DerbyBorn used his keyboard to write :
I used to have a separate doorbell transformer. During some kitchen work
the electrician fitted a new transformer inside the consumer unit. I can
now hear a (50Hz)buzz in the bedroom above.

At the moment I am not fit enough to do any streching to try relocating it
or trying to mechanically isolate it. I am wondering it an electronic
voltage reduction device is available that could be smaller and not liable
to vibrate.
The door bell - is a load buzzer.

Most everyone moved over to modern wireless versions long ago, but best
to get a good one Freidland EVO are a good and reliable one.

Just isolate the input to the transformer, likely its core will have
worked loose.

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Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk