The op amp functions are from left to right:
(1). Single-ended transfer balance of the subwoofer (single-ended to differential).
(2). Signal amplification and frequency compensation of the subwoofer.
(3). Left channel signal amplification and buffering
(4). Right channel signal amplification and buffering.
4 LM1875 power amplifier IC functions:
(1). The two left sides are connected to form a differential amplifier to work in BTL mode. It is responsible for subwoofer amplification.
(2). The two on the right are responsible for the power amplification of the left and right channels.
The terminals are from left to right:
(1). Input the left and right channel audio signals, and connect to the audio equipment such as computer.MP3.MP4.
(2). Subwoofer output (OUT-SB), effective output 60W, connected to 40-100W subwoofer. 8 ohms and above is appropriate, otherwise the fever is serious.
(3). Left channel output (OUT-L), connected to the left speaker, effective output 20W, 20-50W speaker, impedance is 4-8 Euro.
(4). Right channel output (OUT-R), connected to the right speaker, effective output 20W, 20-50W speaker, impedance is 4-8 Euro.
PCB size: length 170m* width 90mm, with radiator size: length 170mm* width 135mm* height 50mm