D718 Stereo Bass Amplifier with MP3 Bluetooth

Here I will show you, how to make a powerful D718 Stereo Bass Amplifier with MP3 Bluetooth. I used 4 nos D718 NPN transistors which I will connect each other in parallel.

MP3 player kit is also attached which allows users to use USB device, memory card and their mobile. I demonstrated the circuit with 12 volts DC power supply of 5 amperes but you can use 12 volts to 18 volts DC. I used 4 ohms 35 watts speakers which provided a greater sound.

Circuit diagram

used in D718 Stereo Bass Amplifier

Following circuit diagram contains D718 Stereo Bass Amplifier with MP3 Bluetooths.

More Circuit Layouts

List of components

• 2SD718 transistor x 4
• 4700uf capacitor x 1
• 220uf capacitor x 1
• 104 capacitor x 4
• 680 ohms / 1 watt resistor x 1
• 100k ohms resister x 2
• 68 ohms/1w resister x 2
• 47k resister x 2
• 1k ohms resistor x 3
• 2.2k ohms resistor x 2
• 50k potentiometer x 3
• MP3 bluetooth kit x 1
• Power supply 12v DC
• speaker 4 ohms
• Connectors and volume knobs are optional.

Development images

used in D718 Stereo Bass Amplifier

Step-1
Take four nos of d718 npn transistors, heat sink and 4 nos mica (rubber insulation). Fix or tighten all transistors onto the heat sink with mica so that the base plates of all transistors could not touch the heat sink. The Collector Pin of transistor d718 is internally connected with base plate. This is the reason with use mica to separate them with the heat sink.

Step-2
Firstly, take two 100k resisters. Connect one resister to pin-1 (base) & pin-2 (collector) of left first transistor. Then connect/solder second resister to pin-1 (base) & pin-2 (collector) of left third transistor.

Now take two 68 ohms/1w resisters. Solder first resister with pin-3 (emitter) of first left transistor. And other side to pin-1 (base) of second transistor from left. And repeat same with third and fourth transistor with the second 68 ohms/1w resister.

Take two 47k resisters. Solder one resister with pin-1 (base) of first left transistor and pin-3 (emitter) of second left transistor. Also repeat same with third and fourth transisters with the second 47k resister.

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