Hum before and after install the Anthem system

[peter ds]

I have installed a Anthem in one of my guitars, when I plugged in I hear a hum against the sound . The sound of the pu is good.
I have tried a new one and it has the same problem.
The hum is also hearing when the system is out of the guitar.
When I hold the output (cable) the hum is gone.

Please have somebody an idea what the problem is?
Thanks

[Caleb_Elling]

Hi Peter,
Have you tried using different cables yet? Sometimes a bad cable shield can cause noise like that.