I think the benefit of the SPDif is only really apparent when using the BL5 loudspeaker system. It may be technically superior to use SPDif in a wholly analogue system but how/where DAC occurs is beyond my knowledge. Also, the BV7 does not output digital sound but uses Powerlink system solely for that purpose. The BV7 can allow the input of four 2 or 5.1 digital sound and do something somehow with that signal. However, in context of this thread, that will result in the signal passing either back to either the Powerlink and/or the Masterlink board. Both of which are analogue pathways.
What I can state is that when using a BV7 as a Master in conjunction with BL5's, there is a configuration that does work to improve the sound quality significantly:-
BM1/BM5 Dig Out to 1st BL5 Dig In.
BS9000 Dig Out to 1st BL5 Dig In (Coax Y-piece needed if connecting 2 digital sources)
1st BL5 Dig Out to 2nd BL5 Dig In
2nd BL5 Dig Out to BV7 Dig In
i.e. the digital signal is as far as I am aware, activated when the audio source is directly placed into one BL5's digital input socket first and not in to the Video Master. You know this has happened as all the tone controls on the Audio/Video Master will become non-functional. Both the Masterlink and Powerlink systems will assist in terms of IR control and volume respectively.
It may be possible just to connect one audio source to one of the BL5's digital inputs, chain to the second BL5 and connect the second audio source to the 2nd BL5's output (disconnect the digital coax cable from the BV7) but I am not certain (read: have not tested) whether this configuration is uni or bi-directional.
The method above worked fantastically well with my BC2/BV7 and the BL5's. I will replace the BC2 with the BM5 and expect no need to change the configuration.
Hope that helps
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