My son has one I shall ask him tomorrow when we Skype (he in France) but I would assume you just select inputs 3/4 and not 1/2?
BTW he has discovered that you can get about 4hrs recording from one of those el-cheapo 2200mA USB charging batteries. He does this when recording the trio he plays bass in. The recorder goes through AAs like Tasscam have shares in Duracell!
Dave.