Presumably the B&O speakers are active, and are wired via the Port’s RCA outputs. Do they perhaps go into standby after 2 minutes?
It sounds like a grounding issue. It might help to connect an available sheath, on one of the spare jacks, to the electrical earth.
Yes they are active and i never had a problem with the previsously wired CONNECT, it worked perfectly.
Only when i stop playing music, almost exactly 2 min later, the humming begins.
It is as if the signal from the PORT stops after 2 min and the humming begins. If i start to play music again, then the humming stops, and then the music begins? So i don't think it is a grounding issue?
Thanks
I noticed something similar with a Port connected to a headphone amp. There was a tiny amount of background hum until the amp was powered on. Neither the Port nor the amp were tied to the electrical earth.
Grounding the assembly -- by earthing the sheath on one of the unused RCA jacks -- caused the hum to go away.
It’s not hard to test, simply by touching a grounded wire onto a suitable spot.