Plinius 9200 - transformer buzz


I have a problem with my Plinius 9200. Buzz comming from it's transformer is occasionally very loud, annoying and distracting especially during low passages. It's not constant, for most of the time the transformer is silent. Have you experienced that with your Plinius? What could be the possibly reason and how to solve the problem. I've written to the manufacturer, to Plinius Audio but haven't received any answer.
Power supply 230V (Europe), dedicated PC (I have tried a couple of them on the amp).

Thanks
jkuc

Showing 1 response by twoleftears

Here's a quote from Roger A. Modjeski--who I figure should know a thing or two--posting on AudioCircle.

"One thing to keep in mind about toroids. If there is any DC on your power line the transformer will audibly buzz and the magnetizing current will go up. This is because they have no air gap. EI transformers have an unintentional air gap of about .001 inches. That's all it takes to keep a transformer happy with a volt or two on the line."