Some manufacturers always have to slightly differ from the specs, creating a nuisance like this one. By no surprise, Sony is a common brand, with DV issues. There are several high-end JVC professional DV "VCRs" (VTRs) that won't properly play back Sony-made tapes, either. Unfortunately, the JVC VTRs were often blamed for being "bad quality", but the Sony DV cam was the real culprit.
You've verified the Samsung camera is fine, both in its ability to play the Sony-made tapes with analog out (and on-camera analog preview playback), as well as playback AND export of its own Samsung-made tapes.
Therefore, the Samsung camera is probably perfectly fine.
The issue seems to be in how the audio was stored on the tape by the Sony. Although DV is supposed to be standardized, I know for a fact that this isn't always the case. There are a lot of little loopholes, be it via codecs or other things.
I've seen this problem posted in forums many times through the years.
The only fix is to use another Sony DV camera. It doesn't even need to be the same model -- it just needs to be a Sony-branded DV cam, according to most reported "fixes".
Here's an example of several people reporting the same issues as you, discussing how they've tried all kinds of software fixes, with the only working solution having been use of another Sony DV camera.
So track down a Sony DV cam. Either borrow one from friends/family, or buy one used from
Amazon or eBay.
Your only other option is to do analog output from the Samsung camera, since it seems to play analog out correctly (from these Sony tapes), and then use a DVD recorder or capture card to re-capture the video. This is not the best option, but if you use lossless/uncompressed AVI capture, or 1-hour XP mode DVD recorder recording, then quality loss should be minimal.
