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    For audio amplifier, should one used discrete transistors or an opamp, pros and cons?

    One can use an opamp to amplify circuit as well as a BJT or FET. They all have difference frequency responses, voltage range, power limit and requirements and circuit complexity. Anyway, for making an audio amplifier should one merely use discrete transistors perhaps a voltage follower (common collector) for current gain preceded by a common emitter stage, or just use opamps?

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    Re: For audio amplifier, should one used discrete transistors or an opamp, pros and c

    Op amps are in popular audio amplifier IC's such as LM383, LM386, TDA2002, etc.

    Some provide several watts. Some have internal biasing networks allowing you to use a single supply.

    It is also possible to make the pre-amp from a low-power op amp, then feed that to an H-bridge of discrete power transistors.



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    Re: For audio amplifier, should one used discrete transistors or an opamp, pros and c

    Hi,

    it depends on your needs.

    If you want cheap audio amplifier you will find a lot on ebay.
    If you want high power amplifiers you should consider to use Class D types.
    If you want HIGH END, then you may build it on your own. but then for sure without OPAMPs .. It´s a pilosophy ...

    Klaus


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    Re: For audio amplifier, should one used discrete transistors or an opamp, pros and c

    Many audio opamps such as the OPA134, 2134 and 4134 have very low distortion, very low noise and full output to 250kHz. This opamp or the dual or quad can be used to drive driver and output transistors in a very good audio amplifier.

    An LM3886 power amplifier IC provides 60W into 4 ohms or 30W into 8 ohms with 0.03% distortion from 20Hz to 20kHz. Two ICs can be paralleled with series resistors and two groups of series ICs can be bridged for much higher output power.

    Texas Instruments makes some excellent high power class-D audio amplifier ICs.


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