The bass Amuser is an overdrive pedal specially for Bass. It was develpoped in the "Musiker-Board", a very large german music instrument forum. Credits go to the user "AK" and "elkulk" who had done the theoretical and practical work.
Here is the link to the thread, where you can also find fantastic building instruction, the text is only available in german:
Workshop - Bass Amuser
This kit contains all parts to build the Bass Amuser, so pcb, 18VDC power supply and an undrilled BB enclosure are included!
Knobs are not included, you can select the ones you like best in the shop. You can use all knobs for 6,3mm shafts a diameter up to 14mm. Also not included are sheets to label the enclosure, those also can be found in the shop.