I'm playing a show but the sound man is a bit of a novice and doesn't know how to hook up my guitar amp to the sound board via DI. I've got a Fender Deluxe 90 amp. It's got two 1/4 inch slots on the back: PWR AMP IN and PRE AMP OUT. The DI box has two 1/4 inch TRS-style inputs ('from instrument' and 'to amp'), one XLR input (this one obviously goes into the console), a ground switch and switch with three gain settings (two negatives of I forget how much and one unity). We tried hooking it up via the PWR AMP IN slot (i.e. Guitar->from instrument DI, to amp DI->PWR AMP IN) but that didn't work (I got my usual amp sound but nothing came through the console). Actually, I'm not even sure if my amp has a slot for DI output.

How to fix.

what you want to do is take the pre-out to the DI's TRS in. XLR out to the board. and TRS Out to PWR AMP in if you want your speaker to still work. of course. guitar in INPUT.