I hear the hiss when I change the speakers from Athens ASB2 to Polk R30 and back. I can hear it only when I am very close to the speakers. I cannot hear it from the normal listening distance. Is this nornal? If not is this a problem with speakers or the receiver. My receiver is a Yamaha 5730s. All equipment are brand new. I followed an audio salesman suggestion and upgraded my speaker wire to Monster 16g wire but the hiss is still there. please help.