Been experimenting with glass shelf/ball bearings under various things on my oak hifi racks podium slimline, worked well under turntable, too lively/harsh/fatiguing under the pre amp and the cd player but there is definitely something worth exploring. Currently using the glass shelf with some Atacama gel speaker stand feet and they work a treat.
Was wondering if anyone has tried just using some sorbothane feet directly under their CD player, or are the standard feet pretty decent?