I am dealing with Audio Doctor (Cornell Smith) for over 8 years now and almost each component of my high end stereo set-up has been on his bench either for repair/adjustment or upgrade! He did an impeccable job on both, domestic (McIntosh, Furman) and import (Sony, Classe, Technics, Canton) brands, at very reasonable cost. In fact he provided me with valuable advice at no cost, saving me substantial expenditures, had I have listened to other "experts". Cornell has a remarkable expertise in both, tubes and solid state equipment, including valuable "antique" examples difficult to procure parts for.
A professional of rare integrity, Cornell has also a pleasant and helpful manner, taking his time to explain the problem even if the client happens to be a neophyte.
Most definitely the best address to go to for the whole range of audio equipment! Lucky to have someone like him in the Valley!