Hi Christian,
Yes, you are quite correct that you only need two RCA plugs to get the stereo signal out of the Powerlink socket, but if you have a "generic" cable that is of an unknown purpose, having four RCA plugs fitted is usually a "guarantee" that two of them will work!
However, the best option is always to buy a dedicated cable for the purpose, then you know that you have the right connections. I can provide a Powerlink to RCA cable (see my banner at the foot of the page for details) that gives you both left and right audio channels from one Powerlink socket. When using this type of cable, it is easy to integrate the additional speakers, as the volume sent to the non-B&O amplifier will be controlled automatically by the B&O source. This means that once you have set the volume on the non-B&O amp to a suitable level, the speakers will always be at the correct volume to match the B&O speakers.
I suspect that when B&O developed Powerlink back in the 1980's, they were aiming to prevent integration with other brands of equipment, but it is still easy to combine B&O items with other products in almost any combination with a little bit of thought!
Best regards,
Steve.
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