Solid State Power Amp Reviews

For those who've never experienced them, I should point out that, with every compatible amplifier I've tried, the Magnepan .7 loudspeakers produce notes, tones, massed strings, drum whacks, and ringing bells all with slightly rounded leading edges. They get the shimmer of tones extremely well, but not the initial bite. For decades, that slight, almost subliminal rounding has been the bête noir of the Magnepan sound. Let me explain.

On a dark, reverberant recording like Anouar Brahem's Blue Maqams (24/96 FLAC ECM/Tidal), the .7s round each note's front edge as described above, but then they let the body and tone of the note blossom fully. Finally, they let the note's decay merge pleasurably into a shimmering dark space. The Primare A35.2 amp, driven by the Rogue RP-7 preamp, sourced by the Chord Qutest digital converter playing Tidal, played the .7s exactly as I just described—except! It added a terse, plucky solidity to the whole note, mitigating the Maggie's leading-edge deficiencies. Suddenly, the Maggies had bite—and I was digging it. On Blue Maqams, the A35.2 gripped the Magnepans' diaphragms with greater control and force than either the class-A Pass Labs XA25 ($4900) or the $3495 all-tube, class-AB Rogue Stereo 100 (in Ultralinear mode). This control delivered a tauter, more rhythmic bass. I thought to myself, This amp and speaker have a future together!

A class-D comparison: Primare vs Bel Canto
Starting in 1959, before the full impact of television, folk song archivist Alan Lomax used a stereo microphone and a two-track Ampex recorder to capture a view of the minds and musical cultures of African-Americans in the rural south. Southern Journey Volume 13: Earliest Times (Rounder CD 1713) has 21 songs from John Davis, Joe Armstrong, Henry Morrison, and the legendary Bessie Jones, whom Lomax called "The Mother Courage of American Black traditions." Alan Lomax recorded Bessie Jones and the Georgia Sea Island Singers in the one-room Harrington School on Saint Simons Island, and the sound on the songs "Union" and "East Coast Line" puts a life-sized Bessie solidly behind the Magnepan panels with the Sea Island Singers lined up behind her. The Primare A35.2 + Magnepan .7s nailed the positioning of the performers and the simple clarity of Lomax's recording technique. But compared to the previous 100 times I've listened to these songs, the presentation seemed distinctly austere. The singers' mouths seemed dry. The cushion of bare-walled room air seemed mostly absent, the performances less engaging than I remember.

I then decided to see how the class-D Bel Canto REF600M mono amplifiers ($4990/pair) would handle the same program. Unfortunately, when I substituted the Bel Canto monoblocks, they sounded slightly off their usual cool'n'fast game. Then I remembered: The REF600Ms, like the Pass Labs XA25, take around two full days to relax, get colorful, and reproduce nuance. Therefore, I had to listen and wait. While I waited, I played a variety of musical genres, and on the third day began wondering if both amps might sound the same.

After four days, I played Bessie Jones and the Sea Island Singers, and dang, their voices sounded vivid but a touch dry and austere—just like with the Primare A35.2. Then I returned to Primare and . . . damn!

I became concerned, because I had never before experienced two amps playing the same songs on the same speaker and being indistinguishable from each other.

With Harbeth monitors
Seeking a more monitor-like resolution, I ditched the Maggies and stuck in my Number One reference speakers, the Harbeth M30.2s, which in my house play their best with the 100W Rogue Stereo 100 amplifier.

After loosening up the M30.2s for a day, I became concerned once again: On a variety of musical programs, the Primare and Bel Canto still sounded the same. Both did bass punch and detail. Both presented upper-bass/lower-midrange with perfect clarity and a slight warmth. The only difference I thought I could discern was in the high frequencies, where the Bel Canto seemed a teensy bit more natural. Maybe.

Another class-D comparison: Primare vs Mytek Next, with the Harbeths, I tried the $2495 Mytek Brooklyn class-D amplifier. The Brooklyn is a stereo amplifier in a very small (8.5" × 9.5" × 1.74") chassis. The amplifier uses Mytek-modified class-D modules (sourced from Danish company Pascal A/S) to generate 250Wpc into 8 ohms and 300Wpc into 4 ohms.

I listened first to Debussy: Préludes du 1er Livre—Estampes, performed by Javier Perianes (24/96 FLAC Harmonia Mundi/Qobuz). Compared to the A35.2, the piano sound was warmer and richer with the Mytek. The Mytek made the Primare sound stark. In return, the Primare made the Mytek sound soft and dark.

Next, I listened to David Byrne's "I Dance Like This" from American Utopia (24/96 FLAC Nonesuch/Qobuz). The composition features Byrne's vocals over heavy synth-bass and drum-machine tracks: "We dance like this because it feels so damn good . . ." The song's composition is almost crude in its jarring pop simplicity, and on most systems it sounds muddy and overprocessed; it takes a serious hi-fi (or good headphones) to sort out the detail of the bass-and-drum tracks. The Primare A35.2 did a better job than the Mytek at making sense of the bass and drum tracks and making Byrne's vocals more intelligible. The A35.2 did all this while adding light to the soundstage. With the M30.2s, the Mytek got the nod on musicality, while the Primare got the prize for punch and clarity.

More comparisons
As of February 7, 2020, my Stereophile reference system consists of the Chord Qutest DAC driving the Rogue RP-7 preamp driving the 100Wpc Rogue Stereo 100 tube amplifier, the 100 in turn powering the Harbeth 30.2 Monitors. To my ears, this system is neither warm nor cool nor hard nor soft nor excessively dark nor bright. It dances pretty well and likes all genres of music. When I replaced the all-tube Stereo 100 with the Primare A35.2, the clarity and impact of the bottom six octaves (50Hz–3.2kHz) increased dramatically. Detail, image outlines, and vocal intelligibility improved moderately. However, the spectrum of midrange color was reduced.

I am still struggling to describe what was happening above about 3.2kHz. With the A35.2 driving the 30.2s, a few recordings sounded confused or slightly distorted above 3.2kHz; on other recordings, these top octaves sounded clear but electronically empty rather than transparent. Think "shape-shifting highs."

My in-house reference for high-quality high-frequency reproduction is the Line Magnetic LM-518 IA integrated amplifier. With every compatible speaker, the Line Magnetic's single-ended 845 tube makes full-bloom, pollen-rich, air-is-fresh high frequencies. The sounds of cymbals and sopranos are crisp, super-clear, and loaded with spiderweb detail. It is luxuriant and engaging. The Primare's high frequencies are also crisp and super-clear—but not luxuriant and engaging.

In sum
My time spent with the Primare A35.2 amplifier reminded me that there still is no such thing as a perfect, one-size-fits-all amplifier. Some amps are stronger or more engaging than others. Some deliver exciting force, while others deliver subtle, enduring charms. Some, like the Primare A35.2, have high-toned manners, can dance the latest dance, and sometimes even order fine wine. Which reminds me: I never actually drank that Château Margaux. But I swear to you, the Primare amplifier looked expensive and sounded ooh la la! with the unopened bottle sitting next to it.