I have permanent prioblems connecting my H9 to an iPhone 5S and an iPhone 6S, but have so far not had any problems connectiong it to my iPad Pro, my iPad 2 Air, and my old iPad 2.
Do you have iOS 9.3.1 installed on your iPhones? As noted in this forum post, there was a bug in iOS 9.3.1 that caused Bluetooth connectivity problems in certain iOS devices.
Having now tried multiple times with three different iPads and two different iPhones, I am a bit concerned that Eventide staff is seeking to find all sorts of reasons beyond own software/hardware. As the H9 app is available for both iPhone and iPad, I would suggest that Eventide perhaps have a closer look to see if the problem might not be in their app and non in different power supplies and other reasons?Show More...
We're more than happy to look at your H9 if you want to send it in to us. We hate having people send things in though and then have to tell them that we couldn't reproduce the problem and so there's nothing we can do to help.
When there is a problem with an H9, normally we'll see it behaving in one or more easily recognizable ways that we've seen before, and we'll ask people to send it in to us or return it. If it's not a problem that fits a pattern we recognize, we have to ask people to do a bit more work to help narrow things down.