[Five]

well, your md recorder (like all of the older ones) can only record in lossy, its a codec called atrac and its just like mp3.

as for getting the best transfer of this show, see if there's a 'line out' jack, or if not maybe there is a setting in the menus to change the headphone out to a 'line out' (I have this on my MZ-NH1). I don't think you can do a direct usb dump unfortunately but you could ask over in the forums at minidisc.org, somebody will know if this is possible with your model.

you don't mention your soundcard, so I'm guessing you need to get something better quality. the ones built into computers are pretty much garbage, as bad as it gets. grab an m-audio audiophile2496 (about $120) or similar to up your quality (also improves playback sound and supports 24bit).

if you're still stuck with the headphone jack, you might consider fixing the massive dc offset problem (effects>amplitude>amplify>center wave preset), apply it to the entire show as one large wav and listen to it against the original to make sure it is helping. or borrow a friend's MD unit that has the proper 'line out' and this together with a quality sound card will give the biggest improvement in transfer quality.

also consider getting a lossless recorder! its really worth it, sound is much better.