Hi everyone, I just took delivery of a new Pro Junior IV - unfortunately, it has quite a bad hum. This occurs with nothing plugged into the amp and is not affected by the knob settings at all. It fades in as the amp warms up and comes ‘on’ a few seconds after switching it on. Any advice on obvious fixes? I’m an experienced player but not experienced in doing amp tweaks - same old AC15TBX has served me well for almost 20 years so never had cause. I don’t want to be doing too much troubleshooting on a brand new amp - I know some noise can be expected but this is definitely louder than should be acceptable. I hope it’s an easy fix because I love the sound of the thing otherwise. Thanks in advance for any tips.