This audio Power amplifier circuit consists of several transistors are arranged in such a way so as to form a solid audio amplifier circuit and qualified. This amplifier uses four transistors, each of which has its own function.
Audio Power amplifier circuit can generate power of 90 watts at 4 ohm loudspeaker load. One of the advantages of this circuit is fairly simple construction and can be built at low cost.
From the pictures look transistor level end using 2N3055 that serves as a main amplifier (Power). Therefore, the fourth transistor will heat when operating, so it takes a heatsink enough to cope with the heat at level end of the transistor.
Transistor 2N3904 and 2N3906 serve as the main driver of the amplifier, driver amplifier which is built symmetrically. In order for the strengthening of the audio power amplifier is working perfectly, it is advisable to add a front amplifier circuit between the signal source and power amplifier.
This audio Power amplifier circuit includes an OTL Amplifier (Output Transformer Less) classified, because circuit That using The Elco capacitor on the output. This capacitor function so that DC voltage is not entered to the loudspeaker and AC audio signals only are to be issued.
Amplifier circuit that looks like in the picture, it takes a symmetrical voltage +/- 40Vdc with current 1.5A. So if you’re going to build a stereo amplifier, then the current needed for this amplifier circuit is working optimally is 3A.