Hi and welcome to our friendly forum!  Hopefully we can help you get set up and connected. To answer your question about which ML source should connect - it doesn't matter!  In a masterlink setup all the masterlinked components are connected in parallel - effectively they all share the same connections.  If you have a spare socket on the distribution box then you can connect to the NL/ML converter from that. I think that when you come to set up the NL/ML Converter, you will have to set it up as 'Source Centre' because you already have a Videomaster (the BV10) and an audiomaster (the BS3000) on your ML system.   However, my experience on NL/ML Converters is quite limited so please have a read of the setup manual (do you have it?) and try to work out what is best for you.  I am sure that other forum members will be able to advise further. Good luck!

Thank you for your quick response. The receiver is on its way to me; as soon as I'll have it I will set it up like this.