Hello, It plays music thru the internal speakers, but when I plug in my external cable into the audio jack there is no 'switch' to the external output and so the internal speakers continue to play. I ran Hardware test and it says no problem. Everything was working fine since i bought the unit earlier this year, and I'm thinking it may be related to a 'electronic signal overload event' that happened just last night: our buildings' front door buzzer got stuck on, and when I walked into my apartment last night my powered monitors were playing static even though there was no signal going thru my digital preamp. I live in a very old building with wiring that obviously has a lot to be desired. Could be related or not, but time-wise it's a 100% correlation. When I hook up the preamp directly to my ipod it works just fine thru the powered speakers. Any suggestions as to where to start to trouble shoot, short of taking this beast in?