Solid State Power Amp Reviews

Onward
I thought the POWERa monos sounded mighty fine powered by the Stromtank, sounding best when their power conditioning was turned off, but I was also aware that current limitations imposed by the S 2500 Quantum MKII might squash dynamics. Not that I expected to use anywhere near each monoblocks' 3600W into 4 ohms in my 16' × 20' × 9.25' listening room.

With wall power, the POWERa monoblocks sounded best with their internal power conditioning engaged. It's not that they didn't sound quite good without power conditioning—my wall power provides far smoother sound than it did before the wire upgrade, and bass is tighter. Nonetheless, engaging power conditioning made the sound even smoother, the noisefloor lower, the top-to-bottom focus tighter. The POWERa's internal power conditioning allowed the inner glow of instruments and voices to emerge with no sense of dynamic constraint.

I reserved the double bank of dedicated duplex outlets for the POWERa's, plugged the Stromtank (which continued to feed front-end components) into one of the other outlets, and used the Acoustic Revive RTP-6 to power several other products. This was as close to my usual power setup as I could get.

The discovery
My first listen came within an hour of installation, before power cables had settled in and wiring changes were complete. Setup was less than ideal, with no attention paid to whether the internal power conditioners were on or off. Nonetheless, my first impression proved accurate.

The sound was as natural as I've come to expect from D'Agostino, Audio Research, VTL, and a host of other top-flight companies that specialize in amplification, if perhaps a little closer to neutral than some—but there was something that set them apart. "These amps give me more of everything I value from the D'Agostino Progression M550s," I thought. "There's greater color saturation, more presence, and stronger bass. There's more there there."

As I got my power act together and fine-tuned the system (as I always do, as a matter of course), the POWERa monoblocks surpassed that initial assessment. By a lot. I queued up an old standby, Yello's "Electrified II" from Toy (24/48 MQA, Polydor 0602547879851/Tidal). Whoa! Even more than the soundstage, which covered the width of the room and extended far up, what stood out was the strength and solidity of deep bass—and beyond. Everything from the pounding beat to Dieter Meier's recitation and Malia's vocals seemed to have greater presence. For visceral impact, swiftness of attack, and sheer, apparent accuracy, the POWERa monoblocks top every other monoblock, stereo amp, or integrated I've reviewed (footnote 7). Ditto for color saturation, shading, dynamics, and the ability to portray the most complex passages without a hint of compression.

Another, far more system-trying test of bass is the second movement explosion in Shostakovich's Symphony No.11 as performed by Andris Nelsons and the Boston Symphony Orchestra on their award-winning live recording, Shostakovich: Symphonies Nos. 4 & 11 "The Year 1905" (24/96 MQA, DG/Tidal). I've heard this recording on many systems, including those with speakers far bigger than the Wilson Alexia V's. But never have I heard a huge bass drum portrayed with such convincing realism: The virtually instantaneous transition from the initial sharp attack to the forceful resonance and decay; the size and weight of the sound; and the depth of emotional impact felt true to the source.

I cannot recall when I've heard this 11th's churning conveyed so clearly, so musically, with so much devastation. To repeat descriptors already invoked, the sheer presence and weight of the sounds, along with the degree of resolution, consistently brought me closer to the live symphonic experience than anything else I've heard (footnote 8).

This "presence" was not limited to large-scale works. Listening to the deeply moving second movement of Franz Schubert's Piano Trio No.2, on the recording Schubert: Chamber Works with cellist Tanya Tetzlaff, her violinist brother Christian Tetzlaff, and the late pianist Lars Vogt (24/96 WAV, Ondine 1394), I was struck as much by the cello's rich, haunting eloquence as by the piano's poetry. Dynamics were tremendous, and Schubert's mix of pain, resignation, and affirmation was more shattering than I have heard it (footnote 9).

Never before had recordings of the marvelous mezzo-soprano Marianne Crebassa displayed such convincing warmth, so much fullness in the core of her voice. (I listened to several of her albums.) Never had soprano Julia Bullock sounded so soulful, so rooted in her open heart, as on her performance of "Brown Baby" from her treasurable album Walking in the Dark (24/192 WAV, Nonesuch 695267).

It may seem strange to cite a mono recording from 1952 in a review like this, but I found myself turning to contralto Kathleen Ferrier's recording of Ralph Vaughan Williams's "Silent Noon," made with pianist Frederick Stone at the BBC Broadcasting House on June 5, 1952—one of many high points in the 10-CD remastered Kathleen Ferrier Edition (16/44.1 FLAC, Decca/Qobuz).

Ferrier's performance of this song stands apart from all others. The metronome imposes no restraints on her treatment of Dante Gabriel Rossetti's lyrics. "Your hands lie open in the long fresh grass," she sings with rapt stillness. After intoning the words "'Tis visible silence, still as the hour-glass" as though they were the holiest of revelations, she pauses. Universes of meaning, the wisdom of the ages, the confessions of countless lovers—all resonate in that silence.

She continues. "Oh! Clasp we to our hearts, for deathless dower / This close-companioned inarticulate hour / When twofold silence was the song of love." It is impossible to listen to this great performance without sensing that Ferrier, who was mortally ill, must have realized she had limited time left to share her gifts.

