Best tube dampers that you have used


I currently have a Thor Audio monoblocks TP-150, 8  EL-34's Sovtek tubes for each amp.
Was wondering in anyone's experience will tube dampers improve the sound quality.
Am hesitant to proceed as I have read that  tube dampers can melt from the heat of the tubes and sometimes
cause smoke. Any thoughts would be appreciated.  
128x128kjl1065
Herbies Ultra Sonic RX is by far the best with just enough damping for small signal tubes.Many dampers over damp these do not.
kjl1065
I have read that tube dampers can melt from the heat of the tubes and sometimes cause smoke.
Who's made that claim? I've never heard of it happening.
Herbies HAL 03s  are for very hot output tubes and they will not melt or deform .They will improve the sound as well.Enjoy!!
I've used Herbies for small and large power tubes and, frankly, I honestly can't tell the difference. I've gone back and forth a few times, no difference. I leave em off now so as not to compromise cooling in any way.