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 projects

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 to 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.

The parts you will need
R1,R5___________1K___0.5W 1% Resistors
R2________100 ohms____”__________”___
R9,R14_______10 ohms __1W________”___
R10__________0.3 ohms__5W________”___
R11,R12,R13__0.3 ohms__5W________”___
C1__________470pF 50V MKT capacitors
C2__________4.7uF 25V Electrolytic capacitors
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


  1. Aldo Rizzo May 6, 2015
  2. Billy July 8, 2015
  3. momename July 8, 2015
  4. harold sy September 7, 2015
  5. Mahesh Bahadursha November 13, 2015
  6. Kim Lee Baw November 25, 2015
  7. Onesimus Tozeyana May 11, 2016
  8. akash pillai (akku) November 16, 2016

Add a Comment

Your email address will not be published. Required fields are marked *