I have a ROLLS HA43 PRO 4 Channel Headphone amplifier and I have hated how it sits on my desk. It never stays where I want it, and is a pain to see what the volume is set to.
This weekend, I took some time in Autodesk Fusion 360 to design a tray to mount the HA43 to my monitor post. After a couple of test prints, and filament spool changes, it is finally printed.
If you have this amp, and a 2" (51mm) monitor post, you can download the files from Thingiverse.