The New Era of Class D Amplifiers: When Perfection Goes Beyond Measuring Machinery

In audio laboratories, the Audio Precision AP555 is considered the most expensive and accurate measuring machine in the world. However, when engineers used it to measure the distortion of the latest Class D amplifier from ICEpower (model SC400A2), this machine encountered a continuous scale jump error.

The reason is extremely surprising: The amplifier processes the signal so cleanly that the AP555 cannot find any distortion. At that measuring range, the expensive machine is actually just measuring the level of internal electrical noise... itself. With a distortion (THD+N) of just 0.0002%, ICEpower has officially pushed Class D technology to a new level, making comparisons with traditional Class A amplifiers obsolete.

Why was Class D once criticized, but Class A was revered?

In the past, early Class D amplifiers were often criticized by Audiophiles as having a cold, dry or harsh sound. The core reason is that this technology produces a fairly large amount of signal noise (about 0.3%) in the 6 - 7 kHz frequency range. This is exactly the sound range that the human ear is extremely sensitive to. In the past, many measurements often intentionally hid this noise level, but demanding audio players have discovered it.

With the new generation SC400A2, ICEpower has reduced the noise level in the high frequency range by 10 to 30 times. All glare has been completely eliminated.=

Technological secret: Smart self-correcting circuit

Every amplifier faces the problem that the audio signal transmitted from the machine to the speaker will always be slightly distorted due to the resistance of the wire or the physical characteristics of each speaker. To solve it, ICEpower applies a system called Dual Nested Feedback Loop. This system can be understood as an extremely agile proofreader placed right next to the audio output port. Its task is to continuously take the sound that is about to be emitted from the speaker and compare it with the original music. If it detects even the slightest deviation, it will immediately calculate and automatically compensate, correcting the signal flow immediately. Thanks to this high-speed error correction mechanism, the amplifier produces an absolutely flat sound response (+0.0/-0.1 dB). No matter how difficult a speaker you plug it into, the sound comes out exactly like the original recording. Thanks to the nature of Class D technology, the SC400A2 module achieves a power conversion efficiency of up to 94.5%. When the device is left in standby mode without playing music, it only consumes a mere 7.6W.

Race at the top: Class D versus Class D

With this parameter, ICEpower is no longer concerned about competing with Class A anymore. Their only competitor currently is Purifi's Eigentakt 1ET400A module. Both are Class D masterpieces that reach almost zero distortion, using the same highest-end components. Purifi has a slightly quieter platform specification, while ICEpower excels in the width of the frequency range and a more convenient design that combines both audio channels into one ultra-compact board. But in reality, these gaps are now only meaningful on paper. The human ear is completely unable to distinguish the difference between those extremely small indicators, and both are far beyond the noise limit of any music room.