a hack some implementations support?

 

[freemansteve]

OTG is part of the USB standard in the sense that there is a concept of "host" and "peripheral" devices, with some devices being able to be both (OTG ones), and it requires additional protocols to be supported for a device to have both the roles.

Early phones acted as peripheral devices only, in that they behaved like USB storage, to a host like a PC. And not many PC USBs can act as a peripheral (like a storage device) to an external USB "host".

AFAIK all phones for many years are all OTG.

An OTG cable is only 'special' in the sense that has different connector each end, typically different sizes, and prior to OTG, they would have been a non-functional combination. The physical USB connectors are all standard - taken on their own at least; it's the combination that makes them OTG.

 

[sophie smith]

To use Type-A or Type-B DACs with your Android phone, an OTG adapter is required.
View attachment 199708

Type-C male DACs can be plugged directly into a Type-C phone:
View attachment 199709

Type-C female DACs can be plugged into Type-C phones with any generic USB Type-C to Type-C cable. No OTG required
View attachment 199710

To use external DACs with Android, the device must:
-support OTG
-support audio output via USB
-be able to supply as much current as the DAC needs

The OnePlus 6T at least supports OTG, Audio output via USB, and can supply about 1.7W to USB devices. The same should be true for the OnePlus 6.

Well, this did not work as intended...
My set up: 12v/usb adapter for the car, outputting 2.1v. USB C connected to the USB hub Power Delivery Port, which, in turn, connects to the phone, charging it. This part works.
The hub had 3 other USB 3.0 ports, one of which is connected to the XtremePro DAC. The DAC lights up.
The headphones are connected to the 3.5mm output on the DAC. No sound at all. Tried 2 different players, MX and foobar.
The reason for the hub is to charge and play simultaneously. Not sure if this is the culprit. But no luck so far. Tried volume all the way up. DAC works fine with my stereo system at home, so that is not the issue. Not sure if XtremePro requires drivers to work? Can I get them on android?
Thanks

 

[staticV3]

You cannot get drivers for Android (and also don't need them as long as the DAC adheres to UAC spec).

The hub you're describing requires your phone to support USB power delivery to work as intended.

What phone are you using?

 

[sophie smith]

OnePlus 6. The charging part works fine.

 

[staticV3]

That phone does not support Power Delivery, and therefore does not support simultaneous charging and data transfer via USB.

Edit: here's some testing I did with one of these USB hubs

 

[sophie smith]

That phone does not support Power Delivery, and therefore does not support simultaneous charging and data transfer via USB.

Edit: here's some testing I did with one of these USB hubs

Well, that makes sense. I will try without simultaneous charging and see if I can get some sound out...
Thanks for the pointer!

 

[Jimbob54]

Well, that makes sense. I will try without simultaneous charging and see if I can get some sound out...
Thanks for the pointer!

You should get sound out then. Its not a problem unique to Oneplus but neither my 3T nor 7T would charge and send to a DAC at the same time.

The 2 pixel phones I have had could do it. Very annoying.

 

[sophie smith]

Does anyone know if the newer One+ phones, like 9/10, support simultaneous charging/playing? I guess that might be the deal breaker for me next time, esp since none of them have 3.5mm jack.

 

[staticV3]

The OnePlus 9 Pro and 10 both support USB PD according to the internet

 

[freemansteve]

You cannot use a USB hub device for OTG (at least none I've seen).
Hubs are normally 'peripherals' on the PC connection side, and a 'host' to all the attached devices - as we said above, OTG is about being able to be both peripheral and host, and use protocols to decide which is which when a device is connected.

All OTG phones provide USB 5V power to a peripheral device, but if they 'see' power from a host like a hub or PC instead, they assume the role of 'peripheral' and don't need to provide power.