It depends on the specific product model.
On some Sailfish-based products, DSD audio is not converted to PCM, which means the EQ function does not apply when playing DSD files. This is a design limitation rather than a bug, as EQ adjustments can only be applied to PCM streams.
EQ does not work with DSD playback on the following products:
Evo 75
Evo 150/150DE/150SE
AXN10
MXN10
CXN100
EXN100
EQ does work with DSD playback on the following products:
Evo One
L/R M
L/R X