I don't have enough $ to recommend a nice DAC but I hear lots of talk about Laiv, Holo Audio and others, tubes or no tubes. for example. Sure, the signal comes from a cheap box somewhere but once you get the sinal in your house you need good solid connections and I use contact enhancer. Sometimes the connections can oxidized otherwise. Noise filters and a power conditioner helped as well. I am assuming you have updated power cords. I also isolated each piece. You can spend as much as you want on filters, etc. A separate DAC is not a waste either.