Amp Stands - Wood or Stone

@noromance Yet there are limits, whether one likes it or not. Challenge those limits at your own risk. As far as humans are concerned we are way more alike than different. We have yet to see a human with three ears and hearing much beyond 20 kHz is impossible for use, but not for some other critters. Humans can not see with their ears, but bats and whales can. 

@dmk_calgary What you are trying to do is make a constrained layer construction to minimize resonance. It might work great for a turntable plinth put it will do bupkis for anything else.

Many of you have subwoofers with amplifiers installed within. Sealed subwoofers have extreme increases in internal pressure with loud bass below 100 Hz, yet the amps seem to do just fine. An amp out in the room is subject to a lot less. 

Whatever you make your stands from, put your components on Symposium Ultra platforms. The disc couplers transmit any vibration from your equipment or the room and converts it to a tiny amount of heat. I have these things under my components and the difference was remarkable - especially with my tube amp and preamp. Cleaned everything up.

If cost isn't an issue, get the Symposium Osirus rack.

Symposium Acoustics: Products (symposiumusa.com)

Some of us have our favorite brands, for me it’s HRS and Core Audio designs, both deeply rooted in both physics and sharp listening skills. Some of us also have a DIY bent. to the OP you would be wise in your adopted approach to adopt the constrained layer approach suggest by @bdp24 and possibly incorporate a top plate of Panzerholtz. Wishing you all the best on your project….in music

Jim

I forgot to credit @pindac w suggestion of tankwood…. very nice stuff…makes a wonderful armboard also….

The clue for finding a wider range of Board Material produced very similar to P'holz and Permali is searching for the following:

" Phenolic Resin Impregnated Densified Wood Board "

Some Companies using these Board Types give the materials an in house name, hence, Kaiser Speakers calling P'holz 'Tankwood'. 

As a guide to purchasing these Board Materials, the Board must be a Heat Treated Vacuum Compressed Board, which has a weight of approx' 1400Kg/m3.

There are PhenolIc Resin bonded boards that are not produced the same, the Boards can be produced as a non heated treated Vacuum Compressed and seen with a weight range from 800Kg/m3 - 1400Kg/m3.

When selecting a Board Type that is approx' 1400Kg/m3, there are a few other considerations.

The individual who originally tested and made public their measurements, which is where the interest started in using this material for Audio Purposes. When describing their test results and the attraction of the material, made it known that a 10mm thick board has all the intrinsic properties required to suit Audio purposes.

The Boards Tested have evolved in their construction and thicknesses and in general, it is accepted that a Board constructed with Cross Grain Plies, a 1mm Ply compressed to 0.5mm, where the commonly selected Board thickness seen selected today is 25mm ( 1"). A Board will typically be Cross Grain Plies using 50 Layers @ 1mm compressed by 50%.