What are all these metal cans/pods sitting on top of electronics?

Brass is a popular audiophile material used for damping electronics (and as footers under electronics and speakers). Brass weights with a thin cork or elastomer backing are sometimes used to reduce resonances from undamped metal chassis tops covering electronics.  Some use them on top of speakers to drive cabinet resonances to a lower frequency or to damp flimsy/thin speaker cabinets.

I’ve tried Herbies Audio Lab Stabilizers (or two stacked). Pre, DAC or ss amp, but I always end up removing them after some time. Same outcome every time; a bit more clarity and delineation but slight negative affect on soundstaging (within, not overall size) and also a slight loss of the organic flow I have... It’s a fine tuning tweak that not all systems need or can benefit from. 

VPI brick blah blah honk honk.

 John Darko no.

The community will benefit from my most recent article for Dagogo.com just submitted a day or two ago. It will take on the subject of mass loading and several other tweaks. 

mass loading can help some equipment, can affect SQ

but as mentioned below... lots of streaming gear (and some phono stages) are small and light, need something on top to hold them down so cables can be attached securely and don’t shift stuff around