s4 mini keeps restarting when connected to x-mini speaker

[Bram Van Zalk]

My phone GT I9195 keeps restarting when I connect it to the x-mini speaker (3,5mm jack). Does not make a difference whether the speaker is on or off. It brings up the samsung galaxy s4 mini screen and then reboots again, over and over again. The phone does not do it when I connect the earphones.
Any help would be much appreciated!