An RF amplifier assembly employing a finned heat sink and a heat pipe enhanced aluminum pallet is disclosed. The hybrid heat pipe enhanced aluminum pallet reduces the spreading thermal conduction resistance associated with the conduction of localized energy from RF amplifier devices when compared to a copper pallet. The localized energy concentration of RF amplifier devices is spread along the length of the heat pipe increasing the overall efficiency of the heat sink coupled to the pallet and accommodating non-uniform heat loading. This reduces the junction temperature of the devices, which leads to higher mean time before failure and higher output levels. The pipes are formed and embedded into the pallet so as to pass under different areas of interest and extend to the under-utilized regions.