Originally Posted by
RothwellAudio
Ah, I see. Yes, phonostage valves are sensitive to mechanical vibration. A better solution than valve dampers is to have the valve bases (or the PCB which they're on) soft coupled to the chassis rather than in hard contact.
Soft coupling the transformers is also a possibility, but they have to be secured well enough to be safe, of course.
If the chassis is steel it's possible that magnetic induction is causing the chassis to vibrate. A spacer between the transformer and the chassis would help with that.