Start with a DAC that you like.
I have a pair of martin logan 40i. Blusound node most recent version. Anthem mrx 720. I have the speakers connected with bi wire blue jeans speaker cable. The blu sound via optical cable. I have about 1000 dollars. What could I upgrade. Thought about getting an amp like the parasound 23+ or upgrading the streamer to a cambridge. Please I would love some help/suggestions.