Hi there, I am planning to get a Senheiser HD 800 and Audioengine a5+ speakers. I already have a Asus Zonar Stx in my pc. Do I need to get another dac and amp or is it recommended? If so which one should I get. I am looking at Desktop Objective2/ODAC with RCA? This is a good choice if needed, since it has a speaker and headphones out ports. Should I get a cheaper version of this or is this model suited for my needs?