Just changed the power tubes in my V.Seems to be working fine but 1 tube(far left when looking at the back of the amp) is glowing less then the other 3.Its still glowing but not as much as the others or the rectifier tube.Maybe its always been like this but im just very aware of it since i just swapped them out.Is this common or is there a reason for it.Mesa tubes,matched pairs,in the right slots etc.Cheers