Repair of Cayin HA-2 tube headphone amp

I have a Cayin HA-2 headphone amp which worked for several months, until the audio sound became almost minimal. You can still hear music, but just barely. This may be a problem with the volume control. Does anybody know a reputable repair company with experience to handle this kind of problem?

Best to ship it back to Steve, the Cayin USA distributor. Steve always provides the best customer service. He will most likely do the repair himself, and is an expert. Go to the CayinUSA web site and e-mail him. I've visited with Steve many times and I am sure he can take care of your problem, at reasonable cost.
You have to send it back to China where it was manufactured.
Rrog, And you know this how?

Hayw, I agree with Buconero. Contact the USA distributor.
Have you checked the tubes? If you don't have spares I would first get some and swap them out before sending the amp in for repairs.
Thanks for all your responses.

Steve may be able to fit my repair in his schedule but maybe not. If for some reason, he is not available, any other ideas who has the expertise to do the repair?

As to the question about tubes, it is not a tube issue, as I tried more than one pair without any improvement.
Steve the Cayin USA distributor is too busy.

Does anybody else have any other suggestions for repair?

I would google a repair facility close to where you live. Try it on yelp or some other site that rates such things. Or google high end tube repair shops and hopefully something close will come up.

This has been done already on other threads and there are some very qualified folk out there that can diagnose and do the work.

All the best,