Here the stereo power amplifier based on single IC STK4141II. This stereo amplifier circuit will deliver 25W audio power on each output channel.
Recommended voltage is 27.5V for 8 ohms speaker and 24.5V for 4 ohms speaker while the maximum voltage to supply this circuit should be about 41 VDC. This circuit operated with dual polarity (symmectrical) power supply, so center tap type of transformer should be used. Use minimum 2A transformer for better result.
Heatsink usage on the power IC is a must to prevent overheating and keep the good performance of STK4141II.
Use this STK4141II Datasheet for the circuit reference: