Buzzing sound from mirror light

Lex Luthor

just fitted new mirror light in bathroom. It has 2 lights connected what look like 12V halogen bulbs. Transformer at the back of the mirror.
After about 1 min a buzzing noise can be heard from the back of the mirror.
Is this normal with these transformers once they heat up?

Stoner

Buzzing is usually due to iffy traffos and is not normal. Is the traffo rated to supply the sum of the lamps watts? , you could always put smaller lamps in, the traffo could also be touching of something and a little pyhsical adjustment may sort it out. are you dimming the lights, if so the traffo might not be suitable for dimming most are but you still see the odd china special arround the place.
I'd bring it back if the physical adjsutment did not work,
if you have it dimmed then change the dimmer switch to a normal switch, I know from reading here that you have most of these skills

Lex Luthor

No dimmer.....it's a batroom wall mirror with a trafo mounted to the back. direct connection into the mains to the trafo.

I bought the mirror and brochure showed it having 2 lights. Got the 2 lights but the trafo only had connectors for one light, so I had to splice into the wiring and connect in the 2nd light. Thinking the trafo is not rated for the 2. I might plug out one light and see if the buzzing stops.
Cheers