If the Clean Channel of the AMP1 Mercury Edition is turned down very far and the overdrive gain is turned up very far, a slight cross-fade of the overdrive into the Clean Channel can be heard. It becomes all the more inconspicuous and disappears completely the louder the Clean Channel is and the less gain is turned up on the overdrive channels.

This phenomenon is normal with the AMP1 Mercury Edition and cannot be avoided due to the layout of the circuit board. Live, this background noise is only perceptible – if at all – with an extreme constellation of clean volume and overdrive gain (see above: clean volume very quiet and overdrive gain and overdrive master turned up full).

A workaround in the studio is to dial back the overdrive gain when using the Clean Channel.

However, there are a few amps where this fade is so loud that it is annoying. The remedy for these devices is to move the CLEAN TONE Custom Control knob on the side of the amp once to the left and once to the right. This significantly reduces the volume of the cross-fading overdrive signal.

More reasons for clipping on the Clean Channel

Here are other reasons why your AMP1's clean channel might be clipping:
Distortion on the Clean Channel‍