Hi Richard,
If you are wanting to use the digital audio out from the B2, you'll need an external DAC with an optical input. This will convert the optical (digital) signal from the B2 to an analogue one suitable for your receiver.
The optical (digital) out on the B2 shares the same connector as 'Line Out' and uses a mini TOS Link connector. The cable you need for this looks like this -
Or just continue using the analogue connection, as it sounds like you have that working. Remember to turn up the volume on the B2 to 60.
Paul
Brennan Support.