Those dampers are suppose to be put in that position normally. They do not belong over the plate structure of the tube.
Tube dampeners on ARC gear ... FREE TWEAK
Here's a cheap (free) tweak for owners of ARC gear using the black tube dampeners. If you move both dampeners as far up toward the top of the tube as possible without having the top one fall off, taking care that both dampeners are solidly touching each other, you will get better dynamics, bass, mids, highs and a lower noise floor. Try it ... you'll like it.