I am not actually using the phono input of the BM6500, I think it would just activate when the BM would have been connected directly to the main MasterLink network, when pressing N.RADIO on a remote somewhere. Same for the RADIO command – I assigned that to B&O radio on the Core and don’t want the BM6500 to start playing radio. With one BLC, my problem would be two sources to be activated at the same time.
I once read that Beojeff (USA) used 9 (nine!) BLCs 🙂