60 Watt Amplifier Circuit using IC STK4038 II

The 60 watt amplifier circuit that uses the STK4038 II is a powerful audio amplifier that can provide 60 watts of sound to a 4 ohm speaker.

This circuit is perfect for home audio setups, public speaking events and other situations where you need to boost sound.

The STK4038 II is a top notch hybrid integrated circuit made just for audio, featuring low distortion, strong output power and safety measures to prevent overheating.

This article goes into detail about how the circuit works, the math behind it and how to put it together making it easy for beginners to build and understand the amplifier.

Circuit Working:

Parts List:

The audio signal enters the circuit via resistor R1 and coupling capacitor C1.

Capacitor C12 helps eliminate high frequency noise making sure the input signal is clear.

The STK4038 II integrated circuit boosts the input signal.

Inside the IC, there are several stages including differential amplifiers and push pull output stages, which work together to provide the right amount of gain and power.

Resistors R6 and R7 along with capacitors like C6, C7 and C5 create negative feedback and help with frequency compensation.

This keeps the circuit stable and enhances the quality of the audio.

The boosted audio signal is sent to the speaker through a decoupling capacitor C9.

Resistor R2 protects the speaker from too much current, while C9 makes sure that no DC voltage gets to the speaker.

Capacitors C2, C3, C8 and C10 help decouple the positive and negative supply rails which keeps everything running smoothly.

The highest supply voltage that the STK4038 can handle is +/- 57V DC.

Formulas with Calculations:

Formulas with calculations for 60 Watt Amplifier Circuit Using IC STK4038 II is mentioned below:

Voltage Gain:

The voltage gain Av of the amplifier is determined by the feedback network:

Av = R6 / R7

Substituting the values:

Av = 56kΩ / 100Ω = 560

Thus, the amplifier has a gain of 560.

Coupling Capacitor Frequency:

The value of the coupling capacitor C1 is chosen to ensure proper low frequency response:

fc = 1 / (2 * π * R1 * C1)

Substituting R1 = 1k and C1 = 4.7μF:

fc = 1 / (2 * 3.14 * 1000 * 4.7e – 6) = 33.86 Hz

This ensures good bass response.

How to Build:

To build a 60 Watt Amplifier Circuit using IC STK4038 II following are the connections steps to follow:

• Assemble all the circuit parts mentioned the above circuit diagram.
• Connect pin 1 of IC STK4038 II to audio IN through capacitor C1 and resistor R1, connect resistor R3 through pin 1 to GND, and connect capacitor C12 through pin 1 and GND.
• Connect pin 2 of IC STK4038 II through capacitor C2 and resistor R4 in series and GND.
• Connect pin 3 of IC STK4038 II to GND.
• Connect pin 4 of IC STK4038 II to GND through resistor R5.
• Connect pin 5 of IC STK4038 II trough capacitor C3 and GND, connect resistor R7 between pin 5 and capacitor C3, connect capacitor C8 from negative supply of -57V and GND
• Connect pin 7 of IC STK4038 II to pin 10 through capacitor C7.
• Connect pin 9 of IC STK4038 II to pin 10 and pin 12 through capacitors C5 and C6 as shown in circuit diagram.
• Connect pin 12 of IC STK4038 II to negative supply of -57V.
• Connect pin 13 of IC STK4038 II to one end of 4Ω speaker and other end of speaker to GND.
• Connect resistor R6 from pin 13 of IC STK4038 II between pin 4 and capacitor C2.
• Connect capacitor C9 and resistor R2 from pin 13 and GND.
• Connect pin 14 of IC STK4038 II to positive supply of +57V.
• Connect pin 15 of IC STK4038 II through resistor R8 and connect capacitor C10 from positive supply of +57V and GND.
• Connect capacitor C11 from pin 15 of IC STK4038 II and GND.
  

Conclusion:

The 60 watt amplifier circuit that uses the STK4038 II is a great option for boosting audio quality.

It is simple design along with the strong capabilities of the STK4038 II guarantees dependable and clear sound.

If you follow the clear instructions and building steps, you can easily create and enjoy this amplifier in your sound system.

References:

Datasheet STK4038II