Hi, Just got used Tubepath 10.1. At first it worked fine, but after changing the tubes it suddenly started to rattle. Soon the rattle changed to a very low hum. Amp also lost its power. I tested the tubes and tried another ones. I opened the amp and noticed that the grey cable (gain signal or gain hot) going from the gain potentiometer to the first preamp tube gives a popping sound (in very similar frequency that the continuous hum has) when I move or tap it. It's like lower freq sound of tapping a microphonic tube. Soldering looked fine and there was not any visible short circuits (<- Is that a real word?) Does anyone have any experiences on this? Or any idea how to fix it? I hope you understand what I've tried to say. I'm finnish and it's kind of hard to produce this tech talk.