Ok so this is a follow up to my previous post whereby i bought the Astro Mixamp 2011 version:
The mixamp arrived today ahead of schedule. Almost like 2 weeks early to Sydney, Australia
I tested it and it's brilliant. I could not hear any hiss from the volume levels i checked. I didn't go too high as i didn't want to damage my hearing
I would say i went to around 60% volume by turning the volume knob towards 2pm. However i will test higher volumes later on.
Also i compared this to my Turtle Beach DSS and seriously couldn't tell a difference in game audio. They sound the same to me. However i bought this for the chat feature which the original DSS lacks.
I plugged a modmic 4.0 into the mixamp with an adapter and people heard me fine without any distortion or muffled voice. I could hear people fine as well.
All in all well worth the money. I don't know how the 2013 Mixamps and onwards work as i have never tested it but this one is pretty good as well.
Also a nice feature the 2011 mixamp has is the ability to connect multiple devices to it since it as optical, coaxial and standard RCA inputs.
I have posted a photo below showing the 2011 mixamp and if your interested you can purchase it from ebay: