I bought the ultra max split limb limb saver noise suppressors. They are the ones that come in two pieces and screw together. http://www.limbsaver.com/archery/dampening.php You then unscrew the original Hoyt string suppressor/stop. The treads for the limb saver are the same as Hoyt. Screw on one section of the limb saver and adjust to within 1/8 of the string. Works great and real easy to adjust and i have had the same one for almost 3 years with thousands of shots.
I had a vibration when i had my original Hoyt stop on. Read a post in archery talk that year since a lot of Hoyt guys were not real happy with the factory stop. This is what they were doing.