I am using Sonos App from my PC and sending music to Sonos: Connect. The "Connect" is hooked up to a Onkyo P-306RS Super Servo Pre-Amp powered by a Onkyo M-506RS Power Amp. The connection works fine, however, when I'm not playing music (no volume) I can hear "popping and cracking" (static) from my speakers. Sonos folks cannot identify or provide reasons for the crackling sounds. Please, anyone experiencing like issues provide remedial action.