Rab wanted to make a combo cab where the controls were at the front – i.e. with the chassis suspended from the top of the combo cabinet. This simple decision actually causes a lot of changes: the whole amp needs to be laid out in ‘mirror-image’ form (compared to the layout shown in the online construction manual). It’s not hard, but it needs VERY good attention to detail. Rab also chose a distressed paint finish for his cabinet, an alternative worth considering for those (like me) whose tolex-covering skills aren’t up to scratch!