A 24 Watt Class A Amplifier made from discrete semiconductors, built and tested by Marc Klynhans from South Africa.
The circuit was designed as Class A amplifier that would provide 24 Watts of power.The circuit operates over the whole of the input cycle such that the output signal is an exact replica of the input with no clipping.
The P3A amplifier has proven extremely popular, and the DoZ continues to provide enthusiasts with a simple, reliable and easy to build Class-A amplifier.
There are many instances where a simple and reliable power amplifier is needed - rear and centre channel speakers for surround-sound, beefing up the PC speakers, etc. This project is based almost directly on the typical application circuit in the LM3876 National Semiconductor specification sheet.
It can provide much more simply by increasing the power supply voltage. The available output power is limited by the power supply. Up to 70 watts output has been achieved with this topology.
A single-ended Class-A amplifier is essentially one where there is only one active driven output device. The passive load may be a resistor, an inductor (or transformer) or - as in this amplifier - a current sink. The current sink offers the highest linearity for the lowest cost, so is the ideal choice.
This amplifier uses LM1875 chip from National and handful of other components. Only one channel is shown, you can build two similar for a stereo version.
AN-211 Analog Devices Application Notes.
This application note quantifies each of these important parameters and provides supporting empirical data acquired using the TC4864 in the Bridge Tied Load (BTL) topology and the Single-Ended Capacitively Coupled Load (SECCL) topology.
Notes: Can be directly connected to CD players, tuners and tape recorders. Simply add a 10K Log.