Headphones Amplifier

Headphones Amplifier Characteristics of the headphone amplifier shown 🎧 Type of amplifier • Class AB headphone amplifier • Discrete Diamond Buffer output stage • Voltage amplification provided by an op-amp • Power stage separated from the voltage-gain stage 👉 A classic, clean, and technically correct architecture for high-quality audio. ⸻ 🔊 Target load impedance • Optimized for 32 Ω • Can comfortably drive: • 16–32 Ω (high current demand) • Up to ~300 Ω (limited by voltage rather than current) ⸻ ⚡ Current capability • Symmetrical push-pull output stage • 10 Ω emitter resistors → good thermal stability • Estimated peak output current: >80–100 mA 👉 More than sufficient for low-impedance headphones without stress. ⸻ 🔋 Power supply • ±10 V dual supply • Local decoupling: • 100 nF (high-frequency) • 220 µF (energy reserve) 👉 Supply rails well suited for: • Adequate headroom • Low distortion • Avoiding clipping with modern DACs ⸻ 📈 Gain • Voltage gain ≈ 4.1× (+12.3 dB) • Very well chosen value: • Not excessive • Compatible with 2 Vrms sources • Allows good volume control range ⸻ 🔇 Noise performance • Moderate gain • Op-amp isolated from the load • Discrete buffer with stable biasing 👉 Low noise floor, suitable even for IEMs if a low-noise op-amp is used. ⸻ 🎚️ Distortion • Diamond Buffer reduces: • Crossover distortion • Dynamic loading of the op-amp • Emitter resistors improve linearity 👉 Low THD even near the maximum useful output level. ⸻ 🔁 Stability • 47 Ω series resistor between op-amp and buffer • Compensation capacitors (100 pF) 👉 Very stable with: • Capacitive loads • Long cables • Different headphone types ⸻ 🔌 Output impedance • Low, mainly determined by: • Emitter resistors • Buffer topology 👉 Estimated < 1 Ω • Good damping factor • Proper driver control ⸻ 🔊 Typical output power Into 32 Ω: • Useful continuous power: 50–100 mW • More than enough for real listening levels • Comfortable dynamic headroom ⸻ 🎯 Executive summary This headphone amplifier is characterized by being: • Properly dimensioned (no excess) • Low noise • Stable • High current capability • Sensible gain • An honest engineering design, not marketing-driven It is exactly the kind of circuit a competent engineer would design for headphones, not to advertise “watts.”