Jim McShane is terrific. Another is Andy at Vintage Tube Services. I once bought a tube from him, got rid of the gear, never used the tube then called him up 3 months later asking if I could trade the tube in for another. He said no problem. Whether he's always so accommodating, I'm not sure, but he's definitely a great guy and has been doing this a very long time. First rate and full of integrity.
