The only digital DVD-A ripper that I know is the WinDVD7 plug-in that, I believe, was yanked from websites, presumably for DMCA infractions.
The best "rips" of DVD-A's that I have are playbacks fed to a quiet tube linestage, and rerecorded as I need, most often CD 16/44.1
The linestage warms up the recording just a smidgen, and the overall playback is much more enjoyable.
The beauty of it, is that by going analogue, you are allowed to may a personal back-up copy and thus aren't breaking the DMCA, to the best that I understand.