Jea48, not so in my experience
05-15-09: Detlof
Quote from Link:
7. Noise
Transformers make noise. This is not only the electrical noise that is created by the nasty current waveform through the windings, diodes and into the filter capacitors, but actual audible noise. One source is winding vibration, due to the wire moving because of the magnetic field and the current flowing through the conductors. This is to be avoided at all costs, since constant vibration will eventually wear away the insulation, the windings will short circuit, and the transformer is ruined. Fortunately, this is rather unusual, but it can (and does) happen on occasion.
Most of the noise is from the laminations or other core material, which contract when subjected to an intense magnetic field. This is called magnetostriction, and happens to a greater or lesser degree with all magnetic materials. A stethoscope will verify the source of the noise, and there is little or nothing that will stop it. A resilient mounting will stop most of the noise from being acoustically amplified by the chassis, and generally the noise will be worse at no load. In some cases, a transformer may have been designed for 60Hz, but is used at 50Hz. In this case, the flux density will probably exceed the maximum allowable for the core, and the transformer will get much hotter than it should, and will almost certainly be a lot noisier as well. Toroidal transformers will generally be much quieter than EI laminated (i.e. conventional) types.
Most(all?) transformers designed specifically for 60Hz will eventually fail with 50Hz mains, due to overheating. The reverse is not true, and 50Hz transformers can be operated quite safely on 60Hz.
http://sound.westhost.com/xfmr.htm#7-noise
