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The SPEC amplifier is an ultra minimalist device. It features only a volume knob and input selector. There's no remote though you can optionally order one which is realized in a quite unconventional way. More on that in the final page. The RSA-V1 comes from a small specialized manufacturer known only to very experienced audiophiles. It is the result of a love for music which you can both see and hear. Its mechanical design combines a heavy metal enclosure with several types of wood. And finally it has a rather distinctive sound as though it had been especially designed to work with my Harbeths. Does that ring bells? How about the Lavardin Technologies IT-15? That review is an important reference point for today's assignment.

Generally speaking these two components appear to sound completely different. Decomposing their sound to a set of prime factors we arrive at a group of often contradictory elements. Yet after assembling it all back together and connecting amps to speakers from the likes of Harbeth or Spendor, we get a comparable musical message evoking similar emotions - although, let’s repeat it once more, by using a set of different tools.

I auditioned the SPEC RSA-V1 in two very different systems – my own and that of the Nautilus audio shop in Krakow, there with an Accuphase DP-510 CD player, Dynaudio Special 25 Signature Edition speakers and Purist Audio Design cables. With these two systems the amplifier sounded quite different. The Dynaudio/Accuphase setup proved that the amplifier delivers an extremely precise and exceptionally pure sound. I also very quickly realized that it seemed not to be limited by power restrictions because not only did it excel at deep dynamic bass but also well-differentiated dynamics. However all along I had the impression that this did not convey a completely coherent message - that all I saw was a frame on which the sound was built but not yet as a complete finished project. This only happened with my Harbeths.

As Mr. Hontai wrote, one of the companies that used SPEC amplifiers during their loudspeakers presentations was Kiso Acoustic. Was it coincidence that their HB-1 speakers garnered two awards from me based on my auditions during the High End 2011 show in Munich: Best Sound High-End 2011 and a Red Fingerprint award? I do not think so. It had been a well though-out system showing in which direction to proceed.

The sound I heard after hooking up the RSA-V1 to my Harbeth M40.1 was nothing short of spectacular. It probably—or almost certainly—was the first class D amplifier I knew where the technology not only failed to prevent it from achieving a high-quality sound but in many ways actually improved it to create such grandeur. With the Dynaudio speakers and Purist wiring I had the impression that it lacked some fullness in the lower midrange and that the upper midrange was a bit too forward. As is well known, class D amplifiers almost always are very sensitive to speaker cables and crossover designs. The latter in fact constitute a part of the reconstructive low-pass filter inside the output section of such amps. That’s perhaps why the amp’s audition at Nautilus floored me to some extent by its sheer power, clarity and precision but was not fully satisfactory. I did not buy into it.

With my Harbeth and Tara Labs speaker cables the Japanese amplifier played a different tune. It showed a beautifully saturated almost warm sound with a very strong solid bass foundation. It might for a moment have seemed that the treble was slightly withdrawn and softened as part of the classic class D trademark sound but after prolonged listening and a subsequent return to the reference system I found this hard to confirm. It was more like a foreboding shadow. Cymbals sounded very very convincing, both rich and full, somewhat ‘tube-like’ as heard from a good 300B amp and thus neither withdrawn nor warm but just right – natural in weight, texture and density.

But one does not immediately perceive cymbals thus because they appear as part of the midrange. And that’s the most impressive sub range of this amplifier not because it is limited to it but rather because the midrange is best differentiated to constitutes a true center from which we get the highest emotions. I mentioned this differentiation not without reason. Both treble (to a lesser extent) and bass (more so) do sound great—it’s hard not to like their color and dynamics—but when it comes to differentiating instruments within their ranges, showing clear textures is not their forté. The midrange though is a completely different story.