There is no internal muting in the MCL2p,just power up/down,like in the Beolab 8000.The signal lines are muted within the Beocentre when changing source etc.I think it was only the Beolab Penta and Beolab 3500/4500/5000 that have internal muting.
I've used the MCL2p as a slave amplifier to drive speakers in a link room,and you can connect a MCL2a(Extra speaker kit)to the MCL2p,and then local muting is available within the relay box.Works very well.
It's a useful amp,and of course saught after.
Regards,
Nick