Here's what Hughes & Kettner say about the WMI-1 MIDI Interface
The Hughes & Kettner WMI-1 enables you to wirelessly remote control all of the functions found in the GrandMeister app for iPad. Even on stages or in rehearsal rooms where Wi-Fi is not available, the WMI-1 creates its own Wi-Fi network!
The WMI-1 features two MIDI inputs and one MIDI output. It is easily connected in-between the GrandMeister and the FSM 432 MK III footswitch, and the GrandMeister even provides the WMI-1 with phantom power.
To use the WMI-1, all you need to do is to select the WMI-1 as a Wi-Fi network in the Wi-Fi settings of your iPad, or connect it to your home network using the WPS function.
Although we have optimized the WMI-1 for use with the GrandMeister and the matching app for iPad, it also works with any Hughes & Kettner amp featuring a 7-pin MIDI input (phantom powered) and any app for iPad that supports CoreMIDI.