First, did you hear a sonic improvement with the amp stands and audio rack?
If you want to improve the sound of your components then I would look to Townsend isolation devices and even more, Silent Running Audio platforms. These will contribute to the sound quality far beyond wood racks or shelves. I believe the best use of funds is a good rack (without integral isolations devices in it like your racks) and isolation devices under the components. Isolation devices are likely to have the biggest impact on turntables, tube amps, tubed DACs / CD players, then tubed phono stages, preamps , other tubed components and then all solid state components… in roughly the same order.