Recommendations for Tube Amp Repair Tech in US?

I don't know where you live but if near St. Louis you should contact Zawwin on this forum. He runs a repair shop and I have been taking my gear there for 25 years.

I would recommend:
http://www.nosvalves.com

Over the years, I have had nothing but exemplary service on my Audio Research and Sonic Frontiers tube gear from Alex Lok, ace technician (35 years of experience)and owner of The Analog Store. What stands out and is uncommon in my experiences with obtaining service for audio equipment is the rapid turn-around time and the meticulous nature of Alex's work. Alex is great to work with and is an enthusiastic supporter of tube/two-channel audio gear. Check out Alex's website:
http://www.theanalogstore.com/

Response Audio in Endicott, NY may be able to help you. Bill is a great guy. He builds & mods amplifiers, big time w/tube gear, I believe tubes exclusively.

Please contact Kevin at http://www.upscaleaudio.com/. He is very tube knowledgeable and helpful.

It would help if you told us where you live. Nick Cowan at True Sound, Campbell if you are in the Bay Area.

Regards,