There are four types of Power Amplifier units in the Praesideo product range. These differ in the number of amplifier channels per frame- one, two, four, or eight. The overall power rating is 500 watts for all of the amplifiers. The Power Amplifiers can be set to 100 V, 70 V and 50 V output tappings. They have short-to-ground and short-circuit detection functions, and can generate their own pilot tone for supervision purposes.