Try capturing either blackburst video or timecode on screen video next to your sound then use the feature in your editor software that lets you dub audio editing without dubbing or mixing wrong video. It`s the most regular of the different ways.
it is not very convenient because audio dubbing can not be used in a batch mode.
I have DigiBeta tape video with audio recorded, but i need capture only sound from this tape in bath capture - 10-20 small parts must be capture in separate clips. Older version Premier CS3-4 and older version decklink driver success capture audio without video.