Audio Circuits



Buffer Amplifier

The buffer amplifier is an important stage of any audio amplifier for proper matching between two stages as well as to match any high impedance transducers such as Electret Microphone, Carbon Microphone, Crystal Microphone, Crystal Pick-up Unit, Radio Tuner, Magnetic Pick-up, Digital signal Pick-up Unit etc.

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Miniature Size Amplifier

This miniature amplifier operates only on 1.5V battery. In case of application as Hearing Aid the battery shall be button cell. The headphone shall be of Mono type of 32 ohms impedance. All other components shall be SMT type to build the amplifier in a miniature size PCB. The PCB shall be approximately 1-square inch size.

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Scratch & Rumble Filter

The circuit for Scratch Noise and Rumble Noise filter has been described in the attached link. This filter is used in the series of any audio pre-amplifier stage to filter the scratch noise as well as rumble noise. By using this circuit Bass and treble cut are produced by a RC Network

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Sound Source Width Control

The Sound source width control has been used to control the width of the sound source in a stereophonic audio system that can varied continuously. Part of the signal voltage of the one channel is added to the second channel. One 10K LIN Ganged potentiometer are used to control the sound source width continuously between in-phase crosstalk of about 100% (corresponding to mono operation) and anti-phase crosstalk of 23%.

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Transistorized Hi-Fi Amplifier (3 Watt)

The amplifier described here is placed for the learners / Beginners / Students. The 3-Watt Output power of this amplifier is sufficient for a standard or average sized room. The amplifier circuit described below uses six (06) silicon transistors. Since all these transistor stages are directly coupled it ensures excellent low frequency response. The use of silicon transistors provides greater stability to the amplifier and improves the high frequency response also.

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Transistorized Hi-Fi Amplifier (15 Watt)

Now a days there are many more Integrated Circuits available in the market to make one Audio Amplifier. But, within the circuitry everything has to be taken care by the Audio Amplifier IC itself and the experimenter’s have nothing to do or learn anything on it. But, if you would like to and learn something regarding the…

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Transistorized Hi-Fi Amplifier (25 Watt)

In this 25W Hi-Fi Amplifier described in details are capable to deliver truly 25Wr. M. s. power. Silicon transistors have been used in all stages. Power transistors 2N 3055 or BD 182 has been used in the power output stage.

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Transistorized Hi-Fi Amplifier (40 Watt)

This 40W Hi-Fi Amplifier described in details are capable to deliver truly 40W r. m. s. power. Silicon transistors have been used in all stages. Power transistors 2N 3055 or BD 182 has been used in the power output stage. The output power transistors should be Matched Pair and the output stage employs in a quasi-complimentary single…

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Transistorized Balance Control Circuit

The balance control circuit is an important stage of a stereo amplifier. The function of a balance control circuit is to vary the voltage gain in both the channels by 6dB in opposite directions. This works directly in a stereo amplifier.

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Electronic Circuits – Simplified