50w MOSFET amplifier circuit OCL using K1058 + J162

If you like to listen to nice music at your home. And you like to build electronic projects. You may like this. It is the 50w MOSFET amplifier circuit using 2SK1058 & 2SJ162.

Even if you’ve built this 50W Main Amplifier using transistor and IC.

But this circuit is better. The power of sound in low frequency is great. Also, It is easy to build, and very inexpensive.

Also, use Power Supply +35V -35V at 5A(stereo). Power MOSFET 2SK1058 & 2SJ162 must be mounted on enough heatsink.

We can directly connect it to CD players, tuners and MP3 player.

If you want a good amplifier, at affordable prices, for you to enjoy at home.

I recommend this circuit. Which has excellent sound quality. It is not lost other expensive sound system.

See spec below.

Features of the circuit

• Power output at 1kHz
• Load 8 ohm 50W
• Load 4 ohm 88W
• Power bandwidth +/- 1dB 20-50,000Hz
• Frequency response +/- 1dB 20-50,000Hz
• THD 20Hz-20kHz UP to rate power 0.05%
• Slew rate 20V/ microSec.
• Damping factor better than 50
• Signal to noise ratio 88dB.
• Input voltage for maximum 100mV.

How MOSFET amplifier circuit works

See the circuit below. We will see that it is similar to a general MOSFET audio amplifier. Except for the output power MOSFET.

Instead, we use 2SJ49 and 2SK134. Which are more old, expensive and not necessary.

We use dual output Power MOSFET 2SJ162 and 2SK1058. Cheap much more. And other features, not less than any.

See Circuit diagram of 50 watts OCL Power Amplifier using 2SK1058 + 2SJ162

Also, the results from this circuit, it is the high-frequency response to better than output Power MOSFET J49/K134.

The operation of the circuit

The input signal is entered to C1 pass through a low pass filter circuit, R2, C2.

Then, to the differential input circuit, Q1(MPSA93), Q2(MPSA93) to Q4(MPSA43), Q5(MPSA43).

They act to amplifier an input signal to the Input signal to be strong enough to drive the gate of the output MOSFET. (Q8, Q9).

Then, the diodes, D1, D2, D3, D4, and D5. They are a protection circuit to prevent the too higher voltage to the gate of the MOSFET.

It may cause damage to the power MOSFET.

Recommended: High MOSFET Power Amplifier

Next, both transistors Q6 (BC546) and Q7(BC556) control the voltage that power to the driver section.

To not change follow the swing of the power supply. While we turn on the power to high.

This will also prevent noise that feedback to from the power supply wires. So, to reduce the noise of the circuit as well.

The power supply

This circuit requires enough power supply circuit. We use the 35V 5A Dual power supply circuit below. It is easy and uses a few parts.

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How to build

This circuit is very easy to make. Because it is designed in the PCB module. To reduce oscillation from the wiring at legs of MOSFETs is too long.

See the PCB layout below

And see the component layout below

Therefore, every piece of equipment. Including the power MOSFET and the heatsink. They are designed to install on the PCB. as shown in figure above.

The Shopping lists

0.5W Resistors, tolerance: 1%
R1: 100K
R2: 2.2K
R3: 7.5K
R4, R5, R7, R8: 5.1K
R6, R13: 150 ohms
R9: 100 ohms
R10: 15K
R11: 270 ohms
R12: 330 ohms
R14, R15: 120K
R16, R19: 4.7K
R17, R18: 560 ohms
R20, R21: 10 ohms 1 watts

Electrolytic Capacitors
C1: 2.2µF 50V
C3: 220µF 25V
C8, C9: 47uF 50V

Metalized polypropylene capacitors or Ceramic
C2: 100pF 50V
C4: 50pF 50V
C5: 0.1uF 63V
C6, C7: 68pF 50V
C10, C11: 0.22uF 50V
C12, C13, C14: 0.047uF 50V

Semiconductors
D1, D2, D3: 1N4148, 75V 150mA Diodes
D4, D5: 15V 0.5W Zener Diodes
Q1, Q2, Q3: MPSA93
Q4, Q5: MPSA43
Q6: BC546, 60V 0.1A, NPN TO-92 Transistor
Q7: BC556, 60V 0.1A, PNP TO-92 Transistor
Q8: 2SK1058
Q9: 2SJ162

In creating, So just connects devices to form correctly. And Be careful soldering point to the closest. No Short circuit between that soldering points.

