For my first gig last Sunday, I was told it would be helpful if I brought an amp that had an output jack that could be plugged into the sound board.
I've never given this a thought, so I checked my three amps. Both of my Fenders do not have an output jack, but my Monoprice (see this post for more on the amp) has an 8-16 ohm impedance speaker output. So I took that. The sound guys had some issues with getting it to work (it was actually too hot), so they wound up mic'ing it.
My Line6 AMPLIFi 30 has a headphone out jack (1/4" not the 3.5mm). Would that work as an out to a sound board?