I just got a new 6400 and a Maestro and found an unusual problem with the Maestro. I hear a low level squeal just below the receive audio that does not vary with volume. This occurs with either headphones, internal speaker or external speaker. If I connect the headphones or speaker to the 6400 I don't hear it. The PC, Maestro and 6400 are all connected to a gigabit router. The PC I'm using is a Dell desktop with a I5 processor running Windows 10. In trying to resolve this I found that if I connect the Maestro via Wi-fi it goes away. I would prefer to use the wired connection. Has anyone else experienced anything like this? I will experiment with location on the switch and cable routing but not sure what else to try.