Originally Posted by heavyduty
To begin with, the humming noise may be due to the ground. Check to make sure this connection is tight and secure. Also, are you using High Level or Low Level Inputs for your signal source?
The switch you are referring to is called the phase input switch. If everything is working perfectly, there is no need to change this position.
If you disconnected the power to the headunit at the start of the install (which is something you should do in all installs) the unit will reset itself due to the loss of power. To turn these settings back on check your owner's manual to see if you are skipping a step. Normally, installing a Tube will not cause features of a headunit to stop working.
Don't know if its high or low level inputs... I simply ran the wire harness that came with it to the back of my headunit, it T's right into the main input plug... unplug the factory one, plug in to the bazooka harness, then plug the bazooka harness into the headunit, then plug in the blue remote wire hookup to the blue "Remote 2" plug, and it works...
I will try finding a different/better ground and see if this helps get rid of the weird noise at startup and shutdown.