Ways to improve DAC performance???

Hello fellow A'goners,

I recently changed my system by selling my tube CD player and storing all of my CDs onto iTunes on my Macbook Pro laptop. I also subscribe to premium Spotify and really enjoy the quality of the sound.

I'm using a fairly inexpensive Ross Martin DAC, and the noise floor and detail are really excellent.

I'm new to this "music server" approach and I was wondering if there is additional software that would improve the quality of this setup.
It has to be Apple, not PC.

I've read of various programs and downloads that help, but I'm not sure if they are a substitute for a good DAC or something that can enhance a DAC's performance?

Any suggestions or advice is much appreciated, as I am a newbie in this new digital realm.

Thanks! Lincoln