Solid State Power Amp Reviews

Regarding the Centaur II 500's reproduction of low frequencies, even when the speaker had relatively limited extension—such as the Dynaudio Special Forty stand-mount I reviewed in September 2018—there was a surprisingly satisfying combination of weight and control. For example, when Jaco Pastorius drops down to a detuned low F and C at the start of "Overture—Cotton Avenue," from Joni Mitchell's Don Juan's Reckless Daughter (AIFF file, 24-bit/192kHz needle drop from LP, Asylum K63003), I didn't feel I was missing too much music with the Dynaudios. (And yes, I know—no one but a reviewer is going to use a $55k amplifier with $3k speakers.) And the dynamics were, as you might expect from a 500Wpc amplifier, superb. The timpani blows before the gong that introduces the coda in the Rachmaninoff's final movement rocked me back in my chair. (This was not with the small Dynaudios, of course, but with Tidal Audio's full-range Akira speakers, which I'll review next month.)

One aspect of the time I spent with the Constellation puzzled me: Its sound varied more than I'm accustomed to. Yes, as Steve Guttenberg wrote in our August issue, it's not uncommon for a system that makes music magic one evening to suffer the blahs the next. Even so, the Centaur II 500 seemed more prone to this phenomenon than the other amplifiers I've been using recently. Which brings me to . . .

Comparisons
The Constellation Performance Centaur II 500 replaced the Lamm Industries M1.2 Reference monoblock amplifiers, which I reviewed in April 2012 and which had proved a synergistic partner to the Wilson speakers. Still, the Wilsons' high sensitivity revealed that the Lamms had become noisier than when I'd reviewed them, perhaps due to their input tubes aging. The Lamms cost $32,490/pair and combine a tubed front end with a conventional push-pull MOSFET output stage to produce a maximum output of 110W into 8 ohms. The Lamms are almost 6dB more sensitive than the Constellation, so when comparing the amplifiers I took care to match their levels to within 0.1dB, using the volume control of my PS Audio PerfectWave DirectStream DAC.

The Lamms had a more robust, less delicate sound than the Constellation. In "Overture—Cotton Avenue," Joni Mitchell's voice projected slightly more to the front of the soundstage, and had a little more richness in the midrange. In the Rachmaninoff symphony, the Constellation had a bit more top-octave "air" around instruments, but rather less bloom in the upper bass. With the rolled bass-drum figure at the end of the Rachmaninoff's final movement, the Performance Centaur II 500 definitely had a tighter grip on the woofers than did the M1.2s. When it came to imaging, though I'd always found the Lamm monoblocks to be imaging champs, the two-channel Constellation threw a little more soundstage depth.

For example: At the start of the second movement of the San Francisco Symphony Orchestra's recording of Beethoven's Symphony 7, conducted by Michael Tilson Thomas (24/96 ALAC, SFS Media), the violas, cellos, and double basses introduce the riff that underlies the movement. With the Lamms, the images of the groups of instruments are apparent, but the violas blend into the cellos a little; with the Constellation, the view into the soundstage was a little more clear, and more of the hall acoustic was audible.

The Bricasti Design M15 power amplifier, which Jason Victor Serinus reviewed in July 2018, was still around when I received the Constellation, so I spent a weekend comparing the two amps with the Wilson speakers, again with levels matched. The M15 costs $18,000, has a push-pull output stage using bipolar transistors, and offers 125Wpc into 8 ohms. The Bricasti's low frequencies had a bit too much bloom compared with the Lamms, and even more in comparison with the Constellation, though the richness the M15 added to the cellos and double basses in the San Francisco Symphony's recording of Beethoven's Symphony 7 was enjoyable.

The M15's top octaves were very smooth—the violins in the Beethoven sounded a little sweeter than through the Centaur II 500—but again, the Constellation amplifier presented a cleaner view into the recorded soundstage. If the Bricasti's sonic signature is reminiscent of the Mark Levinson amplifiers of the 1990s—mellow, with a big bass, but somewhat lacking in pace, rhythm, and timing (footnote 2)—the Constellation's was more like the Krells of that era: clean, clear, with superb low-frequency control.

My new torture track for revealing any problems a product might have dealing with low frequencies at high powers is "#thatpower," featuring Justin Bieber, from Will.i.am's #willpower (16/44.1 FLAC MQA, Interscope). The Bricasti reproduced the sampled kick drum with more upper bass than did the Lamms or the Constellation. Peak levels reached 98.6dB (measured with the Studio Six Digital SPL Meter app on my iPhone 6S, with C weighting and slow ballistics). When, on the line "I'll take you higher," the bass line drops to the subdominant, the Centaur II 500 sounded a little less "phatt" than the M1.2s, and even less so than the M15, to the benefit of the music's clarity. The sampled snare drum in this track inherently sounds coarse, but the Centaur II 500 had less of a cack-cack quality than either the Bricasti or the Lamms. Winner on points? The Constellation.

Conclusions
Constellation Audio's Performance Centaur II 500 is one of the best-sounding amplifiers I have auditioned in my system. It offers high power, excellent low-frequency control, and clean, clear high frequencies. The accuracy and stability of its stereo imaging are to die for, coupled with a superbly transparent view into the soundstage.

And it is very expensive. I fear I must leave it to you, dear reader, to decide if it is too expensive.

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Footnote 2: I will never forget visiting UK reviewer Martin Colloms in the early 1990s. Like me, he was using Wilson WATT3 speakers and Puppy2 woofers. However, while I had a Mark Levinson No.23.5 amplifier at that time, Martin was using, if I remember correctly, all Naim amplification. While my system was optimized for soundstage reproduction at the expense of rather lazy low frequencies, such was the sense of drive from Martin's system that it had me groping for my asthma inhaler!