Sure u can ,, Optical supports dd and dts . and my audio only shows 2 channel in windows....
So what i did with my kodi ,,,, First in the audio output in kodi , put the setting level to expert ...
audio output , you optical device
number of channels 2
output configuration , best match
stero upmix (check it) so u can play like series that are 2.0 , it will upmix it to all speakers..
maintain origional volume on downmix ,, not checked
enable passthrough (checked)
then choose your passthrough device ,, your optical device
dolby digital ac3 capable receiver enabled
enable dolby digital ac3 transcoding -- dont forget to check that on
dts capable reciever enabled
I have an old reciever and had alot of problems to get it working...