Tube noise when gain is increased, tube issue?

Buzzing or humming is usually from the transformer and can excite a noisy tube. If you don't need the extra gain, switch back to low gain, it is always quieter.

Russ69, FWIW I think OP was referring to using his attenuator to adjust gain. At least that is how I read it.

Russ69, FWIW I think OP was referring to using his attenuator to adjust gain. At least that is how I read it.

Oh, OK. I guess he is hearing tube noise when he turns up the volume and nothing is playing? Lots of questions in that case. Is this something new? Do you hear the noise when playing music? What preamp?

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. 

microphonic tube. Switch tubes and see what happens.

If it is only one tube try another.