This is apparently not really a traditional muff and has a few interesting things going on.
http://www.freestompboxes.org/viewtopic.php?f=1&t=20612&hilit=germanium+big+muffAll three schems are there. Might be nice to have the OD and Distortion on separate boards for 1590B flexibility. If they end up fitting on a single 1590B board I guess it doesn't make much sense to have them separate...