The Power Amplifier is a very useful classroom resource that allows students to amplify and listen to a variety of audio sources ranging from microphones and audio devices with a 3.5mm headphone socket to signal generators equipped with 4mm socket outputs. The amplifier is particularly suitable for driving Vibration Generators and Rubens' tubes when a power signal generator is not available. The amplifier has an internal 10W speaker that can be switched offWhen not required. The outputs are overload and short-circuit protected.Output: 3.5Wrms / 4ohm or 2Wrms / 8ohmTotal harmonic distortion: 0.05% (1W / 1kHz)Frequency response: 20Hz to 20kHz (-3dB)Signal-to-noise ratio: 86dB (A weighted)Input sensitivity: 40mV / 150K OhmSupply voltage: 12Vdc