Mass and vibration cancelling on top of CD player?

The VPI brick is an electromagnetic device. Roxy54, I have a sneaking suspicion Rja was pulling your leg.

+ 1 for how Zd542: mass and build quality matters

" ... My best guess is that the combo of cones and the book dampens the CD player from vibration. Keep in mind, though, I said mass market. It worked on a cheap Pioneer Elite universal player that weighed about 2 lbs. The same tweak has no effect on my Wadia. It already comes with cones from the factory and weighes a little over 50 lbs..."

My REGA ISIS Valve cdp is also around 45+ lbs., and these types of tweaks have no effect.

Similarly the Mapleshade 4" maple block platform and Heavyhat Triplepoionts brass cone footers were also bust with it. Again it works with my B system ARCAM kit.

Instead what did have a profound improvement effect was an introduction of a premium audio rack. In my case, a custom bespoke modded rack patterned after the NAIMFRAIM)

Geoffkait,
I am well aware of what VPI bricks were designed for. I have had four of them for at least 20 years. I use 2 on my amp transformers, but they are also very good to use as a damping weight for a case that might otherwise be a bit buzzy.

ZD. I put a heavy book on a marble tile (on a piece of heavy cloth to protect the player)(no cones) on my Lexicon RT-20 and have been "very" pleasantly surprised. I was using a very "average" CD-- Portrait of John Williams (MK37791)-- as my test.
There had been a very minor degree of harshness in the higher treble notes that I had attributed to being the sound of his guitar (I should have known better-John's ear would probably be as sensitive as that the most ardent audiophile). With the added mass the harshness was gone! The CD all the more enjoyable. Without question this was due to "damping of the vibration to the player caused by the rotating disc" as there is absolutely zero vibration transmitted from the speakers to the player.
The added musicality on strings, as well as orchestral, is very much appreciated. I have exceptional separate ac isolation/conditioning for my pre, amp and the RT-20 and I probably am in a better position to evaluate this effect than most as I'm also using reference Spectral & MIT products. There is no question of the result-so I guess this confirms why the serious attention paid to ridgidity and mass among the high end players. I of course will now look to further avenues for sound improvement as I am not able to buy an Esoteric, Wadia, Spectral or other top CD or combo player at this time.
Any suggestions on my next experiment?

Making the chassis rigid doesn't prevent the disc from vibrating, which in and if itself is not too good for the sound. One way to ameliorate disc vibration and flutter is to obtain absolute level of the disc while spinning. Not as easy as it sounds.