How to Make D718 And B688 Stereo Audio Amplifier Easy Circuit

    How to Make D718 And B688 Stereo Audio
 Amplifier Easy Circuit

Use of Audio Amplifiers

Audio amplifiers are circuits used to Convert low audio signals from mobile or other devices to high power Audio signals for drive Speakers Subwoofer or Headphones

Easy way to make powerful audio amplifier without ic circuit without PCB

How to Make Audio Amplifier 

Circuit Diagram: 

What is Stereo Audio Amplifier

Stereo Audio Amplifier is two Channel Amplifier Mean It Receive Two  low power Left and right Signals and convert into High Power Signals for Left and Right Signals you can say Stereo are two Amplifiers one for left speaker and Second for right.

Some Pictures Steps may help you:

D718 Amplifier Transistors


B688 Amplifier Transistors


1000uf  dc Capacitors any voltage

150 Kilo Ohms Resisters

Heat sink for four Transister

Some Heatsinks are Conductive So use Paper as emulsion 

Arrange Transistors Like This Pattern 

1st B688   2nd D718   3rd B688  4th D718

See in Picture Transistors Pins

Base Collector Emitter

Attach 150K Resister to 1st B688 Emittor to 2nd D718 Base


Attach 150K Resister to 3rd B688 Emittor to 4th D718 Base

Like Picture

Join 1st B688 Base to 2nd D718 Collector
Join 1st B688 collector to 2nd D718 emitter


Join 3rd B688 Base to 4th D718 Collector
Join 3rd B688 collector to 4th D718 emitter

Attach Capacitor + terminal to 2nd D718 base


Attach Capacitor + terminal to 4th D718 base

 audio in Cable pins Diagram
Left Right Gnd

Attach Left orange 2nd D718 Capacitor - terminal
Attach Right White 4th D718 capacitor - terminal
Attach GND Blue to 4th D718 emitter

Like picture circuit Diagram

joint 2nd D718 emitter with 3rd B688 collector

   Like a Diagram

See diagram Connect 4-8 ohm Speakers to the amplifier

Joint Speakers + + Wires

and connect 1 negative speaker wire to first b688 emitter

and connect 1 negative speaker wire to Second b688 emitter

Input Wires 

Connect + input Wire to speakers jointed positive point+


Negative Input wire to Last D718 Emitter point

Input voltage 6volt to 12 volt

Components Guide
1. D718 ( 2 , pcs ) you can also use any other Powerfull amplifier Transister Like ( C5200)

2. B688 ( 2, pcs ) you can also use any other Powerfull amplifier Transistors Like ( A1943)

3. 150 Killo ohm Resisters ( 2pcs) also use 100 Killo ohms Resisters 

4. 1000uf capacitor also use any other values Capacitors ( 470uf - 2000uf)

5. three-pin audio input Cable

6. Heatsinks for the transistor to protect from overheat

7. Speakers 4 - 8 ohms 

8. input supply 6-12 volts

Sound is Great pls make according to the circuit diagram if the circuit
not work or any vibrating sound
Check audio in cable and Transistors
not give high voltage power supply it can damage your Speakers

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  1. Apply white flux paste to the surfaces to be soldered. It’s important to use a flux suitable for stainless steel as it needs to etch the surface so that the solder can bond properly.


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