Repair mingdac mc3008c mono amp?

Did anyone know where I can send Mingdac mc3008c mono block for repair, Pacific Valve was close business, I need help?
one of the amp- when first turn power on there was popping sound coming speaker, and right after relay click, then the front meter jump increase 1/4 and been stay, but unit still playing normal sound, with no distortion.
Have you tried replacing the tubes first? Always first suspect in tube pieces when there is a problem. Just swap the tubes from one amp to the other. If the problem follows the tubes, you just need new tubes.
If it stays in the same amp, then you can take it from there.
Yes, I swab tube from other amp still same problem 300b and 2a3. Then there was recommend repair from Pacific Valve web site send to Delectronic repair. They told there was nothing wrong, I'm not sending unit If there was nothing wrong. I think I need to find some where else ready able to fix Mingdac product?