Asus Maximus VI Gene C2

Hi I´d like to buy a new Gaming Headset and I´d like to buy the Astro Gaming A40, but i do not like to buy the MixAmp Can I use the 7.1 Surround with the A40 with my PC without the MixAmp? I also dont want to buy a new soundcard, cause there is already a soundcard at my motherboard Asus...