Orange amp 35ldx, Line out sounds Bad?

i just bought a orange amp 35ldx, and the amp sounds great when i play it normaly, i got it as a replacement for the cube 60 my brother blew out. when i plug the line out into my audio box and rout the sound into cubase, the tone sounds really bad, like very tin sounding, and when i use headphones on the amp it sounds the same........... is this normal for the line out to sound different then when you play it normaly, or is the amp broken? thanks for answers