Okay, so somebody help me out...if you use a powered midi controller, you don't need to power the USB hub right? When I plugged my keyrig to the camera connection kit, it said there wasn't enough power to use the accessory. But when I used the USB Midi out from the church's Yamaha MoX, it didn't work. Am I doing something wrong? I figured since the yamaha is already powered it should be able to power the USB connection. Help please lol.....
Here's how it works. The MIDI keyboard not only need to be MIDI class compliant, but if it is USB powered the power requirements cannot be too high. In other words, the USB controller cannot require too much power, otherwise, it won't work. In fact, I have a Novation Remote SL 37 that can be battery powered, however, even when it is battery powered the iPad is complaining about it not being able to supply enough power.
Hope that helps. Also, IOSMIDI.com is an awesome resource for what is compatible with the iPad.
BTW, when you say your church's, "Yamaha MoX", do you mean "Yamaha Mo8" being that the MoX has been released, yet?