Prodigy cube upgrade

Hello all. 

I am presently using a Prodigy Cube as a converter only for my Audio Note 3.1 DAC.  I have a second system but with a Audio Note DAC 1 Signature that I would like to try something different with. Can anyone make a suggestion for an upgrade to this converter. I'm quite happy with it and they're very reasonably priced at around a hundred bucks. I don't mind paying more if it will make a difference. 

 Thanks for your suggestions.