As an experiment I played with variable volume and EQ when I first got my WiiM Pro last year (connected via coaxial digital to an Onkyo TX-SR805 AVR) and all sample rates remained unchanged according to the receiver's front panel display, which shows the incoming sample rate but not bit-depth. Normally I leave it at a fixed volume with no EQ but I just wanted to see if doing so would force it to a fixed sample rate and it does not.