The JB-940, I'm not so sure,... is it a component-style unit?
I think it is, also, I'm fairly sure the JE-470 is also a component-style unit.
These Sony MD units have analog RCA/stereo in's & out's, plus some models accept S/Pdif and optical inputs/outputs. Get the minidisc media, & it functions basically the same as a cassette recorder. The 2x & 4x record mode, as well as mono recording, is basically a sequential stepping down of recording quality, to raise the total recording time. The MD format I'm familiar with, runs hifi audio at [ATRAC encoded/data reduced format] 74 minutes of stereo per disc, also 80 minute minidiscs are now available. Actual data storage of the minidisc media is 140Mb, total, fixed, for a 74-minute normal stereo minidisc. [80-min disc/more].
Minidisc record quality is quite good. If you use it with a quality front end source, like an audio mixer, then your recordings can go live-to-stereo, on MD format. Too bad, but none of the Sony MD component style units I've scoped have had 1/4" mic inputs,... BUT,... I believe there are several TASCAM MD recorders that would have MIC inputs.
There's a 4-track and 8-track version of minidisc recorders for multitrack, and the standout units are the Tascam 564 Portastudio and the Yamaha MD8 portastudio-like device. However, these units use the MiniDisc-Data 140 discs for multitracking, which are more costly and harder to find than the normal stereo minidiscs,... but it's still a small, convenient, good sounding medium for multitrack, which is by far better than cassette. [Don't get me wrong,... I LIKE cassette!]
Minidisc recording is just plain fun.
Oh yeah, HI ~gas!
Minidisc recording is cool,... try it! Try mixing down to MD, or going live-to-stereo through a mixer in MD. Minidisc recording is fun & easy. I especially like the component-style MD recorders over the mini-handheld MD recorders. Those little discs are pretty cool, & way more convenient than cassette, & sounds better too, in most cases. However, unless your source material is primarily from, or targeted at, mp3's, then I'd stick the full-hifi, 74-80-mins of stereo.
Bye ~gas!