Do tube dampers really work?

Tube dampers are relatively cheap; but will they REALLY improve the sound of my Audible Illusions preamp?
Another vote for Hal-o tube dampers. They worked for me in my preamp. Cheap too.
I am also in the Herbie continuim...nice little tweaks, bout' half way down as well..
I am using Shun Mook Valve Resonators, which are more than tube dampers, on the input and output tubes. I could not believe they work pretty well on my system (Berning amp) with more musical, lively and lush but detail... The Valve Resonators can adjust the sound you want. I will try them on my preamp later. Good luck.

I couldn't tell the readings before and after using the Hal-Os. You may want to contact my friend (in Germany) if you're really interesed. He could be reach at

FYI he's a honest tube seller and he has to measure tubes, to grade the good tubes and to scrap those bad tubes. He measures tube parameters and microphonic. So I sent him 2 sets for measurement of microphonic reduction.