1997 CDR-210 dash speaker power loss
 

Hello all,
I just replaced the dash speakers in my 1997 Boxster with Alpines and all was well for about an hour. They went out (door speakers work, though) but came back on after I turned the radio off/on. A few minutes later, they went out completely.
I pulled the radio and all connectors are tight, speaker wires are good, fuses good but no change...just the muffled subs working. I DID find a disconnected blue/brown wire with a connector on the end inside the radio housing, but see no where it would plug.
Could it be radio head? Amp in the trunk? I hear differing opinions of which powers the dass speakers. Any ideas?
Thank you!