As 3 out of 5 halogen g4 bulbs in a fitting had gone I decided to replace all 5 with new LEDs. Went with Philips as they tend to be more reliable than the no-name Chinese brands. Unfortunately the bulbs are making a buzzing noise which gets progressively worse before starting to flicker badly. Any ideas what could be causing this? Seems off and assume it’s related to the fitting (less than 10 years old). Thanks.