Actually the sound from the DSS is much clearer than the Mixamp due to no interference from the mic channel.
Tried the DSS once with the DT770 80ohms but it doesnt work out so well but for the AD700 its more than enough.
Followed your giude and bought the AD700 + Turtle Beach DSS2 with Bassboost. The sound coming out of this combo is just bloody insane.
The DSS2 really help the AD700 to fill in a lot of weight to the sound.
Have a pair SM3 in great shape and would love to trade for a pair FX700. I´ve been having balanced amateurs IEM like forever and would like to make a switch to the other side for a change
Send me a PM if youre interested
I have the Sony X, Clip, Iphone 4, Ipad 2 and the best sounding is the X followed by the Iphone 4, Clip, Ipad 2 when paired with the SM3. And about those RMMA graphs i dont think they reflect much of real world performance just my 2 cents