Hi - I think you are trying to connect the new BV6 to the BS4 as a replacement for the MX7000 ?
And you want to do it without having to upgrade the BV6 by having the MasterLink system module added ?
This takes one down the path of trying to link one unit's audio out to the other unit's audio in.
I presume your speakers are attached to the BS4 ?
The BS4 has an AUX-IN, so the question is how to get the audio out from the BV6 into the AUX-IN of the BS4 ?
First B&O (1976) was a Beogram 1500 ... latest (2011) change has been to couple the BL11 with the BL6Ks *sounds superb*