The amplifier introduced in this article takes Sony's C1891A as the core and LM1875 as the main power amplifier. It has the characteristics of low price, simple and easy production, and obvious effects. It is very suitable for beginners to make their own.
Circuit principle:
1. Surround sound processing part
C1891A is a home theater 4D surround sound processing circuit launched by Sony Corporation of Japan. This circuit uses a matrix phase-shifting surround sound amplifier. Three sound field effect modes including concert hall, movie theater, and analog stereo are also specially established. The specific application circuit is shown in Figure 10-20. The brief introduction of each function pin is as follows: pins 2 and 3 are left and right channel outputs; pins 8 and 9 are left and right channel inputs, and pin 10 is surround output; 11. Pin 12 is the state selection pin (connecting + 5V level can change the sound field mode), using the integrated circuit CD4017 to make a one-button state selection switch, with color light indication, and the effect is good; Pin 13 is the effect adjustment terminal.
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