I use the UltraSonic Rx-9 on all the 6H30 tubes in my system with great results. I have had them for years and they still look just like new. I don't use a tube damper on the 6550 tubes.
Tube temperature for ARC Ref 6
I am considering purchasing Herbie Tube dampers. Was wondering if anyone knows the tube temperature for (6) 6830 tubes and the 6830 and 6550 in the power supply. Herbies Ultra Sonic tube dampers temp is up to 482 degrees. And HAL-O 111 is excess of 1000 degrees. Im wondering if i should just buy all of them that are up to 1000 degrees.