Solid State Power Amp Reviews

While I usually place equipment supports under components, I decided to skip them in this case to avoid damaging a hand as I struggled to lift a corner of the amp while not tipping over the amp stand. After connecting XLR and speaker cables, I ran two Nordost Odin 2 15-amp power cables from the AMP V to the same AudioQuest Niagara 7000 power conditioner I use with the D'Agostinos and began my journey.

Color and richness to the fore
On Igor Levit's On DSCH (24/96 MQA, Sony 714315), which I reviewed for our December issue, the AMP V's ability to convey the emotion behind the keys confirmed its musicality. On the other recording I reviewed for that issue, Florence Price's Symphonies Nos.1 & 3 from the Philadelphia Orchestra under Yannick Nézet-Séguin (24/96 FLAC, DG e-release), the AMP V's way with orchestral color and midrange richness came to the fore. On another Price recording that came out at almost the same time, Naxos's issue of Price's Third Symphony from the ORF Vienna Radio Symphony Orchestra, conducted by John Jeter (24/96 FLAC, Naxos 8559897), the highly resolving AMP V easily revealed that Jeter's recording was set farther back and lacked ultimate clarity.

After a trip to Gig Harbor, Washington, to cover the US unveiling of the new Graham LS8/1 loudspeaker, I returned determined to hear how one of the tracks most frequently played by Philip O'Hanlon during the demo—"Birds" from Nameless (24/88.2 MQA, Ensoul Records/Tidal) by Canadian artist Dominique Fils-Aimé—sounded through the AMP V and bigger speakers. The soundstage was as deep and spacious as could be, double bass sounded strong and fully controlled, and hand claps were believable rather than digitally sharp. On another Fils-Aimé track, "Feeling Good," it was easy to gauge the singer's distance from the microphone. This is an extremely revealing amplifier.

Eager to audition recordings with huge dynamic swings, I asked a few top recording engineers for their favorites. Everything I received was fabulously recorded, but some were far more dynamic than others. (After one engineer warned me of dramatic bursts that could blow out my speakers, my friend Scott and I braced ourselves for the ear-deafening eruption that never came.)

Dynamics or no, I sat stunned as I listened to Tidal's 24/352.8 MQA files of Patricia Barber's album Clique (Impex Records). Barber's triumph was recorded by Jim Anderson in Chicago, mixed by him at Skywalker Sound in Northern California, and mastered by Bob Ludwig in Portland, Maine. What immediately stood out was the pristine silence between the notes. The AMP V is one of the quietest amps I've ever heard. Equally notable was the impressive color saturation, with primary hues and infinite shades of pastel vying for attention with midrange warmth. The first notes I scribbled down were these: "air is tremendous—height cues and depth and soundstage spread super—timbres perfect—huge and spacious—so many subtle soft sounds." What I remember most though was the absolute black silence between notes, which allowed colors and contrasts to shine through (footnote 3).

I reveled in the contrasting timbres of electric guitar and the subtle taps of sticks on the sides of drums. I had never heard the resonance of Barber's piano conveyed so perfectly. Equally impressive—stunning, in fact—was the clarity, weight, and pitch-perfect control of Patrick Mulcahy's bass. I expect that all jazz lovers would take immense pleasure in the way the AMP V differentiates timbres of individual instruments and conveys every subtle variation in color and dynamics. Color and dynamic nuance may be more subtle in jazz than they are on Holst's The Planets, but they're even more crucial.

One recording that never fails to enthrall with the sheer expanse of its soundstage (in all directions), natural color, and surprising dynamics is Eriks Ešenvalds: Translations from the Portland State Chamber Choir under Ethan Sperry (24/96 WAV, Naxos 8574124). On the John Atkinson–engineered title track, "Translation," and the Doug Tourtelot–engineered "The Heavens' Flock," the silences, the weight of the low male voices, and the dynamic contrasts were the best I'd ever heard from my system. Vocal decay in the exceptionally resonant acoustic of Saint Mary's Catholic Church in Mt. Angel, Oregon, was utterly convincing.

Mastering engineer Tom Fine sent me a few excerpts of 24/192 WAV files from the digital remasters he has prepared for the Mercury Living Presence Vinyl Series 1 issues (footnote 4). Of Antal Dorati's famed rendition of Stravinsky's The Firebird with the London Symphony Orchestra, Fine wrote in an email, "This is an example of the dynamic range present in the master tapes. The music goes from a level so low [that it was] just above the threshold of tape hiss to full digital zero"—that is, maximum digital loudness. The AMP V didn't break a sweat. Rather, it left me wishing that I had a larger listening room and even bigger speakers, with sufficient cabinet volume and big enough woofers to begin to convey the full measure of this recording's bass (footnote 5).

