Send it home to ARC. 213cobra is right, ARC makes minor changes as they go. They will sometimes incorporate these updates in your piece while it is being repaired. They did with my Ref 5se that was under warranty. They will also make sure that it is working properly and sounds as good (or better) than the day it left the factory. It is worth any extra time and expense to have it done right.
Repair resource for Audio Reseaerch Ref 150 amp
Can anyone suggest a service repair resource for my amplifier?
Thanks
Shaq