Various type of amplifier and pre-amplifier circuit has appeared in this website in amplifier and pre-amplifier section. The circuit posted here is of DIY headphone amplifier which is suitable for headphone or 8-ohm speaker or more impedance. The circuit is so designed that it has no risk of overloading or distortion of either the circuit or headphone.
Circuit Description DIY Headphone Amplifier using 741 IC
The heart of the circuit headphone amplifier is op-amp 741 which provide suitable gain where the transistor T1 and T2 are used to drive low impedance headphone. The biasing of transistor is provided by diode D1 and D2 to reduce crossover distortion. The low frequency response is detected by capacitor C4 and is so chosen to give lower cut-off frequency of about 20 Hz with an 8-ohm load.
The input of this circuit is connected to preamplifier circuit or any other source must delivering 100mV to 2.5V peak-to-peak with high output impedance. Variable resistor VR1 is used to control volume. In case even with the potentiometer at the maximum level the output is not sufficiently high then increase the value of resistor R3.
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PARTS LIST OF DIY HEADPHONE AMPLIFIER USING 741 IC
| Resistor (all ¼-watt, ± 5% Carbon) |
| R1, R2, R7 = 47 KΩ
R3 = 220 KΩ R4, R5 = 4.7 KΩ R6 = 22Ω VR1 = 10 KΩ |
| Capacitors |
| C1 = 10 µF, 25V (Electrolytic capacitor)
C2 = 1 µF, 10V (Electrolytic capacitor) C3, C4 = 10 µF, 10V (Electrolytic capacitor) |
| Semiconductors |
| IC1 = 741 (General purpose operational amplifier)
T1 = BC548 (general-purpose NPN bipolar junction transistor) T2 = BC558 (Audio amplifier silicon PNP transistor) D1, D2 = 1N4148 (Small Signal Diode) |
| Miscellaneous |
| LS1 = Headphone |
Can you please give me a proper description of the working of the circuit and also a few more details on how to give the input to the circuit.
Hello, I liked this project I will develop it, a doubt would be R1, R2 and C1 because of the use of them?
These components are used in order to avoid risk of overloading and distortion.
can you tell me what application that use 3 ic of 74hc
Hey tell me where to place R6 in the circuit.
There are two R7 in the circuit diagram.