+1 @dayglow
Upgrade your amp then source and have basic room treatment.
I would modify this advice just a little bit. Often, the room is a big and overlooked factor affecting the sound. With that in mind, I would do things this way:
(a) Test your room and see if there are large bass and reflection problems. Play with positioning to mitigate problems. There are a lot of resources out there about this and basic room triage can be done quickly. You will then have a better baseline to judge every other component.
(b) Consider getting a better DAC than the Sprout. An R2R topology might be just the ticket.
(c) If (a) and (b) don't help improve things a lot, then a better amp might be the ingredient that tips things significantly forward.