brain strain
Lamp resistance is low when cold. This will cause an initial current inrush causing the noise (my theory).
Simple to verify this low resistance issue with a meter, a 14 volt source and TS lamps.
1 Measure the total cold resistance of the lamps.
2 calculate the watts @ 14 volts using OHMS law.
3 Then power the lamps at 14 volts and measure the current.
4 Calculate the watts using EI=W.
5 Then compare the TWO results.
vicrod
