People in the industry have always been very clear that the power stage of integrated amplifiers below 10,000 yuan is not worth considering, especially the newly released integrated amplifiers, which have seriously reduced power stages and inflated power, and this extends to all integrated amplifiers.

Actually, years ago, there was no such thing as cutting corners or inflating power figures. Now, the market has changed dramatically, and commercial deception is rife. Years ago, a small flagship amplifier costing tens of thousands of yuan was converted into a pure power amplifier. With 60W x 3 and 22W x 4, using an HTPC and D2, it powered seven large speakers with great success! Even without a subwoofer, I could still feel a strong throbbing sensation. Meanwhile, today, on so many audio forums, the constant talk is about "not being able to power the speakers." Many manufacturers boast of 100-200W x 7, yet still claim they can't power the speakers. This frustrates me and I find it incomprehensible. I won't analyze why manufacturers do this; amplifier power amplifiers simply use a lot of copper and aluminum! Anyone of a certain age knows that copper and aluminum used to be only slightly more expensive than iron, but were considered inexpensive. Ordinary people had copper utensils everywhere. But what about today?

Many people don't fully understand what kind of performance an amplifier should truly achieve, mistakenly believing that sufficient power is all that matters. They also have no idea what the difference is between an integrated amplifier's power stage and a pure power stage. They constantly talk about "control" and "resolution," but have no idea how an amplifier can achieve these qualities.

A friend once consulted me about a 2-channel pure power amplifier. I brought up the two extremely critical but less familiar concepts of "damping coefficient" and "conversion rate".

Basic indicators of power amplifier: rated power.

Nowadays, amplifiers in the US and Europe are labeled with rated power. Older amplifiers also used this method. This refers to the power output at minimal distortion (e.g., 0.015% at 20-20kHz; more advanced amplifiers use 0.008%). To achieve strong output power, a powerful power supply is absolutely essential! The power level reflects the strength of the sound, or the perceived volume.

The second basic indicator of a power amplifier: various distortion levels.

As mentioned above, this is directly related to the power level. When the power of the amplifier is large enough and only a small part of it is used, the distortion will be much smaller.

Integrated amplifiers often use just a pair of power tubes in their power stages. This pairing significantly impacts distortion. High-end amplifiers used to be paired directly on the production line (for example, older amplifiers had very low distortion; a 10,000 yuan unit back then would be equivalent to a 100,000 yuan unit today). This was very costly, and today's amplifiers costing under tens of thousands of yuan wouldn't be paired this way. With poor power tube pairing these days, it's even more important to use low power at high power levels to minimize distortion. Distortion reflects the quality of the sound, or rather, its texture.

An important indicator only available in high-end power amplifiers: damping coefficient.

Besides power and distortion, a high-end amplifier's output internal impedance significantly impacts its ability to control bass quality. Ensuring low output impedance under high-current conditions requires a high-quality, high-power transformer, a high-current rectifier circuit, and powerful capacitor filtering. Even the most advanced integrated amplifiers lack these features due to space and cost constraints. Pure power amplifiers, on the other hand, offer several times the performance of integrated amplifiers in this regard. Furthermore, to achieve high output power and minimal transistor output impedance, pure power amplifiers utilize multiple pairs of power transistors in parallel, resulting in several times greater controllability than integrated amplifiers, which utilize only a single pair of output power transistors (just imagine how many pairs of power transistors can fit into such a small heat sink).

Of course, the thickness of the speaker wire, the copper content and the quality of the terminal also have a direct impact on the damping coefficient. The damping coefficient reflects the quality of the amplifier's control over the bass, that is, the control force.