In the base system the Head Unit uses analog outputs to the speakers.
the fiberoptics are only used for connecting bluetooth and accessory modules
and have nothing to do with the speakers or added amps.
Fiberoptics have nothing to do with power they are light signals.
Only Logic 7 enabled head Units idrive and pro Rado use fiberoptics to the amp and you have to have the Logic 7 amp already for those signals to be active as the Pro Radio or Idrive has to be programmed to output those signals and they are mostly only compatible with the Logic 7 amp.
Its been a long time since Blaupunkt has even been mentioned around here.
If they are using there own plug and play connector it would be impossible
for anyone to help without the wiring diagram.
https://www.e90post.com/forums/attac...1&d=1411521234