Vacuum tubes can carry out a wide range of tasks similar to integrated circuits. Unlike integrated circuits, tubes have many disadvantages such as the fact that they take up a large amount of space, have shorter life spans and are less energy efficient. Tubes can control the flow of current in almost any way. They can serve as simple diodes or complex signal amplifiers. Despite the fact that they are obsolete there are qualities of tubes that some audiophiles prefer over digital alternatives when the tubes are used as audio amplifiers. Each tube produces light and heat similar to incandescent lamps because the inner part of the tube is composed of small filaments connected in different fashions to control current in different ways.