I have been working on a solid state amp, it's now in working condition but there is a loud hum (AC)? It is always present on both channels and is not altered with the volume control. there is about 180mv of ac on each channel dc is only - 1.8 mv . I have attached a couple of photos of the scope connected to the speaker teminal . one of just the AC ? wave and the second is with a 1khz tone on top of it. I am thinking it is a capacitor problem any idea's? many thanks.