Hi there,

You need an 861 with the IE42 input card, which I think was the standard input card from the v3 model. It has the requisite multichannel digital inputs for use with an HD621. Earlier variants of that card, such as the IE16 on the unit you mentioned, can't do this. You'd be limited to two channels only from the HD621 if used with this card.

You are on the right track with the two analogue output cards though (the OA12s). Later versions were the OA03 unbalanced, and OA13 balanced cards.

You could also skip the HD621 if you found an IA45 multichannel analogue input card. Direct analogue connection from your BD player to the processor, although an all digital path via the HD621 would offer better performance. The IA45 will also require at least a v3 861 though.

Cheers

George