I've listened to this recording countless times, in various remasterings. In every instance, the limitations of the fuzzy transfer, which apparently derives from early pressings with groove noise and occasional high-pitched ticks, left me feeling bereft at what had been lost from the original recording. To my astonishment, the POWERa monos brought newfound clarity to Ferrier's singing and conveyed all of its magic.

As I discovered how much sound and pleasure the Karan Acoustics POWERa monos could deliver, I found myself going back in time to some of the greatest vocal recordings I've been privileged to hear. Some readers may think someone crazy to spend $106,000 to better extract information buried in old mono recordings, but those who value great art will sense the gifts these monoblocks can deliver. They may delight even more when I recount that playing Ferrier's recording of Hubert Parry's "Love is a Bable" from the same broadcast session brought out her restrained, oh-so-English humor to a greater extent than I ever thought possible. The POWERa laughs, cries, longs, and loves with equal honesty.

Other kinds of music? The John Coltrane Quartet's "Nancy (with the Laughing Face)," from Ballads (24/96 MQA, Impulse!/Tidal), sounded gorgeous, Coltrane's tone warm, round, and smooth, even when he moves fast between notes. James Blake's "There's a Limit to Your Love," from his eponymous album (16/44.1, Polydor/Qobuz), may be well known amongst audiophiles—I play it often, and the bass never sounded more convincing than with the POWERa's—but I often treat it as a throwaway cut: Check out the bass and begone. This time, I found the sound so interesting that I listened all the way through.

A shout out to the immersive deep bass on Ryuichi Sakamoto's "20210310," from 12 (24/96 FLAC, Milan Qobuz), which sounds fabulous through the POWERa's. So do the distinct colors of original instruments on the Chiaroscuro Quartet's recent recording Mozart: The Prussian Quartets (24/96 WAV, BIS 7318599925585). I listened to this recording carefully when I reviewed it a few months back, but it never displayed colors as convincing, distinct, and realistic as through the POWERa's.

Returning to voices: If you want to hear how a great singer projects radiant sounds high in their range, go no farther than soprano Elisabeth Schumann's 1934 recording of Josef Strauss's "Sphären-Klänge" (Music of the Spheres), from the invaluable ICON box set, Silver Thread of Song (16/44.1 FLAC, Warner Classics/Qobuz), where the POWERa's convey her infectious joy, glowingly sweet, disembodied high notes, and boundless personality like no other amps I've heard.

I said goodbye to the Karan Acoustics POWERa monoblocks with two selections: Julia Bullock's heart-opening rendition of Connie Converse's "One by One" and the Chiaroscuro Quartet's performance of the sublime Larghetto from Mozart's String Quartet No.22 in B flat major, K. 589. Both were heavenly. I sat, transfixed.

The not-really rival
In recent amplifier reviews, I've often omitted direct comparisons due to major price discrepancies. Here, such discrepancies are unavoidable, but I'll make a comparison anyway. My reference D'Agostino Progression M550 mono—the least expensive monoblock in the D'Agostino line—cost less than half the Karan POWERa monoblock's considerable price. Nothing in the D'Agostino line, short of the top-level Relentless Epic 1600 Mono Amplifier (even more expensive at $349,500/pair, rated at 3000W into 4 ohms), can come close to matching the POWERa's output (footnote 10).

Power for its own sake means little, however; what matters is the ability to harness power to achieve higher musical ends. Here is where the POWERa excels. Even without amp stands or a silent battery power source, the POWERa outperformed the Progression M550 in my system. More transparency, more resolution, more midrange and low-end weight and substance, more color saturation—the ability to harness power to reach deeper into the musical fabric and extract emotional truth—more and better are the bywords of the POWERa.

The clincher
The Karan Acoustics POWERa monoblocks are big, heavy, extremely powerful, and extremely expensive. Yet, thanks to their sliding-bias class-A design, they will likely not tax your power grid every time you turn them on.

What they give you in return for your investment, in the context of a similarly high-achieving system—I should say, what they've given me—is sound that has taken me closer to the transformative visceral, emotional, mental, and spiritual impact of great artists performing great music than anything I've heard in my system previously. The Karan is a phenomenal achievement, a benchmark for what can be achieved, at least in my modestly sized listening room. If you treasure greatness in audio reproduction and have the means to purchase a pair, seek them out. If you do not have the means, be careful: I, for one, do not wish to get their sound out of my head.

---

Footnote 7: To the naysayers and cynics who think, "Oh sure. Serinus sees the POWERa price tag and how much it weighs and immediately proclaims it 'the best,' I respond: If you have the means to visit a Karan dealer or audition these monoblocks at a show at which setup constraints do not compromise sound quality, please go and listen for yourself. I fully expect you to discover that the POWERa deserves the accolades.

Footnote 8: I've heard the BSO under Nelsons perform Shostakovich live at Philharmonie de Paris.

Footnote 9: Admittedly this is a new recording, so I haven't heard it on very many systems—but I did hear it with the very different sounding Esoteric Grandioso M1X monos, which I reviewed in the April issue.

Footnote 10: I have not heard any D'Agostino Relentless product in my system.