Soundsignal over usb gpio

Hey Gouwa, hey Stefan,
I’ve try to connect only the usb DP/DM signal (gpio pin 3/4 or 7/8 ) from the vim to the tone board and use an dedicated PSU, but i can’t get any signal. I’m use VIM1_Nougat_V180619 and install coreelec above. All is running exelent, if the tone board is directliy on the vim/vim2.
What do I wrong ?

Thanks for help

Can you take a photo on the connections between the Tone Board and VIM1 Board?

I take a 40 pin connector ( long pins ) and cut all pins without pin 3/4 and 7/8

Thanks for help

We use USB VBUS to switch the sound card mode,so just use DP/DM is not work,the power must be connect with tone board.
please see blow picture:

Thanks for answer, but this mean’s, that there is no chance for a dedicated PSU to vim an tone board ?

If you use a dedicated PSU to vim and use the vim‘s GPIO power header to tone board,I think it’s not a good idea for tone board power supply.
If you use vim’s GPIO DM/DP and PSU for tone board with GPIO power header,you can improve the power quality theoretically.
In fact, the tone‘s power ripple control is good .

I’ve found a solution to get a dedicated PSU to the tone board and the result is to hear. Especially in the base and the spaciousness is different.

I use Thel PSU and a hifiakademie dac (over i2s ), pre / power amp.

Thanks for help !