Interesting - I had a similar result with solid state amp. Wooden platform had almost no impact on sound. Wooden blocks in place of amps rubber feet and placed on polyethylene board = little but slightly less appealing effect. Amp's rubber feet directly on poly board with the board on metal blocks on shelf - slightly better.
For all other applications (speakers, CDP, TT) I use wood - maple, ash and bamboo. The applications of these materials are driven more by cost, size available and aesthetics of a each piece, rather than focusing on the particular variety for given use. As long as the wood is fairly hard, it seems to work pretty well, again the thicker the better. Someday I may get around to doing an independent test of Mapleshade's claims for NA maple.
On a related note, I have tried Sorbothane dots directly under my gear, and used it to isolate shelves from stands and heavy wooden platforms from shelves. In these applications, I was not happy using the material to decouple equipment from whatever is directly supporting it as it seems to suck some of the life out of the sound. But I am happy using this material to decouple the platform from the shelf, or the shelf from the rack (can play system louder through room speakers before compression or distortion sets in).
This leads me to believe the purpose of the wooden platform is to drain INTERNALLY generated vibration away from your gear, while the purpose of an elastic material like Sorbothane is to decouple or isolate your gear from room vibrations originating from your speakers and transmitted to your gear through your rack. I say this because the benefits of the wooden platforms and anything you put between the platform and your TT or CDP (e.g. wood or metal blocks, cones, Sorbothane, etc.) are clearly apparent even when using headphones, and so must be interacting directly with the gear irrespective of room vibrations.
Finally, for your tube amp, I would think the platform material is a more critical factor than it seems to be for my SS rig. Since tube amps generally have big transformers, they can generate a significant amount of vibration on their own, and since the tubes can be affected by both internal and external vibration, I would also experiment with heavy wooden platforms and spikes/cones/Sorbothane as well for that application.
For all other applications (speakers, CDP, TT) I use wood - maple, ash and bamboo. The applications of these materials are driven more by cost, size available and aesthetics of a each piece, rather than focusing on the particular variety for given use. As long as the wood is fairly hard, it seems to work pretty well, again the thicker the better. Someday I may get around to doing an independent test of Mapleshade's claims for NA maple.
On a related note, I have tried Sorbothane dots directly under my gear, and used it to isolate shelves from stands and heavy wooden platforms from shelves. In these applications, I was not happy using the material to decouple equipment from whatever is directly supporting it as it seems to suck some of the life out of the sound. But I am happy using this material to decouple the platform from the shelf, or the shelf from the rack (can play system louder through room speakers before compression or distortion sets in).
This leads me to believe the purpose of the wooden platform is to drain INTERNALLY generated vibration away from your gear, while the purpose of an elastic material like Sorbothane is to decouple or isolate your gear from room vibrations originating from your speakers and transmitted to your gear through your rack. I say this because the benefits of the wooden platforms and anything you put between the platform and your TT or CDP (e.g. wood or metal blocks, cones, Sorbothane, etc.) are clearly apparent even when using headphones, and so must be interacting directly with the gear irrespective of room vibrations.
Finally, for your tube amp, I would think the platform material is a more critical factor than it seems to be for my SS rig. Since tube amps generally have big transformers, they can generate a significant amount of vibration on their own, and since the tubes can be affected by both internal and external vibration, I would also experiment with heavy wooden platforms and spikes/cones/Sorbothane as well for that application.