goldmund amp

Hi, I have goldmund mimesis 8 amp having trouble. When I turn it on it sound fine for about 10min then one channel
just make hiss noise. I tried swapping cables and speakers,
and it's always same channel. Now problem is when I cotacted local goldmund dealer he said it has to go back to Swiss to evaluate the problem. Does anybody know who can service Goldmund? I am in Boston,MA area.
You will probably have to send it to Goldmund, but I think they can repair it here in the USA. Speak with Ty at (phone) 818/774-1031 or email him at