Hello, I have noticed that when I use the electro-harmonix voice box, the loudspeakers crackle a bit, but I do not have the way activated high but low. It seems that the sign increases only for the equipment connects voice box to the mixing desk…
The cables xlr are balanced and the jack of guitar is not, as they say the instructions.

Can it be a breakdown? The voice box is new and works very well except for this small noise in the loudspeakers…

Thank you all!