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100 Watt Single OP-AMP Amplifier with Speaker Protector.


1. 1×BD140 Transistor.
2. 1×BD139 Transistor.
3. 1×2SC4793/ TIP41C Transistor.
4. 1×2SA1837/ TIP42C Transistor.
5. 1×2SC5200 Transistor.
6. 1×2SA1943 Transistor.
7. 2×2N5551 Transistor.
8. ×2N5401 Transistor.
9. 6×3.3KΩ resistor 1/4W.
10. 3×330Ω resistor 1/4W.
11. 4×4.7Ω resistor 1/4W.
12. 1×10Ω resistor 1/4W.
13. 2×150Ω resistor 1/4W.
14. 9×10KΩ resistor 1/4W.
15. 1×47KΩ resistor 1/4W.
16. 2×2.2KΩ resistor 1W.
17. 2×IN4744 (15V 1W) Zener Diode.
18. 1×IN4742 (12V 1W) Zener Diode.
19. 1×IN4747 (20V 1W) Zener Diode.
20. 1×1uF capacitor 50V.
21. 5×100uF capacitor 50V.
22. 2×4700uF capacitor 50V.
23. 3×220pF (221) capacitor 50/100V.
24. 4×0.1uF (104) capacitor 50/100V.
25. 1×0.15uF (154) capacitor 50/100V.
26. 1×100K Single turn potentiometer.
27. 1×2 pin 2.54 mm socket.
28. 1× TL072/ NE5532/ 4558D IC.
29. 1×2 pin 2.54 mm socket.
30. 1×GBU1508 Bridge Rectifier.
31. 1×Relay 12VDC.
32. 1×2 Pin Screw Terminal.
33. 1×3 Pin Screw Terminal.

License:- ©Technical Mriganka. You can't use this PCB Layout and Gerber File for commercial purpose. You can use this PCB layout and Gerber file only for Educational and DIY projects.

PCB Layout & Schematic:-

How I make this Amplifier

Hello guys, in this post I make a 100 Watts mono amplifier. This is a class AB mono amplifier. Which can deliver up to 130 Watts RMS output at 4Ω ±30V, Test frequency 1khz. And 70 Watts RMS output at 8Ω ±35V, Test frequency 1khz. For this amplifier I used 1 pair of 2SC5200 and 2SA1943 Transistor. This amplifier have have in-built Speaker protection. So if for some reason the transistor will burn, this built-in speaker protection circuit will protect the Speaker from high DC voltage.


For designing my PCB, I used EasyEda online software. Then I export the Gerber file (which you can download). And then I go to for manufacturing my PCB. PCBWay are the largest PCB manufacturer in China. They offer Standard PCB, Advanced PCB, Rigid-Flex PCB, SMD-Stencil and PCB Assembly Service. Here you get, 100x100mm 2 Layer PCB only at $5, And processing time within 24 hour. And they distribute, worldwide. The more you order, the less price you have to pay.

You just need to upload the Gerber File, and select the quantity, color, silkscreen, thickness etc. Then select your country, and shipping method. And then Pay.

After 7 days I have received my PCB. You can see the PCB quality, it's awesome. I have ordered Yellow color PCB. But you can choose your PCB color. PCBWay provide total 9 color solder mask - Green, Blue, Red, Purple, Black, White, Yellow, Matte Black and Matte Green. On PCBWay you can get 100x100mm 2 Layer PCB only at $5. Maximum size PCB you can get 500x1100mm. And maximum Layer is up to 14 Layers. And If you order PCB first time at PCBWay, then you get a $5 discount coupon. So upload your Gerber today and get best quality PCB.

How to Test this Amplifier

Series light test:- After complete this board don't forget to series light test. When you will on this amplifier via series light, it glow for some time (1 - 2 sec). Then series light will turned off fully. If the series light will fully turned off, then check the voltages.

Check Voltages:- Biasing = 0.5-0.7V. Check Speaker Output and Audio Input voltage. Here you get no voltages 0.00V. If you get same voltages, then connect preamplifier to input and connect speaker to output.

Power Supply:- For get best performance of this amplifier, you use 18-0-18V to 24-0-24V 5A-6A Transformer (Don't increase voltage).

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