So , I have a lifco 1000 tube amp ( yba-1 clone) that is having a problem. The problem is when raise the 2 inputs volumes at the same time , and then turn the bass or low pots up, it makes a big electric sound like if something was shorting out, it even makes the power tubes glow more as the sound grows bigger... Its not doing it with all the tone stack turned down to zero, when i raise the treble pot no problem, only with the bass and low pots. How can this happens it looks like filament current was going up when turning those pots. I tried changing all pots with no success.... Could this be a faulty cap in the tone stack ? Thank you for helping me .