So, If I've well understood, it is not possible to record my guitar on the way with my iPhone/iPad if I have no headphone or amplifier to connect to the Sonic Port VX... So, the use as nomad device is a little bit limited... :(
But, in case you use the microphone and you record with Apple App "Dictaphone" (I don't know the English name of this app), it is possible to hear the result without disconnecting the Sonix Port VX on the speaker of the iPhone/iPad. So, in this case, IOS replaces only the mic, but not the speaker.
Do you have an explanation ?