subwoofer makes all speakers hum
I just got a denon x4400h because my sony za1000es is not meant for the 4 ohm speakers that I have.
Now, whenever I plug my subwoofer into the denon, (to either subwoofer 1 or 2), it makes all the speakers hum. This does not happen when
I duplicate the setup with the Sony.
The receiver I got was a refurbished one, and when I first got it, the menu wouldn't come
up, and the screen looked like the picture below. Then it just randomly started working, after power cycling it 4 or 5 times.
Is it possible this is from a faulty receiver?
And more importantly, could that humming cause damage to my speakers?
it's not that loud, but wondering if whatever is causing the interference could cause internal issues in the speaker components.