Key benefits Boosts low amplitude audio signals to drive a power amplifier, improving playback volume and clarity from devices with weak outputs Uses a NE5532 dual opamp for low noise and reliable performance Provides a fixed gain of 20 dB (approximately 10 times) for consistent amplification Front 3.5 mm jack enables direct headphone connection for monitoring or casual listening Simple DC power operation with a supply range of 9 to 19 V, compatible with common DIY audio setups What this circuit offers Amplifier chip: NE5532 dual opamp for stable, low noise amplification Gain: 20 dB (about 10x) suitable for small audio signal amplification Power supply: DC 9 to 19 V to support typical hobbyist and project use Input/output: front 3.5 mm interface can be connected to headphones for direct listening or monitoring Purpose: designed to be used when your device output is too quiet for a power amplifier, enabling strong, clear amplification before driving the next stage Technical specifications at a glance Amplifier chip: NE5532 dual opamp Gain: 20 dB (approximately 10x) Power supply: DC 919 V Output/monitoring: front 3.5 mm headphone jack Application: suitable for small audio signal amplification to improve drive for power amplifiers 23 practical use scenarios Scenario 1: You have a portable audio source with a weak output. Install this circuit to boost the signal before feeding a power amplifier, resulting in louder, clearer sound without increasing source gain. Scenario 2: DIY audio projects. Use the circuit to interface a small signal source (such as a DAC or MP3 player) to a dedicated amplifier stage, with headphone monitoring available via the front jack. Scenario 3: listening from low output devices. Connect headphones through the front 3.5 mm jack to enjoy listening at comfortable levels when the source output is insufficient. Notes on compatibility and operation Compatible with DC power supplies in the 9 to 19 V range Designed for small audio signal amplification and direct headphone monitoring No additional amplification stages required for basic operation, making it suitable for integration into hobby or professional audio projects