Designed in OnShape.
This will allow you to rack mount your SB500H into a 19" rack that is 12.25" deep similar to the Gator 3U that I use. I know it seems counter-intuitive, but I originally had a larger 2U Ampeg head in there until it died out. I also do lots of gigs that I use my headphones as monitor (hence headphone amp) so no need for a cabinet. This setup is VERY lightweight.
If you have another small amp like this that you would like some brackets made to fit, get in touch. Just a few basic measurements are needed.
I printed this in PETG with a high wall count, with a 0.8mm nozzle. Very strong! If you print with a 0.4mm nozzle, do at least 5 perimeters and 50% infill and increase your line width to 0.6mm. I've included some small washers that are a nice tight fit for #10 or M5 mounting bolts. Print these at 100% infill out of PLA. The two front brackets can be printed together on an Ender 3, but the rear two need to be printed separately.
When installing the brackets, SLIGHTLY loosen the phillips head screws that hold the rubber feet on the amp. Apply a bit of lubricant (dielectric grease is what I used) to the inside of the holes and slide them on, then tighten the phillips head screws back up. The holes are sized exactly to the relaxed rubber feet. Install all four, then rotate the rear ones inward slightly. Insert from the front of the rack upside down and tighten the front first. Then do the back.