Class D Amplifiers Are Having a Moment
For years, Class D amplifiers were associated with powered subwoofers and budget consumer electronics. That reputation is rapidly changing. In 2025, Class D technology has matured to a point where even committed audiophiles are embracing it — and for good reason.
What's Driving the Class D Revolution?
Several technological shifts have converged to push Class D into high-fidelity territory:
- Advanced GaN (Gallium Nitride) transistors: GaN switches far faster than traditional MOSFETs, enabling higher switching frequencies that push distortion artifacts well above the audible range.
- Improved output filters: Modern Class D output filters are better engineered, reducing noise and improving frequency response far into the high-frequency range.
- Ncore and Purifi modules: Hypex's Ncore and Purifi's Eigentakt platforms set a new standard for measurable Class D performance, with distortion figures that rival or exceed the best Class A designs.
- Better power supply design: Switching power supplies have improved alongside the amplifier stages, reducing noise floors and improving dynamic range.
Notable 2025 Developments
Purifi 1ET9040BA Module
Purifi Audio — the Danish engineering firm founded by Bruno Putzeys and Lars Risbo — continues to push the envelope with updated Eigentakt modules. The latest iterations offer even lower distortion at higher power levels, and an increasing number of boutique amplifier manufacturers are building products around these modules.
Pascal and ICEpower Updates
Bang & Olufsen's ICEpower division remains a key supplier to many amplifier brands. Their newer modules feature improved EMI filtering and compatibility with a wider range of speaker loads, addressing one of Class D's traditional weaknesses.
GaN-Based Integrated Amps
Several brands have announced or released integrated amplifiers built around GaN power stages in the 2024–2025 window. These designs combine the efficiency of Class D with power supply simplicity, resulting in compact, cool-running amplifiers with impressive measured performance.
Class D vs. Traditional Amplifier Classes in 2025
| Aspect | Class A/B | Class A | Modern Class D |
|---|---|---|---|
| Efficiency | 50–70% | 20–30% | 85–95% |
| Heat Generation | Moderate | High | Very Low |
| THD+N (good designs) | 0.001–0.01% | 0.01–0.1% | 0.0003–0.005% |
| Size & Weight | Large/Heavy | Large/Heavy | Compact/Light |
| Audiophile Acceptance | Established | Revered | Growing Rapidly |
Who Should Pay Attention?
Class D in 2025 is worth consideration for:
- Audiophiles in warm climates where Class A heat output is impractical
- Listeners who prioritize low distortion measurements
- Anyone building a compact, high-powered system
- Those powering difficult speaker loads (low impedance, low sensitivity)
Looking Ahead
The gap between Class D and traditional amplifier topologies continues to narrow. As GaN technology matures and more talented engineers apply themselves to Class D design, it's increasingly difficult to justify dismissing it on sonic grounds alone. 2025 may well be remembered as the year Class D crossed firmly into audiophile-grade territory.