Vibration Control for Lightweight Tube Components


I'm looking for suggestions to isolate a lightweight tube preamp from vibration and resonance. Not acoustic vibration, but physical vibration from the stereo rack. When I touch the shelf the preamp sits upon, the sound can be heard thru the speakers.

I am using a heavy furniture grade stereo rack for my components, all using Herbie's Tenderfeet for isolation, including my TT. The preamp only weighs 7 lbs. and has Herbie's tube dampers applied, but needs to be decoupled from the heavy wood shelf. I've tried the Tenderfeet and Vibrapods under the preamp, but neither provided isolation from vibration.

So, what are owners of lightweight tube preamps and amps using for vibration control? (there is a limited amount of space between the shelves).
128x128lowrider57
One idea for the problem of heavy cables pulling up components is the lead/brass discs that a few companies sell. IMHE, they work well sonically especially when placed over power supplies. So often 2 discs does the trick, one centered to offset the cable pulling and the other over where the power cable connects. 

For vibration draining, another solution I didn't see mentioned in this thread is the ball bearing & cup type products such as Symposium Rollerblocks. They are very effective under my preamp and phono stage, probably under digital gear too. I thought these are pretty popular here, but since they are nothing new, perhaps there isn't anything new to say...Cheers,
Spencer
Spencer---Actually, in my post way up above I mentioned placing a trio of roller bearings (the generic term for what Symposium calls their Roller Block) between the pre-amp and Baltic Birch plywood shelf I suggested. I didn’t name a specific brand (such as Symposium) because there are a few people making them.
Since there are six count ’em directions of motion for which isolation would need to be applied and since springs isolate quite well in the vertical direction and isolate somewhat less well in two of the rotational directions and, practically speaking, not at all in the twist rotational direction or in the horizontal plane, a comprehensive solution would be mechanical springs plus roller bearings, which are rather good at isolating in the twist direction and the other two rotational directions as well as the horizontal plane, but hardly at all in the vertical direction. Voila!
Mass loading on top of a component is advised, if possible for its dampening and absorption properties. Something I have found most effective for this, I no longer know where to source. They were paperweights, leather bags filled with lead shot, used to hold down large architectural roll size drawings. Perhaps diving ballast bags would do the trick and be most cost effective.
@r_f_sayles, I plan on mass loading if I can find some weights that are only 2" wide. It made a significant improvement in sonics to my previous preamp. I’ve been looking thru my house and workshop for a DIY solution.
Maybe some calibration weights for a triple-beam scale. Too bad I got rid of my scale years ago, LOL.
Yes, I mass loaded my amp, pre, disc player. I used barbell weights with 1/8” cork bottoms. I didn’t have your spatial constraint however. I am sure you can find something at a hardware/farm store that would provide an inexpensive solution. Happy hunting!