Breaking Down Audio Amplifier Classes: A vs B vs AB vs D

Breaking Down Audio Amplifier Classes: A vs B vs AB vs D

Subtitle: Understand the differences, efficiency, and sound quality between amplifier classes – and why Class D is leading the future.

When it comes to audio amplification, not all amplifiers are created equal. Each class of amplifier has its unique characteristics, strengths, and trade-offs. At The Cult Audio, we believe understanding these distinctions helps users and professionals make better decisions when choosing or repairing audio systems.

Class A Amplifiers

Overview: Class A amplifiers are known for their excellent linearity and low distortion. They operate with the output devices conducting at all times, regardless of the input signal.

Pros:

  • Superior sound quality

  • Minimal crossover distortion

Cons:

  • Very low efficiency (typically 20-30%)

  • Generates significant heat

  • Bulky heatsinks required

Use Case: Mostly used in high-end audiophile equipment where sound purity is prioritized over efficiency.

Class B Amplifiers

Overview: Class B amplifiers improve efficiency by splitting the waveform between two devices: one handles the positive half, and the other handles the negative half.

Pros:

  • Better efficiency than Class A (up to 70%)

  • Lower heat output

Cons:

  • Crossover distortion at the zero-voltage point

  • Not suitable for high-fidelity audio

Use Case: Rarely used alone in modern audio applications due to distortion drawbacks.

Class AB Amplifiers

Overview: Class AB amplifiers combine elements of both Class A and Class B to reduce distortion while improving efficiency.

Pros:

  • Balanced performance

  • Improved efficiency (50-60%)

  • Lower distortion than Class B

Cons:

  • Still generates considerable heat

  • More complex circuit design

Use Case: Widely used in consumer audio systems, professional gear, and automotive amplifiers.

Class D Amplifiers

Overview: Often misunderstood, Class D amplifiers are not "digital" but rather use high-frequency switching to amplify audio signals. They're extremely efficient and compact.

Pros:

  • High efficiency (90%+)

  • Minimal heat generation

  • Compact and lightweight

Cons:

  • Historically associated with poor audio quality (now significantly improved)

  • Requires proper PCB design and EMI filtering

Use Case: Ideal for portable systems, home theaters, automotive audio, and modern repair applications. At The Cult Audio, many of our products are based on advanced Class D topology, ensuring reliable performance in compact form factors.

Conclusion

Each amplifier class has a place in audio electronics, depending on the application and requirements. For modern use cases where space, efficiency, and thermal management are crucial, Class D amplifiers represent the future. At The Cult Audio, we specialize in high-performance Class D amplifier boards built for both professional repair work and audio enthusiasts.

Explore our lineup and experience the evolution of audio amplification.

Made in India | Engineered for Quality | Trusted by Repair Professionals

Back to blog