Thanks @Jesus_Rodriguez
I swapped out my ultraRendu to get a opticalRendu and I cant see a big difference (yet). Infact ultra seemed a bit clearer in my setup.
My signal path: Roon Rock -> OpticalRendu -> Matrix -> PS Audio -> …
In opticalRendu i have set native DSD as the format.
All 3 switches (Dop, IIS reverse, MCLK) on matrix is set to OFF.
Did you ever try take out the Matrix and contect the OpticalRendu to PS Audio through USB port. What I think is Matrix will do some signal treatment and it will effect the true taste of Rendu.