Question about Yamaha Bd-S681

The BD-S681 has both analogue RCA audio outputs (left + right) and digital outputs optical and RCA. Check which of these connections are available on your amplifier/preamplifier. If there are several to choose from, the digital ones are preferable.
As the unit is designed as a Blu-Ray Disc player, a TV or Yamaha AV Controller software (free from Yamaha website) for tablet/phone may be helpful in setting up.
There is also a remote control included in the delivery.
In contrast to simple "CD only" players, this unit is not very fast to operate, but its sound is excellent.