That DC offset circuit itself could be at fault. Amplifiers cannot be diagnosed over the phone with non-tech customers. Don't waste your time troubleshooting, send it for warranty repair.
Just to be sure, check to see if the wall receptacle is operating normally. 120VAC on the hot, very little voltage on the neutral and nothing on the ground. If the ground is showing voltage, that will definitely impact an amplifier with microprocessor controllers.
Also, are you using the Kensington's earth ground? If so, disconnect it and see what happens.