condenado

Finally I have understand what is happening :D . The fx send jack is line level, so it can't go well with an instrument input like my amp input. The only solution is a reamp box to conect "fx send" to "amp input". Line 6 have put a line/instrument selector in the hd500 for this, but in x3 live it ins't possible to change this. here you can read about it: http://de.line6.com/supportarchive/thread/53173

I have put off 3 cables, with the x3 live playing I have conect a cable (new and good quality) from send to amp input, the noise is there with the loop on, and goes with the loop off.

yes, I have the noise gate on. Settting are ok. It must be a ground issue.

I have used new cables but the hum and white noise are still there. I have flashed the x3 live and still there. If I conect my guitar in the x3 input and from send to amp input with the pod loop on the noise is there. Are there any posible solution?

Thanks, I have to buy a set of new cables and give another try. But I'm thinking my x3 live could be defective. Do you think I would have to reinstall the flash memory?

The noise that the x3 live loop adds to the signal makes the 4 cables method unusable, a pity.