can i use 2 out put together in the same time?

if it can. how about the quanlity of sound,it drop or not?

Trends PA-10 provides ONE output only. You need to DIY the cables if you want to have two outputs. We do not suggest to have any change. However, we would release a Trends PA-10x for giving two inputs in coming days. You can set up bi-amp audiio systems (i.e. One Trends PA-10x + Two Trends TA-10.2P power amp).

do pa-10 preamp/headphone have 2 outputs?

Trends PA-10 has ONE output only.