This post explains for the amplifier.
The Part Number is STK403-130.
The function of this semiconductor is AF power amplifier.
The package is SIP 15 Pin Type
Manufacturer: Sanken Electric
Preview images :
This is 2 channels AF power amplifier.
The STK403-130 is a power amplifier integrated circuit (IC) manufactured by Sanken. It is used in audio systems and designed to drive speaker loads. It features a high output power and low distortion, making it suitable for use in a variety of audio applications.
1. 100 W audio use
Other data sheets are available within the file:
STK-403130, STK-403-130, STK403130