This pretty much covers it:
Once it was no longer available for DIY, the info was withdrawn from public view. Those who bought it as DIY when available had access to the necessary info. I believe it is also the responsibility of anyone selling secondhand DIY circuits to provide the tech docs to any new owners, since they are not available any more.
Roger can, of course, correct anything I got wrong there.
Construction information for DIY projects, including the MS Mid Side Matrix, Elliptic Equalizer, Mastering Console, Phono Transfer System, Insert Switcher and the Dual Class-A Amplifier. You can post your baby pictures here.