Chip and purpose Amplifier chip: NE5532 dual operational amplifier, providing reliable, lownoise performance in a small signal path. What it does and why you need it Boosts a low output from your source to drive a power amplifier more effectively, helping when your device volume is too quiet. Delivers a clear 10x gain (20 dB) for small audio signal amplification, improving overall listening levels without requiring extra equipment. Front 3.5 mm interface allows direct connection to headphones for convenient monitoring and testing. Compatibility and performance Power supply: DC 9–19V, suitable for standard lowvoltage audio setups. Designed to work as a simple gain stage before a power amplifier, enhancing compatibility with a range of audio sources and amplification chains. 23 practical use scenarios Scenario 1: A portable music player or smartphone with low output connected to a power amplifier for home listening; the circuit provides the needed gain to achieve comfortable playback levels. Scenario 2: A DIY audio project requiring a compact 20 dB gain stage with headphone monitoring via the front 3.5 mm jack, suitable for testing and listening checks. Scenario 3: A smallsystem setup where a lowsignal source must be paired with a higherpower amplifier, enabling better matching and improved dynamic range without altering the source device.