Why do high-end differential headphone amplifiers achieve virtually unmeasurable distortion and complete rejection of power supply hum? The secret lies in active current-mirror loads—transistor circuits that replace ordinary resistors to provide massive open-loop gain and sky-high Common-Mode Rejection Ratios. The Physics of Active Current-Mirror Loads In analog amplifier … [Read more...] about Current-Mirror Active Loads: High Open-Loop Gain in Differential Amps
Blog
Servo DC Bias Control: Eliminating Output Coupling Capacitors
Why do high-end headphone amplifiers go to great lengths to eliminate output coupling capacitors? Because even the finest electrolytic capacitors introduce dielectric absorption, phase smear, and low-frequency distortion—problems solved permanently by active DC servo bias control. The Electroacoustic Flaws of Coupling Capacitors In single-supply and conventional … [Read more...] about Servo DC Bias Control: Eliminating Output Coupling Capacitors
Diamond Buffer Output Stages: Fast Current Delivery in Headphone Amps
Why do conventional emitter-follower output stages struggle to deliver clean, effortless current into difficult 16-ohm planar headphones? The diamond buffer output stage arranges complementary transistors in a cross-coupled diamond bridge, delivering massive transient peak current with zero global feedback. The Physics of the Diamond Buffer Architecture In solid-state … [Read more...] about Diamond Buffer Output Stages: Fast Current Delivery in Headphone Amps
Folded Cascode Gain Stages: High Slew Rate and Low Phase Shift
How do modern reference solid-state headphone amplifiers achieve blazing 200 V/µs slew rates and 100 MHz bandwidth without bursting into high-frequency oscillation? The secret lies in the folded cascode gain stage—an analog topology that completely eliminates Miller capacitance. The Physics of Miller Capacitance in Voltage Gain Stages In traditional two-stage operational … [Read more...] about Folded Cascode Gain Stages: High Slew Rate and Low Phase Shift
Single-Ended Triode Output Stages: Harmonic Distribution in Amps
Why do single-ended triode (SET) tube amplifiers sound so richly musical and holographic to the human ear despite measuring higher total harmonic distortion on bench analyzers? The secret lies in the psychoacoustics of human auditory masking and monotonic second-harmonic decay. The Physics of Single-Ended Triode Transfer Curves Single-ended triode (SET) amplifier … [Read more...] about Single-Ended Triode Output Stages: Harmonic Distribution in Amps