Large brass devices on top of power amps ?

Browsing through photo gallery of several systems I have seen several amps where a large brass disc are placed on top of the amp.
I would really like to know what are the results adding these brass devices.
You raise an interesting point,is this theory or based on personal experince? is there some optimal weight/size that would dampen some component`s tendency to ring without harmonic supression? I agree that harmonic information is very vital and it`s absent is noticeable.
If you need to put weights on equipment to stop it from ringing,the equipment must not be designed very well.Just my opinion,nothing more.
Leave it to audiphiles to complicate a very simple concept. All the MASS is for is to dampen/reduce vibrations getting to the electronics. So use something that has a lot of mass (a baggie of lead shot comes to mind - don't eat/breathe it) and will couple well to the item it is sitting on.

You could even use a heavy statue or even a rock that has a flat broad base to accomplish the same thing. Dyna-mat type material or sorbothane will provide good coupling. Or just keep it simple and use felt.

Also, do what car audio enthusiasts do with stuff like dyna-mat to kill vibrations. You can line the inside of the chassis to accomplish this. Don't block the vents!

The use of small pucks and disks are for the psycho-acoustic crowd - they work great if you think they do.

And to think everyone said we shouldn't stack components;-)
I use edensound stuff from Vermont Audio - very well made and not to expensive - on the other hand I'm not at all sure I can hear a difference on my EMM Labs CD Player or Atma-sphere preamp - so either the gear is designed well, or I don't hear well enough to pick up any noticeable difference, but they look nice and offer proof of my audioneurosis bona fides.
I don`t know who`s complicating anything, some components are built with thin chassis tops that could possibly benefit from mass dampening. Listener57 raised a good point regarding the detriments of over dampening, just a factor to consider that`s all.