Check the output MOSFET that inserts the mica insulation. Is good enough or not?

Using Ohmmeter measurement. To make sure not short circuit or Short to the heat sink.

When testing all done, until sure is good to successfully. So, the trial connected the voltage of the power supply to the circuit to work right away.

MOSFET Amplifier Circuit using 2SK134 & 2SJ49

This has been the first simple MOSFET amplifier circuit for me. It is a quite complete circuit. As a 60 watts power amplifier, this is sufficient for normal use in my home. The circuit may be outdated.

It has several advantages. Try to read, then you will like it. The most important is the durability of the amplifier.

The MOSFET power amplifier is the answer to the above problems. The two main features.

1. No problem with the Thermal Breakdown as like a normal transistors circuit. It can be used with all load types, Without fear of damage, the output power the only reduced.
2. Do not need the protection as a plain transistor circuit so to work continuously.

Do you interest in it? Let’s learn it in this circuit below.

How this circuit works

See in the circuit.

The signal from a tone control circuit is entered to pass the RF filter circuit. They consisting of C3 and R2 into the base of the transistor (Q1). It is connected with Q2 as the Differential amplifier circuit.

We use the low noise transistors, BC556 PNP type. Then, the output from Q1, Q2 will be fed to the differential amplifier circuit, series second. They consisting of the Q4, Q5 (2SC1775).

The transistor Q3 and D1 act as the active collector load, to get the output signal in a push-pull model. To drive the gate of the transistor output Q8(2SK143) and Q9(2SJ49).

And at the gate of both power MOSFETs, it has diodes D2-D5 attach to protects the overdrive.

Because MOSFET has distortion very low. So the negative feedback circuit has a signal is 45 dB only. It is fed from the output pass to R8, R8, C4 comes to the base pin of the Q8, Q9.

Using low feedback as above. It will help to the distortion at the low overload point is lower than a normal transistor circuit that used a feedback up to 60 dB.

Then, the wire is connected from the power MOSFET to the input section circuit. We connect to pass a decoupling electronic circuit, to help of low distortion is all every value power output. And the signal-noise ratio is better, too.

Because the MOSFET transistor circuit has a future of the Negative Temperature to the coefficient. Thus, this circuit so does not need to set an idle current, the current circuit is between only 50 mA.

Read other:

• Make Simple 555 Inverter circuit using MOSFET
• Simple time Delay Circuit using MOSFET

MOSFET Amplifier power supply

The characteristics of the power supply as shown in the figure below.

You should check the accuracy and neatness, the Soldering point close to the point. Then, connect the power MOSFET. The wiring should be used a square of 0.5 mm at a minimum, as short as possible.

And then to the power supply circuit. Then connect to the loudspeaker. And the input signal from the tone control circuit was also used.

The shopping list

0.5W Resistors, tolerance: 1%
R1: 39K
R3: 100K
R4: 2.2K
R2, R5: 2.7K
R6: 150 ohms
R7, R10: 15K
R8: 12K
R11, R12: 100 ohms
R13: 330 ohms
R9: 220 ohms
R14, R16: 120K
R15, R17: 4.7K
R18, R19: 560 ohms
R20, R21: 10 ohms 1watts

Electrolytic Capacitors
C1: 2.2uF 50V
C4: 220uF 25V
C6, C8: 47uF 50V

MKT (Metallized Polyester Film) or MKP (metalized polypropylene Capacitors
C2: 100pF 63V
C3: 10pF 63V
C5, C13, C14: 0.1uF 63V
C12: 0.047uF 100V
C10, C11: 68pF 63V

Semiconductors and others
Q1, Q2, Q5, Q7: BC556, 60V 0.1A, PNP TO-92 Transistor
Q3, Q4: 2SC1775
Q6: BC546, 60V 0.1A, PNP TO-92 Transistor
Q8: 2SK134 *read text
Q9: 2SJ49 *read text
D1, D2, D3: 1N4148, 75V 150mA Diodes
L1: 18 AWG on 20T DIA. 5mm.

Note:

Now you may be a problem in creating this project. Because buying power MOSFET 2SK134 +2SJ49 is very difficult.

Or use others instead of 2SK135+2SJ50 is cheaper than the same shape. Or use this number instead of IRFP240 + IRFP9240 different shapes(Plastic body).

I do not know the quality of the sound. But friends said the sound is good and cheap as well.

Or other friends recommend this number: BUZ901 + BUZ906.
It will available the same.

 

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