Hybrid power amplifier circuit,100W-150W using STK-4048

This amplifier series is so special with Hybrid power amplifier circuit that low distortion about 0.003% only.

The heart working of this circuit is the hybrid IC of Sanyo. It is usually found in expensive audio equipment.

The ICs that uses has three wattages to choose the number below.

STK4044XI = 100W
STK4046XI = 120W
STK4048XI = 150W

As following table shows the features of the IC table 1.
IC family STK4044XI-4048XI has developed various models from STK4044II, STK4044V and STK4044X respectively, Until STK4044XI model we use in this circuit.

the datasheet of STK4036XI Series

Table 1 the datasheet of STK4036XI Series

The IC has the internal circuit different due to improved,which external circuit can be used instead of directly.

For this reason, we say that. Be careful before buying it Some may be subjected to such a low quality version of the ICA STK4044II.

compare between STK4036II and STK4036XI
Table 2 compare between STK4036II and STK4036XI

Consider the comparison feature of Table 2, you will know the difference.

In Figure 1 will see that the internal circuit in STK4044XI and STK4048XI that will be have the beginning circuits same together will be different that the output section of STK4048XI will have two output transistors to parallel, allowing for increased wattages up to 150 watts.
the inside ICs circuit
Figure 1 the inside ICs circuit

Thus, at 15 pins of first will be same, but in this circuit have the output and input pins are 3 pins only as Figure 2

The real schematic circuit diagram of this projects

Figure 2 The real schematic circuit diagram of this project

In Figure 3 the PCB layout and components layout which we are designed to be shared by the three numbers as above, if the number STK4044XI released them float the 16-18 pins.

The PCB layout
Figure 3 The PCB layout

The components layout
Figure 4 The components layout

The power supply circuit
Figure 5 The power supply circuit

How it builds

Connect the device to circuit properly, especially the electrolytic capacitors do not reverse polarity is strictly prohibited. Because of the relatively high power circuits used in capacitors may explode easily.

When assembly is complete, connect the power supply voltage to this circuit.

Caution! This project needs to use the speaker protection circuit. Otherwise, your speaker may be damaged.

Parts you will need
IC1(100W): STK4044XI
0.5W 1% Resistors
R1,R5: 1K
R2: 56K
R3: 560Ω
R4: 10K
R2: 100Ω
R8: 56K
R9,R14: 10Ω  1W Resistor
R10: 0.3Ω 5W Resistor
R11,R12,R13: 0.3Ω 5W Resistor
C1: 470pF 50V MKT capacitors
C2: 4.7uF 25V Electrolytic
C4,C17: 100uF 100V Electrolytic capacitors
C5* : 100pF(470pF) 50V MKT capacitors
C7: 0.001uF 50V MKT capacitors
C9* : 3-5pF 50V MKT capacitors
C10: 1uF 50V Electrolytic capacitors
C11: 0.1uF 63V MKT Capacitors
C12,C14: 10uF 100V Electrolytic Capacitors
C13,C15: 1-100 MKT
C16*: 47pF 50V MKT Capacitors
L1: Coil 22T #18AWG Dia.5mm
The device marked with * are used in cases like growth rate decreased from 40 dB to 26 dB.

The power supply
T1___(100W) 5A Sec. 35-0-35
____(120W) 5A Sec. 38-0-38
____(150W) 5A Sec. 42-0-42
D1____Bridge 10A 200V
C1____0.1uF 250V X-cap capacitors
C2____0.01uF 100V MKT capacitors
C5,C6___10000uF 63V electrolytic capacitors

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This Post Has 14 Comments

  1. I am very interested in this circuit (100-150W Super Hybrid Low THD Power amplifiers using STK-4048), I want to know if it is possible to buy a kit and how can I do. I live in Rome and Italy, I do not know where to turn.
    Aldo Rizzo
    [email protected]

  2. I built the stk4048 amplifier on veto board and works very well.

  3. Hi Billy
    Thanks for your feedback.
    I am happy hear you sound. It is power for me keep this jobs.

  4. i hope you could indicate the technical specs of the circuit such as frequency response, distortion ( indicated already ), power supply and others.

  5. I have 320watts Sub-Woofers(8″)-2, 20watts(8″)speakers-2, 50watts(4″)Twitters-2.
    I very much interested to build a home theater. Please suggest which series STK circuit Board use for make a amplifier. please send details in my mail ID ([email protected])
    —– Mahesh Bahadursha

  6. There’s errors in this project. C5 polarity is inverted on PCB layout.Billy you can give me the layout?

  7. Hey guys, any chance i can also get a circuit based on STK432-070.

    I have an Old jvc ux-g68 would really like to use these components already on hand
    Can you help
    email id: [email protected]

  8. Can I use Stk4171 ll ?

  9. Choosing Heatsink for STK4048XI
    Which size of heatsink is recommended for single STK 4048XI and for Stereo can we use one heatsink for both or using separate is better ?
    Waiting for reply

  10. In principle, there is no need to use a large heat sink. But I think it should be used in a large size first. IC has a high price And it’s very important

  11. Que medida tiene ese pcb

    1. Thank you that you are interested this circuit. I don’t have service to sell the PCB.

  12. Thank you very much your excellent guide about the circuit. I will try to build it.

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