Simple Low-Noise Audio-Distribution Amplifier
This article describes a low-cost audio-distribution low noise amplifier based on hybrid or mixed technology. Input to the amplifier is from low-noise, high-gain npn transistor. Output buffers are implemented with voltage followers using an operational amplifier (op-amp). The combination of low-noise transistor and push-pull output stage of the op-amp guarantees good characteristics of the hybrid amplifier.
Often we are required to send signals from one audio source to many loads/speakers. For that we use audio-distribution amplifiers. This circuit employs low-noise bipolar transistor BC550 and op-amp LM324, which are widely available at low cost.