A brzzzzz noise from transformer, is it normal?

Hello audiophiles,

I need help on this brzzzz noise from my Classe CA201 amp, properly from the transformer. I could hear its sound like a small power plant when I put my ears close by (even I disconected all sources, so there is no signal feed to it), it is quite bother a bit, especially on a quiet day when music stop. Is this noise normal for a big amp or any amp? The good thing is the noise does not go to or sound on the speakers. Or is it because of the dirty power I feed it. I did try to turn off everything such as lights, air conditioning etc... It sounds quieter a bit when the amp heat up.

If you have the same problem, or know what this noise come in from or how to fix it, please post your help. I don't want to send the amp to manufacture if it is really a problem. This amp is 70lbs piece of rock not a pleasure thing to ship around.

Thanks all for your help.
Many transformers will buzz slightly, and you might hear it with your ear next to them. I wouldn't worry about this. If the buzz becomes audible through the speakers, or is loud enough to hear from a couple feet away from the equipment, then the plates are de-laminating, and the tranny would need replacing.
There are other reasons a transformer will buzz besides being defective. The mounting bolts may be loose. It may be buzzing because it is getting fed noise on the AC line from a dimmer. The dimmer on the light in my stove hood will cause a power conditioner in my basement to buzz.
The CA201 uses a big toroid for it's power tranny, - it shouldnt' buzz at all. I have a CA200 which is basically the same amp - no buzzing, humming. The tranny is encased in a machined aluminum cylinder so even less reason it should be making noise. Something is definitely up. Caps should need checking too, could be one is bad. This amp should be dead silent when nothing is playing through it.

Toriodal transformers are infamous for buzzing when fed dirty AC.