2014 Product of the Year Awards: Solid-State Power Amps

Equipment report
Solid-state power amplifiers
Constellation Mono 1.0,
Constellation Stereo 1.0,
Odyssey Audio Stratos,
Pass Laboratories Xs 300,
Rotel RB-1552 Mk II
2014 Product of the Year Awards: Solid-State Power Amps


Rotel RB-1552 Mk II Power Amplifier

The RB-1552 Mk II is a handsome, purposeful 120Wpc Class AB stereo power amplifier that bristles with the holistic design and careful parts selection that have distinguished Rotel’s best amps through the ages. The unit is essentially a dual-monoblock design and accepts both single-ended and balanced connections (the balanced sound way better). For those whose speakers require a little more oomph, such as Maggie owners, Rotel makes a more powerful ($600 more expensive) 200Wpc version, the RB-1582 Mk II. Modestly priced audio products may not be able to produce the “absolute sound,” but the best of them can fully deliver the heart of the high end. Rotel’s RB-1552 Mk II falls decisively into this category. Through the RB-1552 Mk II, strings are properly rich, bass is weighty, and the piano possesses a lovely round tone. Microdynamics and tiny tempo variations come through clearly, too, allowing the listener to hear the give-and-take between players. The amp also delivers robust dynamics, a broad soundstage, well-placed images, and infectious timing. Another Rotel winner.


Odyssey Audio Stratos

This phenomenal sounding and reasonably priced 180W monoblock from Klaus Bunge of Odyssey Audio uses the same circuit as Symphonic Line of Germany’s $14k RG 11 Mk 4 amplifier (which Bunge also imports). Although the boards and parts in the Stratos aren’t the same premium-quality you get from Symphonic Line, and Odyssey’s anodized-aluminum enclosures, though handsome and well-built, aren’t nearly as deluxe, the sound remains extraordinary. In direct comparison with the best amplifier JV has heard—the $65k Soulution 711—the Stratos monoblocks more than held their own. No, they won’t give you the same levels of speed, resolution, color, bass authority, and dynamic range that the Swiss amp does, but they come darn close with truly exceptional resolution in the bottom octaves. Yes, you can do better than the Stratos monos if you spend a whole lot more. The question you will ask yourself, once you’ve heard them, is: “Do I really want to?”


Constellation Stereo 1.0 and Mono 1.0
$10,000; $20,000 per pair

Featuring the identical circuit topology of the $140,000-per-pair Hercules, Constellation Audio’s new Stereo 1.0 stereo amplifier and Mono 1.0 monoblocks from the Inspiration Series bring more than a taste of the flagship amplifier’s magic to a much more accessible price. Constellation had already developed the reference-grade circuit topology, so why not make that proven design more affordable through less elaborate implementations? The Stereo 1.0 delivers 200Wpc into 8 ohms, and can double its output into 4 ohms. The Mono 1.0 has 400W on tap (800W into 4 ohms). Despite the much lower price compared with the $24k Centaur stereo amp, these new amps sport nearly the same upscale vibe through their similar metalwork and operation. Both Inspiration Series amplifiers exhibit the soundstage transparency, resolution, timbral beauty, and treble delicacy of their more expensive antecedents, but also add a newfound bottom-end weight, warmth, and dynamic impact. This is trickle-down engineering at its best.


Pass Xs 300

Though reviewer Anthony H. Cordesman has expressed reasonable doubts in the past about the value-per-dollar quotient of ultra-expensive high-end gear, he showed no hesitation in calling Pass Audio’s top-of-the-line Xs 300 monoblocks and their companion Xs preamplifier “the two best-sounding examples of a preamp and power I have yet heard.” These 168-pound powerhouse monoblocks deliver 300 watts into 8 ohms, and 600 into 4, with 48 amps of peak current. The increase in power (over AHC’s previous references, the Pass XA-160.5s) makes a difference in apparent musical “speed” and detail in big dynamic moments. Capable of delivering immense amounts of power and energy down to the deepest bass, the Xs 300 is not only AHC’s pick for top amp; it is also TAS’ Cost-No-Object Amplifier of the Year.