Relatively easy to build up to 30 watt OTL amplifier is packed into this project.
If you like to listen to music a comfortably ears. Want to create a your power amplifier projects with yourself. This project will direct your heart for sure. By the power dissipation of 20 watts at 8 ohm or 30 watts at load 4 ohm. And easily without any adjustments and Cheap because We use the three tiger army.. Read more ….
The working principle.
As shown figure the circuit, you know 3 soldier that from one IC-TDA2030 and two transistors (TIP41,TIP42 or 2SC1061,2SA761 or BD908,BD907) for helping to extend the signal up there. Part other equipment is useful Likewise. However will explain it to read as follows.
When we enter the power supply and sound signals into this circuit. The capacitor C1 will prevent DC voltage through it. Therefore, the sound signals is at pin 1 of IC1 easily. And This circuit use a single power supply that has two terminals are positive and Ground(negative), So must be connected two resistor R1-56K, R2-56K and C2-47uF to divide the voltage by half. The R3-56K is the result matches the input IC1. ??Gain of IC1 in this circuit is set as High to 14 time. By setting this circuit to the non inverting amplifier circuit or not inverting there.
Figure 1. The OTL amplifier using TDA2030 and transistors.
The sound signal output is amplified to pin 4 of IC1 And to boost (increase) to increase with Q1 (TIP41) and Q2 (TIP42). The Q1 which is executing by R6. And The Q2 which is executing by R7. The Q1 and Q2 will start work when the many current flow pass to R6 and R7 so has the voltage drop across them exceeds 0.6V which be bias voltage to Q1 and Q2 there.
The sound signal is amplify from Q1 and Q2 then output to a loud speaker by pass away C8-2,200uF and this circuit can protect the loss of high frequency that output to the loud speaker by R8 and C7.
The D1 and D2 are used to prevent Return the voltage from the speaker not to interfere with the IC1, Q1 and Q2. If none of these two diodes may may be damage the device,including money in your pocket separately. The C7 and C8 is a filter to smooth the power again before it is provided to the circuit there.
How to build and setting
Familiar with the project is to making a PCB (printed circuit boards) and buying equipment.
For PCB according to Figure 2. The equipment is a device from the list below.
When you has the PCB with a the correct pattern, Next, bring devices to soldered onto the PCB as shown in Figure 3 do.
Soldering equipment onto PCB, should soldering of the device at the low end to high end, will be a beautiful view. Make sure the device is a terminal before soldering. This project uses IC1, Q1 and Q2 should use the big size heat sink to install them with together as shown in figure 2.
R1,R2,R3_____________________56K 1/4W Resistor +- 5%
R4______________________________3.3K 1/4W Resistor +- 5%
R5______________________________30K 1/4W Resistor +- 5%
R6,R7_________________________1.5 ohm 1/2W Resistor +- 5%
R8_________________________1 ohm 1/2W Resistor +- 5%
C1,C3,C6,C7__________0.22uF 63V__ Polyester Capacitor
C2________________________47uF 25V Electrolytic Capacitors
C4________________________10uF 25V Electrolytic Capacitors
C5,C8___________________2,200uF 50V Electrolytic Capacitors
D1-D2 _______1N4001 or 1N4002
Q1___________PNP transistor 2SA671 or TIP42 or TIP32 or BD908
Q2___________NPN Transistor 2SC1061 or TIP41 or TIP31 or BD907
Sheets of mica, Cooling pad (Heat sink)
How be used
First need to find the power supply size 24 volt to 30 volt 1 amp, The audio source as the tuner, cassette or a CD player, Finally, a 20-watt 8-ohm the loudspeakers. Then they are connected together. For those who want to listen in stereo, you need to build up the two machines. And need to change the power supply is 2 Amps. It can be used. After this, you will hear the for crystal clear sound from the sound that you created yourself.