Service Shelf
There is one problem with the stepped desk – that comes when servicing or R&R gear on that top shelf. The answer is this “service shelf” gadget which is a ¾ hunk of plywood and some feat, combined with a couple of utility features. The service shelf has a set of “U” shaped brackets which slide up and are held in place by the thumb screws. The brackets serves to prevent the shelf from sliding away from the desk. The brackets slide up and down to allow the shelf to slide into position, and then be “locked down” by sliding the U-shaped brackets up into position and held there by the eye-screws. 
There are also screws on the back of the rear legs which slip under the upper shelf and prevents the service shelf from lifting upward as well. Between these two features, the shelf does not move around even with serious loads like this amp. And to prevent the service shelf from scratching the desktop, the bottoms of each leg, and the back side of the shelf legs have rubber feet. The rubber feet also reduce any lateral slip of the service shelf may exhibit. | 
