Hi, yesterday i got the ax8, it works fine until i want to use (USA model amps) if I use them there isn't output signal, even if i change to another amp that previusly worked the output signal would still be 0. To use the ax8 again i have to switch it off and turn it on . I noticed also that when I use any USA model this is what i can see in the screen. If any could help me... 