Good day! I have for a long time gone without a proper DAC. I have been using my Asus Zonar DG attached to my Matrix M-Stage AMP 2012 v2.1 with my Ultrasone HFI 780's.

I want to purchase a DAC so that I may reap the benefits of my AMP and headphones. My first question is, will I even notice a difference with my hardware? and Secondly, is there a USB DAC under $200 that would noticeably improve the sound quality of my content?

Thanks for all of your help guys.

Whether you will hear an improvement depends on your system. I didn't hear a difference between my Alienware M11x R2 laptop and a $99 Schiit Modi 2 DAC. You'll be much better off upgrading your headphones, then getting a DAC later, even if a DAC does improve the sound of your system.