The X68000 outputs only in 31khz, 24khz, and 15khz RGB. Every game chooses it's own, and the system uses weird resolutions like 512x512 and 768x512. Some games even cycle between 31 and 15 during the gameplay itself, you really need a trisync monitor to get the most out of the system. Most recorders, and even a lot of modern monitors don't like the wacky, non-standard signals.
So yes, I use an old downscan converter. Which downscans the 31 and 24khz games to 15khz RGB and S-Video. I then feed the S-Video to my DVD recorder, which then rescales everything to 480p. So yes the quality isn't as nice as I'd like, but it's the only way I can record off the real machine. Pretty much every X68k vid on youtube is emulated, except mine and a cool Japanese dude.