[sktn77a]

I am having a problem with my 2001 BMW E39 audio system upgrade. The system is a standard US (non-DSP) system with the OEM BMW "Business Cassette" head unit (made by Phillips) and a 6 CD changer. I added two 10" DVC subwoofers (the OEM BMW M5 subs) and a Blaupunkt PA275 amp to drive them. Low level inputs to the sub amp were taken from the head unit outputs just before they enter the BMW amp (standard coax signal+ and ground- cables and plugs into the sub amp). Despite what I'd read about these head unit outputs being balanced, the system has worked fine for 8 years!

Now I have just replaced the OEM Phillips Business Cassette with an OEM Alpine BMW Business CD. Same connectors, designed to work with the same OEM amp, but I've lost the sub audio output!. If I plug an MP3 player into the sub amp at the RCA inputs, I get bass but nada from the line level inputs from the new OEM CD head unit. I am switching the head unit out for another one just to make sure it's not a bad head unit. However, I'm wondering if the balanced outputs from the Phillips cassette head unit could be somehow different from the Alpine CD head unit? The the new CD player drived the 10 stock speaker just fine (?)

HELP!!!!

Thanks

Keith