Many thanks to all for the precious answers.
So , if i understand correct I have to predilige a "balaced" solution connecting hd500 live-out (with an adapter obviously) to monitor line input or hd500 xlr to monitor mic input.
Another question (sorry for that and for my poor english :)) i read from another post that the xlr signal is lower than unbalanced signal. Is this noticeable or it make difference only for few decibels?
Using only a single xlr, NOT using stereo effects and panning in the mixer all in center, I think that I shouldn't loose anything regarding the patch sound. Is this correct?
Thanks to all again.