What about Holst's The Planets? On Zubin Mehta's 1971 recording with the Los Angeles Philharmonic (24/176.4 FLAC, Decca/Qobuz), I found the sound brash but convincing. The Alexia 2s can produce only so much bass in my room when everything is thrown at them at once. Bass weight is more convincing when a bass drum pounds alone, as on the stunning Reference Recordings version of Copland's Fanfare for the Common Man from Eiji Oue and the Minnesota Orchestra (16/44.1 FLAC, Reference Recordings/Qobuz). Taking those limitations into account, the recording's soundstage expanse and visceral impact were tremendous.

Damped if you do, damped if you don't
I first experimented with the AMP V's damping-factor linearization feature while playing electric bassist Brian Bromberg's "The Saga of Harrison Crabfeathers" from his 2002 album, Wood (24/96, Qobuz, footnote 6). With it engaged, the sound grew warmer, which was not what I expected or desired.

On Clique, I found sound most transparent without damping-factor linearization. With it, the ticks of sticks tapping the edge of drums were a bit toned down, air lessened, and a slight bass halo was added around sounds in the treble range. Barber's voice warmed as the midrange became more prominent and highs toned down a bit; if percussion seemed more impactful, it was only because the highs were softer. I experienced similar bass-and-treble changes on Andris Nelsons and the Boston Symphony Orchestra's superb recording of Shostakovich Symphonies Nos. 4 & 11 (24/96 WAV, Deutsche Grammophon 002859502). On The Planets, I experienced more clarity, albeit with increased sharpness, without damping linearization.

In my system, Damping Control was a mixed bag.

Comparison
For some audiophiles, the D'Agostino Progression M550 monoblocks ($44,900/pair, 1100Wpc into 4 ohms, 115lb each) and the Accustic Arts AMP V ($50,000, 1360Wpc into 4 ohms, 176lb) are in the same price range. The Progressions, though, are D'Agostino's entry-level monoblocks, while the AMP V is Accustic Arts's reference stereo amp.

In my system, the two amplifiers certainly sounded different, to a surprising extent. Before listening, I used the "1kHz at –20dB reference tone" from the Stereophile Editor's Choice CD and a Fluke meter to match levels at the speaker terminals as closely as possible. Then I chose the Brian Bromberg aforementioned track and Anna Thorvaldsdóttir's orchestral blockbuster, Metacosmos, performed by the Iceland Symphony Orchestra on Concurrence (24/352.8 WAV, Sono Luminus DSL-92237). The sound was so different with the two amplifiers that if I hadn't matched levels, I would have thought the volume levels were different (footnote 7). Along with more saturated colors (as in a richer-sounding piano), increased image weight, and superbly controlled bass, the AMP V sounded brighter and brasher than the mellower, warmer Progression M550s. I'm not certain whether the AMP V was truly quieter and more transparent or just seemed so because its more pronounced and etched highs stood out more from the instrumental fabric. It was equally hard to tell if the bass was really stronger or just seemed stronger because every sound on the AMP V was so distinct.

As when I compared the D'Agostino Momentum HD preamplifier ($40,000) to the Esoteric Grandioso C1X preamp ($45,000), I felt here that the Accustic Arts amp was more single-mindedly yang in character and the D'Agostino mono more successful in tempering yin with yang.

After I'd packed up the AMP V and the Progression M550s had fully settled back in, I spent an hour listening to Holst's The Planets, Barber's Clique, and voice and piano recitals by soprano Renée Fleming, mezzo-soprano Susan Graham, and tenor Jonas Kaufmann. I was in heaven. I could happily spend the rest of my life with either amplifier.

Conclusion
Can any single review of audio equipment be definitive, given the differences in listening rooms, equipment configurations, and human sensibility? Perhaps not. Nonetheless, a few things about the AMP V are incontrovertible. It's not just a powerhouse; it's a musical instrument that produces bright colors, huge images, and seat-shaking bass. Nor does it skimp on detail. While I didn't journey into heavy metal during my time with the AMP V—Bromberg, Holst, and Shostakovich on steroids were as close as I got—the AMP V sailed through numerous ultradynamic tracks whose cumulative percussion and brass would leave many a rock fan diving for cover.

The AMP V is one of the finest and most musically satisfying amplifiers ever to enter my audio system. Anyone with a spare $50,000 (and who doesn't require easy portability) would be foolish not to give it a serious audition.

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Footnote 3: An equally striking DXD recording for color and space, recorded and mixed by Anderson and mastered and edited by Ulrike Schwarz, is Min Xiao-Fen's White Lotus.

Footnote 4: Sorry, friends old and new, I can't send you copies.

Footnote 5: With this very hope in mind, I recently bought a Powerball Quick Pick. I missed the winning numbers by five.

Footnote 6: Thank you, Steve Zettel, for this one.

Footnote 7: I double checked. They weren't.