Hi and welcome to Beoworld! I had a look at the circuit diagram (available to paid members) and the Powerlink Outputs are taken from the pre-amp stage (after input select, vol/tone control and muting).  They do not go through the 'Output Amplifier' which supplies the speaker outputs.

Thanks! I just found the schematic, and yes I see now, the pre-amp outputs are fed through 100Ω resistors to pins 3 & 5 of the Powerlink sockets.

Novice question for the electronic experts here: Why the 100Ω resistors?  Safety load to prevent shorting?  Impedance matching, i.e. a dup of some 100Ω later in the amp circuit?  IOW, what differentiates the amp next-door in the chassis from an amp down a few meters of cable inside the speakers?  When running line-level output around the room, why would one reduce the already-low output?  For that matter, I guess the same question is why you can't hear the plugging-in of Powerlink speakers dropping the volume level to the main out speakers.  Basic I'm sure, and I heard "output impedance low --> input impedance high" for line-level amps, but don't *truly* grok else I might understand the resistors...  TIA.

It's probably to prevent external loads from affecting normal operation of the internal power amp (and speakers connected to it).