Try this with your tubes (from a well known tube seller)
Now, what if I heard something? For noise, at normal listening volume at your listening position you will clearly hear hiss, pops, crackles, rumble, whistles, or any combination of the above. For microphonics, at normal listening volume you will clearly hear tapping through the speakers as you tap on the unit. In the case of noise, you may be able to fix it yourself. First, locate which tube is noisy. You may have to substitute one tube at a time and try the unit out until the noise vanishes, indicating the last tube you took out is the one. If you don't have spare tubes, just swap the tubes one at a time from the left channel to the right channel and listen after each tube swap. The noise will follow the noisy tube to the other channel. Take that tube out of your unit and tap it on its side firmly on a table top. Then, hold it upright and tap it firmly with a wooden pencil. This will nearly always knock the offending flake of material out of the grid where it will cause no more noise. Reseat the tube and give it a good 12 to 48 hours of burn in time and the noise should be gone for good. I know it sounds extreme but in at least 85% of noise cases, this resolves the problem. Some audiophiles have said tapping a tube can CAUSE it to become microphonic. I totally disagree. I have tried this trick for 25 years with mostly successful outcomes, and never once has a tube become microphonic after tapping it.