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headphone amplifier circuit schematic

Headphone Amplifier Circuit Design

Typically, a headphone is connected to the loudspeaker output of the final amplifier stages through a voltage divider circuit. However, this simple design has two distinct disadvantages. Firstly, the headphone volume cannot be varied independently from the main speaker when the main speaker is switched on at the same time. Secondly, the voltage divider circuit causes attenuation at the same time affects the bass output negatively.

The solution to this problem is an independent amplifier for the headphones such as the circuit presented bellow. This headphone amplifier circuit is connected to the output of the final amplifier through the potentiometer P1. IF a stereo headphone is used, this potentiometer must be replaced with a stereo type. Furthermore, the entire circuit must be duplicated for the second channel.

The headphone amplifier delivers an output of around 1 watt. Use a power supply rated at 350 mA. The amplifier gain is dependent of the resistors R4 and R6. The values shown in the circuit gives a gain of 11. The voltage at the junction of R13 and R14 must be set at 50% of the power supply. This can be set through P2. The standby current through the final transistors is about 50 … 110 mA.

Headphone amplifier circuit diagram

headphone amplifier circuit schematic

3 Comments

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  • KROKKENOSTER

    Matey but you will have a stack of ooomph with this baby if those outputs can handle the current! I will not go near that with headphones that are the highest impedance available because the output look like in the order of several watts!!

  • msw1onlygmail-com

    i have a 4558d amp chip but need a scematic with pics of the finished boardso i can make an amp for my phone can i get some help.this will be my first attempt to make something

  • Ali

    Dear Popescu Marian
    The designs are exelent.
    I forward most of your mails to some of my firemds.
    At your regard
    Ali

    thanks

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