Tube damping?

It is very important, tap on any tube with your system powered up and you will hear the ringing clearly in the speakers. I haven't seen anything I would consider highly effective but maybe others know better. Even an O-ring around each tube is better than nothing. The constrained-layer damping sheets probably have the most potential. A thin layer of viscoelastic damper covered by a thin sheet of aluminum, could be cut to size with a scissors and wrapped around the tube. I'd like to know if anyone has tried this, and what the results were.

Common wisdom is that the driver tubes may need damping but not the power tubes. Kevin Deal advises stongly against tapping on tubes as this could make exaserbate (sp?) the problem by loosening other components inside the tube. I bought HAL-Os and they seem to work well and they are not expensive but hi-tech at the same time.
http://herbiesaudiolab.home.att.net

I have used both the Ensemble Tube Sox and the Top Hats for my small signal tubes, neither of which are inexpensive. I find the Top Hats to do a better job of focusing the sound and images; the effect is not huge but makes a difference to me. I think you might want to try the Audio Research small signal tube dampers, which are pretty inexpensive and are reported to be effective; at least that way you won't be out an arm and a leg if you don't notice a difference. I have not tried any dampers on the large power tubes I've used (6550s, KT88s); I know of none, and my practice has been to isolate the amps themselves from vibrations instead. Good luck!