This part is a kind of semiconductor called STK4141V.

Function of this product has AF Power Amplifier (Split Power Supply) (25W + 25W min / THD = 0.08%).

Manufacturers : Sanyo

Image and pinout :

Some of the text within the PDF file :

Ordering number: EN 1649C Thick Film Hybrid IC STK4141V AF Power Amplifier (Split Power Supply) (25W + 25W min, THD = 0.08%) Features • The STK4102II series (THD=0.4%), STK4201V series (THD=0.08%) and STK4141X series (THD=0.02%) are pin-compatible. Once the PCB pattern is designed, you can easily satisfy the repuirements for new sets simply by changing the IC. • Built-in muting circuit to cut off various kinds of pop noise. • Greatly reduced heat sink due to substrate temperature 125°C guaranteed. • Current mirror circuit application reduces distortion to 0.08%. Package Dimensions unit: mm 4040 [STK4141V] Specifications Maximum Ratings at Ta = 25°C Parameter Maximum supply voltage Thermal resistance Junction temperature Operating substrate temperature Storage temperature A [ ... ]

STK4141V PDF Datasheet Download