7-band equalizer with wide control range - Control range: ±12 dB across seven bands: 60 Hz, 150 Hz, 400 Hz, 1 kHz, 3 kHz, 6.5 kHz, 15 kHz - Circuit built with TI or ST TL074 Basic parameters and amplification - 7-band sound equalizer preamp amplifier - Classic op-amp 4580 provides 5x gain (14 dB) - Input impedance: 20 kΩ; output impedance: 600 Ω Headphone amplification and fit - NE5532 based balanced headphone amplifier drives the 47 earbud driver circuit - Designed to easily drive different headphones with adjustable height for a better fit Connectivity and interface - 3.5 mm input interface supports a 4-pin plug - Output connected to a headset with microphone for normal mobile calls - Also includes an RCA interface connector Use scenarios - Portable listening with a smartphone or computer, customizing tone for music and calls - Desktop or studio-style headphone monitoring with precise gain and tonal control - Voice calls and video conferencing with integrated mic compatibility and adjustable headset fit Key benefits - Precise tone shaping with a wide 7-band range and clear separation between bands - Reliable gain and impedance characteristics suitable for standard headphones and line-level sources - Flexible connectivity supports mobile calls, RCA equipment, and various headset configurations - Easy headphone compatibility with adjustable fit for different hardware setups