I use an ultraRendu with a S booster.
Would love to know your experiences re Sound Quality, on whether worth replacing completely with an opticalRendu or if there are worthwhile improvements just using a single optical module with existing ultraRendu.
I first tried an opticalModule with my ultraRendu and liked the new sound quality. The problem was that this solution couldn’t handle HQPlayer without dropouts, So I bought the opticalRendu which I feed optical from an etherRegen. Now my system sounds very good. I don’t use my opticalModul because of recommendations to go directly from etherRegen to the opticalRendu.
In my opinion the opticalRendu is better than the ultraRendu.