This article is an Amplifier Architecture Primer aimed at helping readers understand technical terms and concepts often used in amplifier reviews and marketing. The article discusses different types of amplifier circuits, amplifier classes, and output coupling methods.
Amplifiers are divided into two fundamental groups: single-ended amplifiers and push-pull amplifiers. Single-ended amplifiers amplify the entire signal from input to output and are simple but less efficient. They tend to produce pleasant harmonic distortion. Push-pull amplifiers amplify two mirror images of the signal and combine them at the output, resulting in higher power and efficiency, but with added complexity.
Amplifier classes refer to how current flows in the amplifier during operation. Class A amplifiers constantly conduct current and have lower distortion, but they are less efficient and generate more heat. Class B amplifiers switch off when not needed for higher efficiency but suffer from crossover distortion. Class AB amplifiers strike a balance by always having some current flowing, offering better efficiency and lower heat generation.
Output coupling describes how the amplifier connects to the headphones. Direct coupling is the purest connection but can introduce DC offset issues. Capacitor coupling is a common method that uses capacitors to pass audio signals while blocking DC voltages. Each coupling method has its pros and cons.
Overall, understanding amplifier architecture can help consumers make more informed choices when selecting audio equipment.