The observations behind this article have been taking shape for a long time. The immediate reason for publishing it was a recent comparison with the PROst A7 power amplifier.
By a twist of fate, an Accuphase P-260 power amplifier found its way into my laboratory. Like the A7, it uses lateral MOSFETs in its output stage. However, the design philosophy behind their implementation is fundamentally different, which made the comparison particularly interesting.
The engineers at Accuphase created an excellent amplifier—technically refined and impeccably executed. In many respects, it represents what roughly 95% of all power amplifiers are today: well-designed, competently engineered, and carefully built.
But this raises a fundamental question: is laboratory-grade precision really what music needs? Or is there something else — a missing link between the precision of electronics and the magic of musical instruments?
I answered that question for myself a long time ago.
The A7 was created around that answer. It delivers an extraordinary sense of fluidity and continuity, yet without the slightest hint of softness, blur, or loss of focus. If the performer or producer intended absolute articulation, a sharp, coherent attack, and clearly defined reverberation, that is exactly what you will hear.
The natural integrity of the sonic image is not merely a poetic metaphor when describing the A7. The incidental sounds that belong to the instrument, reverberation, and overtones never become detached from the fundamental note—not in level, not in time, and not in space.
Unlike the A7, almost all conventional amplifiers exhibit an aggressive, forward high-bass and mid-bass character that masks much of the first octave and part of the second. With the A7, by contrast, the entire available range of deep, agile bass is revealed—without excessive emphasis or tonal imbalance. What is particularly remarkable is that this characteristic remains consistent across different listening rooms and with a wide variety of loudspeakers.
It was precisely against the backdrop of the Accuphase’s genuinely excellent performance that these differences became especially apparent.
There is one more aspect that deserves to be mentioned. It has little to do with measurements, yet it may be the most important of all. The A7 is not an amplifier for background listening. No—your attention will be drawn entirely into the music. Or, just as likely, you may reject it altogether. If the recording is poor, the A7 will tell you so without any sugar-coating. More than a dozen of these amplifiers have long been in daily use in recording studios, and their open, highly revealing yet non-fatiguing sound is exactly why.
I use the A7 alongside two other amplifiers as a reference for evaluating the sonic coloration of studio equipment. It reveals more contrasts, nuances, and distinctive characteristics, yet it never allows technical analysis to overshadow the musical narrative.
There is, however, another side to the story. The power consumption is relatively high, and a warm-up period of 15–20 minutes is essential. In addition, you will almost inevitably find yourself listening at higher volume levels. It is comfortable, and it leaves a strong emotional impression.
But yes — it is loud!