Glyn Barnes
I would have assumed you would need a decent audio interface??? Something like a Roland Duo capture or this new bit of kit from Focusrite. Or can you really get decent sound with low latency out the headphone jack?
Yup, the iPad headphone out could go straight to a DI > FOH, in a performance scenario.
Edit: I've been testing it the last few days with the iRig KEYS controller. It's pretty fantastic and I'm not an Apple, Synth, or keyboard guy.