I tried it on my old iPad 2, interesting, no pops or clicks for me then. Im using Sonic Port and the Mobile Pod app. But Ive tried a variety of guitars, cables, and headphone combos with the Sonic Port on my iPhone 6s and Mobile Pod app, as well as Garage Band and it definitely had some issue going on with random popping sounds.
Too bad but I feel I may return the Sonic Port and try one of the options which plugs into the headphone jack vice the lightning port. I use this mostly for in hotel rooms while on the road for work, dont want to listen to those random pops. Its really a shame because I absolutely fell in love with the variety of tones in the Mobile Pod app.
Hopefully someone has some advice on this.