An AV rack is not just a piece of furniture .... It MUST perform the additional task of Isolating each electronic component from vibrations.
The Metal spikes that you see are not optional extras, they are ABSOLUTELY ESSENTIAL to the design (assuming that mind has been applied to create a rack that will isolate vibrations.
* Metal Spikes
* Special Platforms (Select wood like Bamboo, Multiple sandwich layers of wood and elastomers)
* Completely Suspended Shelves
* Sand Filled Hollow Posts
These are just Some of the measures used to create a True AV Rack. ... Else its just furniture.
As a first move, try putting a Bamboo Chopping board, under any piece of your Hi Fi it may be under ... a TT, DAC, Preamp , or what ever.
Hear a difference ? If yes, take the pursuit forward.... After All Hi Fi is our hobby, and its a pursuit to get the best sound possible