How thick is the limit?... never heard anyone say?

Krellman, thanks for asking. I actually haven't found anything I like better. My attempt at a joke, above, was meant to convey that 4 inches was a bit too much for me aesthetically. The Mapleshade site mentions even thicker ones as possible and effective, however.

I trust my supplier when he says 3 inches is better than 2, yet my personal audio guru says two is enough. I haven't done a test to find out who's right, since that would cost me a little cash. Instead my rule of thumb is, if it's two inches or more and stable, it's good enough.

As for "I had", that's in the past tense because I sold my Shanling amps to one gentleman and the platforms to another. I hope to have another pair of 3-inch platforms, sized for the new amps, in a month or so. When I get them, I'll report my impressions on my system page.

I may be the exception, but I found 2 1/2" maple butcher blocks to be slow and muddy sounding. They made my system sound terrible. I would suggest trying them before you buy them if possible.

One thing is for sure. They definitely make a difference. This is not a tweak that you have to carefully evaluate to hear the difference.

I suspect they may be great in a SS system if one is looking for some warmth, but in my tube based system they simply didn't work.

I have three brand new John Boos butcher blocks if anyone is interested! ;)

Markphd, I think you are wrong when you say "thickness is irrelevant".

Thickness will change the resonant frequency of a mass of wood. I am not saying for better or worse, just that it will change.

Isn't resonant frequency related to mass? More mass=lower Fr.

Also, wood being a 'natural' composit will have the resonant modes distributed so there will not be one 'bell like' peak.
You are correct that speaker builders take advantage of this.
However, a panel of wood used as an enclosure is different that a wood base for a component....for one thing, the pressure stress is applied fairly about all sides, not just the pressure from within an enclosure.

If you seriously want to damp out a wooden shelf, laminate on a sheet of something inert, a very hi density rubber/plastic over a sheet of metal....maybe 3mm of aluminum. Bond it together with a uniformly applied adhesive. Such panels are nearly inert.

Don_s, I will defer to your comment. I will refine mine by saying that thickness is irrelevant to the fact that any material will resonate. Making it thicker or thinner or longer or shorter will not stop it from resonating if you hit the right frequency.