Will I see a big difference from my ifi zen blue to a denafrips ares 2

Depends on your definition.

Please explain  thanks 

I do not know about seeing but you may hear a difference cause one is chip DAC and other is R-2R. Two totally different topologies, you may prefer how one sounds in your system over the other. If you're serious about upgrading, consider Pontus II, as I hear Pontus holds the sweet spot in Denafrips lineup. 

@byner 

Yes of course you will hear a difference, but you might want to refine your question to include what other equipment you have in your system and what you are looking to hear.