OK...
Got the Yamaha MD-BT01 yesterday, and was fairly successful last night with the info that both reneguitar and mollydyer supplied above!
Thanks guys!
It took me 15 or 20 minutes of fumbling around before I realized that you don't pair the device to your phone/tablet, you pair it to the app you're going to use (Bandhelper in this case). Maybe that's different in iOS, but in Android that's what I had to do. Plug the device into the Kemper, open the app, open the Midi status page, and choose "Connect to a Bluetooth Device". Finds it in seconds and you're done!
It is powered by the Midi out port, so no batteries.
I am impressed with the distance my tablet can be from the device/Kemper. Currently the Kemper is in my living room, and I can switch performances etc from in my Kitchen, a good 25' away! Should be no problem at practice or a gig.
Now I have a question...
If I use the Control change method #48 - 1, the Kemper jumps to Performance 1 no problem. But it sits there waiting for you to stomp one of the 5 rig buttons before it will activate that rig. I can see that being good for some people, but I want it to naturally load rig 1.
I went to System settings, and Perf.load, and changed that to 1 instead of "pending" and it won't load slot 1. Neither does "Keep slot" work. Only the default "pending" works, which again forces you to stomp on a slot.
Any ideas why? Think it's a bug?
Using the Program change method, you get the slot you want every time.
Hmmm...