DIY Antennas, QRP, SDR & Ham Radio Projects from VU3DXR
The audio category collects everything related to sound in your shack: microphone preamplifiers, speech processors, tone generators, practice oscillators, test signals, and audio troubleshooting guides. You’ll find circuits like simple 2N3904 mic preamps for uBITX, audio peak limiters, speech processors, UJT code practice oscillators, pink noise generators, and sine‑wave sources, all tuned for amateur‑radio and hobby use
This dual-microphone noise cancellation circuit uses two microphones placed back-to-back, with one signal inverted and summed using an LF351 op-amp to cancel common ambient noise. It preserves the desired voice signal while reducing background noise, improving clarity in noisy environments
This noise-canceling condenser microphone design uses dual electret microphones with op-amp stages to reduce ambient noise. One mic captures the desired audio while the other picks up background noise, which is inverted and summed to cancel interference, improving clarity for communication and recording.
This microphone compressor circuit utilizes a two-stage amplification design for dynamic range control. Initially, the input signal enters through MK1, a microphone input connector. Subsequently, the signal passes through C1 and C3 coupling capacitors for DC blocking. The first amplification stage employs Q1, a 2N3904 transistor configured as a common emitter amplifier. Meanwhile, R1 provides […]
This dynamic speech compressor with audio preamplifier combines a transistor-based preamp and op-amp gain stage with diode-controlled compression to regulate signal levels. It automatically reduces loud peaks and boosts weak audio, delivering consistent output with adjustable threshold, attack, and release timing for clear speech and improved transmission quality.
Simple audio compressor for SSB HF Radio rigs An audio/speech compressor is a device that reduces the dynamic range of the audio signal. This means that it makes the loud parts of the signal quieter and the quiet parts of the signal louder. This can be useful for SSB HF radio rigs because it can […]
NE555 based Microphone amplifier IC NE555 or commonly known as 555 is an IC that is well known among electronics practitioners as an IC for timers, and can be used to form monostable or bistable multivibrator circuits. But not many know that the 555 IC can also be used as an audio signal amplifier. By […]
Stop fading into the noise! Build this simple, low-cost speech compressor using the LM324 quad op-amp to ensure your voice stays loud and clear on the airwaves.
Audio processors and Speech compressors are important in SSB radio because they can help improve the transmitted signal’s quality. Here are complete resources and links available in the internet connected to Mike Preamplifier/Speech compressors/Speech Processors Dyna Audio compressor Noise Canceling Electret Microphones – WB9YBM Microphone Speech Processor Microphone Amplifier with ALC Audio compression with transistors […]
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.
SSM2167 audio processor for Baofeng Mic enclosure Mic gain is barely adequate on the µBITx transceiver since there is no Mic Gain control. It would also be helpful to not only provide mic gain control, but to add compression in order to boost the average power output.The SSM2167 is a powerful audio processor that can […]