I read a while ago about USB-C audio cable in this thread and about pinout. That is the only place I could find where Bluedio and pinout were mentioned...
As I could not find any more info about it and I refuse to pay Bluedio $15 or so for the cable, I thought I'll make it myself.
To prepare, I ordered USB-C female breakout board to find out the pinout.
https://www.aliexpress.com/item/32959500776.html
So here we go:
Tip is connected to A8 SBU1/B8 SBU2 (depending on which way you insert it, only A or B set is connected at once)
Middle ring is connected to A5 CC1/B5 CC2
Large ring is connected to A12 GND/B12 GND
There might be some resistors on some pins but I have not detected them yet. There are lot of pin combinations to go through.
I tested A5+A12 using breakout board+PD cable and I got right speaker working.
But I do not have any cables at the moment that have A8/B8 connected...
All A pins are on one side of USB-C connector and B pins on the other. There are total of 24 pins.
The bad news is that is uses pins that are not usually present/connected on cheap cables/connectors (USB 2.0).
USB-C has so many contacts which makes them super small and super difficult to solder. 5 on microUSB vs 24 on USB-C.
It might be pretty difficult to DIY the cable.
SBU1/SBU1 are Secondary Bus pins - used for sideband data when in DisplayPort mode - maybe for something else too.
CC1/CC2 are Power Delivery communication - used on PD chargers for voltage negotiation and such.
Only GND pins are common and should be present on all cables/connectors.
Instead of buying USB-C jack and trying to solder to super tiny legs (or buying HUGE breakout board which will not work well at all), it might be better idea to find cable that has all required pins connected, chop off one end and replace it with 3.5mm jack.
To do that, you probably will need USB-C breakout board to detect right leads. Something like this:
https://www.aliexpress.com/item/32959500776.html
Finding suitable cable (cheaply) might not be easy. It needs PD communication pins like on PD charger cables, but those might just have CC1/CC2 and VBUS/GND. Cheap USB-C (non PD) cables are just USB 2.0 and probably just have D+/D- VBUS/GND.
So what's left? Quite expensive (for usb cable) USB 3.1 cables for connecting docking station to computer or for powered display. Those might have all the pins connected.
How can you know before buying? You can't!
So can you DIY bluedio cable? Yes.
Will it be easy/cheap? Probably not. Depends on your skills and/or luck.
I will receive some USB-C jacks soon and I'll see if I can make it work. But I am not very confident...
If not, I will try my luck at buying some USB-C cables to experiment. I can buy a few for the price of one Bluedio cable.
About Bluedio headphones...
I am disappointed that they removed 3.5mm from headphones. This USB-C is stupid.
I would not mind USB-C if I could use regular cheap USB-C to USB-C cable and connect my phone/computer to headphones (some sort of integrated USB audio device or something like that). But I can't.
I would not mind it if I could pick up extra cable for €2/$2 or so on AliExpress, but I can not.
I am also very disappointed that they removed all the buttons.
I can not live without volume buttons. And changing track is also nice - no need to grab a phone or unlock computer for that.
And ANC has been a problem on every model I have tried.
You should not be able to turn on ANC when phones are off. But you can (just no ANC effect). Or you forget to turn it off when you turn off your phones. And then it drains your battery. Next time you pick up your headphones your battery will be flat. And you can not use cable because it costs almost as much as headphones and it was not included (at least with T6 it was not).
And I am dissapointed that there are 3 modes which sound all very different but they should sound very similar:
1. Bluetooth + ANC on - really cuts bass and changes audio to worse.
2. Bluetooth mode - seems to have bit too much bass for my taste.
3. Cable - best sound you can get out of them (if you even have a cable).
I have T4S and T6 at the moment. I have sold the rest.
They both have potential and both could be better products... but they are not. And T6 is actually mostly downgrade compared to T4S because of missing buttons.
That is not something new. It has all been said before many times.