DIY Antennas, QRP, SDR & Ham Radio Projects from VU3DXR
Technical guides for building amateur radio Microphone Preamplifier . From 3-transistor compressors to low-noise speech amplifiers, get the circuits you need for better TX audio at VU3DXR
This article presents a simple, low-cost audio compressor circuit designed to stabilize microphone signal levels. It reduces dynamic range by softening loud sounds and boosting weak ones, improving clarity and intelligibility. Built with basic components, it suits amateur radio and DIY audio setups, offering consistent output without complex or expensive hardware.
This article describes a simple microphone compressor built with three transistors to improve audio consistency. The circuit uses a preamplifier, buffer, and feedback stage to control gain. As input increases, negative feedback reduces amplification, compressing louder signals. It runs on 12V and suits amateur radio setups needing stable, balanced voice output.
This project uses an SSM2167 IC as a complete microphone preamplifier with built-in compression and noise gating to improve uBITX transceiver audio. It boosts mic gain, reduces dynamic range, and suppresses background noise, resulting in clearer, louder, and more consistent transmitted speech.