SPDIF converter for Audio Note Dac 2.1

I have an Audio Note Dac with old digital connection that I want to connect to my Macbook Pro. I have been doing this with a M2Tech Hiface but 1) the sound isn't great - positively am radio like and 2) itunes through Pure Music and a much inferior dacmagic sounds better. Is there a spdif to usb converter that is going to rival my pure music sound or even better let me use pure music into my audio note dac? This computer audio stuff can be complicated for us old guys!