If I understand the OSB-1 correctly, it is designed to run without a receiver or power-amp with two digital optical feeds, a digital coax feed and an analog feed with no provision for either HDMI or amplified input.

Unless you are using it for a center channel speaker (seems like overkill), or your bedroom system require more than 3 inputs, I don't understand why you would pair it anything. The 975 does not appear to be a great solution to feeding the OSB-1 in any case, unless you only wanted the OSB-1 for stereo.