On Sun, 2 Dec 2012 22:00:45 -0000, "Brian Gaff"
wrote:

Well I have a double tube fitting and one side always did hum, presumably
from something loose in the choke. Are you saying it only hums on the
electronic starter, it could be that the clicking etc masks it.

The electronic starter works in other light fittings without humming,
but when I use it in this one, when I switch the lamp on I get a hum
and darkness for half a second and then the light comes on and the hum
stops. You could be right, it could be that the fitting hums with any
starter but the noise from blinking with the "traditional" starter
masks it.