Do tube dampers really work?

Hee,
When tube is microphonic it's definitely bad. Dampers help to run that bad tube with more time "unaudiable". Try to compare readings on half-dead tubes using Hal-o dampers.

Karls,
If you remember I was posting about microphonics in tubes since I had them in freequent practice for quite a-bit working with powerfull UHF radio transmitter.

Tapping tubes is NOT a microphonic test since it exceeds air pressure gazillion times. I urge NOT to do that test.

What you can do is tap on chassis or interconnect wires and if you hear clicks-pops than you have a case with bad tube you need to examine.

As to dampers they eliminate vibrations of "bottle" but found tube coolers at www.percyaudio.com can prolong a tube life. Still not sure how it affects sonics since it's simply to say a teaspoon in the ocean to the different components speakers room, temperature and even air content.

On well designed tube equipment whether you knock or don't on tube sockets(in my case I can even knock on power tubes) it will have no microphony effect whatsoever. Whenever I spot some microphony from any of my tube components It's time to replace tube(s). The tube components I have is VTL MB100 monos and ARC PH3.
Pbb, in your case you're dealing with well-designed component that won't be affected with any tube dampers or any other such tweaks.