Matrix X-SPDIF 3

[Wei Cao]

For your information: i had a Topping U90 DDC here, no problem playing with that one. The only problem with Topping U90 was that it could not play 768 kHZ, and it was not better than playing with usb direct to Topping D90SE.
Tore

Sure, Topping's DDC should work with their DAC without any problems.
There is no standard of the IIS connection in the industry, every manufacturers may define the pinouts according to their requirement.
As you mentioned, the DAC is getting data from Matrix X-SPDIF3, the reason why there is no sound is, Topping requires a high level signal or disconnect the pin to indicate Unmute command, but Matrix is using a low level to indicate unmute.