I have a pair of monoblock amps and one of them had a slight buzz that eminated from a transformer. The buzz was related to a quality control issue with the epoxy inside the transformer in a small batch of transformers they had received right around the time my amps were built. If the transformer didn't develop a buzz within a couple of weeks, I was told it never would. The other amp was perfectly silent, by the way.
Based on my experience, I would ask your shop to return the amp to the manufacturer diagnosis and replacement of the transformer if necessary.
I have had my amps for over a year and both remain silent.
Based on my experience, I would ask your shop to return the amp to the manufacturer diagnosis and replacement of the transformer if necessary.
I have had my amps for over a year and both remain silent.