A method for assembling a lamp fixture incorporates a ballast and a compact gas discharge lamp into the fixture. A comparator circuit, clamp circuit, and control circuit are assembled into the ballast such that the comparator circuit compares a measured value of a lamp parameter to a threshold value and provides a signal indicative of the comparison; the clamp circuit receives the clamp signal and provides a clamp signal in accordance therewith; and the control circuit, in accordance with the clamp signal, controls the lamp such that the light level of the lamp can be lowered without perceptible flicker.