This is a design circuit for amplifier was designed in order to fill the gap in the 3-10 Watts power output range of the audio amplifiers available on RED Free Circuit Designs. Therefore a simple, very low parts-count amplifier, was designed on the same guidelines of the successful 45 Watt Class B Amplifier, but using the excellent NE5534 IC instead of a discrete component op-amp to drive the output "dumper" transistors. This is the figure of the circuit;
Due to the maximum operating voltage restrictions of the chip, the output power cannot exceed 7.5 Watts into 8 Ohm loads, but the Total Harmonic Distortion figures are astonishingly low, much lower than comparable audio amplifiers using a single IC audio amp. Also due to the internal current limiting of the NE5534, the output power into 4 Ohm loads will be no more than 8 Watts. Other interesting features of this amplifier are the absence of any kind of setup and the possibility to be driven directly by the audio source (CD player, Tuner, iPod etc.).
In any case, a simple, optional preamplifier circuit is provided, allowing to cope with very low output audio sources and featuring a single-knob bass and treble Tone Control.
