A lamp apparatus includes at least one filament; an amount of amalgam; a heatsink assembly connected to the lamp apparatus; and at least one control circuit comprising a heating element and a temperature measurement element connected to the at least one filament, wherein the control circuit is configured to vary the electrical power delivered to the heating element, thereby controlling an internal temperature of the lamp apparatus relative to a temperature set point. Other aspects, as a method and a computer program product, are described and claimed.