I always have an extra set of tubes around. If there is a strange behavior… I swap out the tubes to see if it ends. It usually does… then I swap the old tubes back in one by one, until the problem comes back.
Tube noise when gain is increased, tube issue?
Adjusting gain on my preamp improves the sound vibrancy who makes it sound better. But when I turn it higher the tubes tend to make a buzzing/humming noise which goes away when I turn it back.
Is this a tube problem or a gain problem. It's nice to maximize the gain setting before distortion occurs.