Some of us are having a out of phase issue with the GK MB210. Here the fix of you're confident you can hand it. I had the same problem and didn't want to send it back so I fix it myself and now it rocks with the extension speaker hook up. Beware you may void your warranty.
My MB210 was the same way, it's out of phase. I fix my myself by opening the chassis and revering two leads.
The leads was from the main board to extension speaker output , it has a two conductor jack on the right side with just two wires (black) attach to pin 1 and 2. they have to be revere, you revere them by pushing in the small metal pin and pulling it out at the same time. Do one at a time.
My MB210 was the same way, it's out of phase. I fix my myself by opening the chassis and revering two leads.
The leads was from the main board to extension speaker output , it has a two conductor jack on the right side with just two wires (black) attach to pin 1 and 2. they have to be revere, you revere them by pushing in the small metal pin and pulling it out at the same time. Do one at a time.
