Homemade multi-sound effects sound system

The whole circuit is divided into two parts: the first part uses the four-channel surround sound processing chip μPC1892 produced by Japan NEC Corporation (see the figure above), which has amplifiers, low-pass filters, mode control, phase shift, effect processing, compensation absorption, tone, volume and balance circuits. The (25) and (26) pins of the chip are the input terminals of the left and right channel signals respectively. After amplification by the internal circuit, the signals are divided into four channels and output from the (9), (12) to (14) pins respectively. Through the four-channel power amplifier of the second part (see Figure 2), a wonderful four-dimensional surround sound effect can be produced.

The chip also presets three sound field effects: concert hall, cinema and simulated stereo. The sound field effect switching is controlled by the level of the chip (7) and (8) pins, as shown in the following table. In use, it can be selected through S1 and S2. Potentiometer RP1 is for music effect control, RP2 is for output level control, RP3 is for front left and right channel volume control, RP4 is for rear surround sound volume control, RP5 is for bass control, and RP6 is for treble control.

Effect mode pin number

⑦ foot ⑧ foot

Off (no effect) Low level Low level

Concert Hall Effect High Level Low Level

Cinema Effect Low Level High Level

Analog Stereo Effect High Level High Level

The second part shown in the figure below consists of the D-200 and 275 series amplifier modules with few peripheral components. The maximum undistorted output power of the D-200 is 200W, the rated undistorted output power is 100W, and the operating voltage range is 55±5V. The power supply voltage of the 275 module is ±15V～±32V, and the maximum operating voltage does not exceed ±34V.