Class-D vs Class-AB Amplifier: Key Differences & Which One to Choose

Class-D vs Class-AB Power Amplifier

Which One Is Better for Modern PA & Commercial Audio Systems?

When choosing a power amplifier for a PA system or commercial audio installation, one of the most common questions is:
Class-D vs Class-AB amplifier — which is better?

Both amplifier classes are widely used in professional audio, but they differ significantly in efficiency, size, heat dissipation, power consumption, and application scenarios. This article will help you clearly understand the differences and choose the right solution for your project.

What Is a Class-AB Power Amplifier?

A Class-AB power amplifier combines the advantages of Class-A and Class-B designs. It has long been used in traditional professional audio systems.

Key Characteristics of Class-AB Amplifiers

• Moderate efficiency (typically 50–60%)

• Good linearity and sound quality

• Larger power transformer and heat sink required

• Higher heat generation

• Heavier weight and larger chassis size

Typical Applications

• Traditional sound reinforcement systems

• Audio setups where rack space and power consumption are not critical

What Is a Class-D Power Amplifier?

A Class-D power amplifier, also known as a digital power amplifier, uses high-frequency switching technology to amplify audio signals with extremely high efficiency.

Key Characteristics of Class-D Amplifiers

• Very high efficiency (up to 90% or more)

• Significantly lower heat dissipation

• Compact and lightweight design

• Lower power consumption

• Ideal for high-power and long-running systems

Typical Applications

• PA systems

• 70V / 100V distributed speaker systems

• Commercial audio installations

• Background music systems

• Modern rack-mounted installations

Class-D vs Class-AB: Key Differences at a Glance

Why Class-D Amplifiers Are Dominating Modern Installations

In modern commercial audio and PA system design, efficiency and reliability are critical. Compared with Class-AB amplifiers, Class-D power amplifiers offer clear advantages:

• Lower operating cost due to reduced power consumption

• Less heat, improving long-term stability

• Smaller rack footprint, ideal for equipment rooms

• Higher output power in compact designs

• Perfect match for 70V / 100V constant voltage speaker systems

This is why Class-D amplifiers have become the preferred choice for shopping malls, hotels, schools, office buildings, conference centers, and large distributed audio systems.

Sound Quality: Is Class-D as Good as Class-AB?

With modern circuit design and components, today’s Class-D amplifiers deliver excellent audio quality, meeting and exceeding the requirements of most commercial and professional applications.

For PA systems, background music, voice evacuation, and installation audio, the difference in sound quality between high-quality Class-D and Class-AB amplifiers is negligible, while Class-D clearly wins in efficiency and practicality.

Which Amplifier Should You Choose?

Choose Class-D Power Amplifier If:

• You need high power output

• Your system runs long hours

• Rack space is limited

• Energy efficiency is important

• You are building a 70V / 100V PA system

Choose Class-AB Power Amplifier If:

• You prefer traditional designs

• Power efficiency is not a concern

• Installation space is sufficient

Conclusion: Class-D Is the Future of Commercial Audio

While Class-AB amplifiers still have their place, Class-D power amplifiers are rapidly becoming the standard for modern PA and commercial audio systems. Their combination of high efficiency, compact design, and reliable high-power output makes them the smarter choice for today’s installations.

Brands like LYINTL focus on developing high-power Class-D amplifiers that meet the real-world needs of system integrators and installers worldwide.