Solid State Power Amp Reviews

The bass guitar and kickdrum were reproduced with appropriate force and definition, though I felt I needed to remove the plugs from the Minos' upper ports to optimize the system's low-frequency reproduction. Mark Knopfler's vocalizing sounded clean and appropriately husky. But what really enthralled me about this atmospheric track was the depth of the soundstage. Some of the instruments had been mixed with various amounts of reverb. The piano that accompanies the acoustic guitar at the beginning before the verse, for example, was set way back in the soundstage, behind the voice and marimba. The tunnel of reverb behind the guitar power chords in the interlude stretched way back behind the speakers. The Parasounds nicely separated the soundstage's layers.

It is superb stereo productions like this that make me resistant to the "Back to Mono" movement—for me, space is the place! When producer Erick Lichte and I worked on this issue's Recording of the Month, Translations, performed by the Portland State Chamber Choir conducted by Ethan Sperry (16/44.1k FLAC files, Naxos 8.574124), we worked carefully to arrange the spatial elements of the performance to conform with composer Eriks Ešenvalds' intentions as indicated in the works' scores. With the Parasound driving not just the big Vimbergs but also the little KEFs, the various percussion instruments on track five, Vineta, which tells the tale of a city consumed by the Baltic Sea because of its citizens' hedonistic tendencies, were all precisely and stably positioned in space exactly where we had intended. The vibes at the beginning and the syncopated tubular bells at regular intervals, in particular, could be readily heard lighting up the vast acoustic of St. Mary's Catholic Church in Mount Angel, Oregon.

The Parasound's high frequencies sounded more like what I experience from a good tube amplifier. Even with a recording having a somewhat forward balance, like Christian Tetzlaff performing the Beethoven Violin Concerto with Robin Ticciati conducting the Deutsches Symphonie-Orchester Berlin (24/48k FLAC, Ondine 1334), the Halo JC 1+ amplifiers neatly stepped out of the way of the music-making. (I have been a fan of Christian Tetzlaff since downloading his idiosyncratic recordings of the Brahms violin sonatas with pianist Lars Vogt—DSD128 files, Ondine ODE1284-2D/HDtracks). The Beethoven orchestra was reproduced with excellent depth, especially with the woodwinds, and the image of the violin was both stable and palpable. The manner in which the interplay between the solo violin and the timps in the first movement's cadenza was laid bare by the Parasounds and KEFs was gripping, yet without any feeling that the instruments were unnaturally spotlit.

Dynamics were, as you would expect from such a powerful amplifier, extraordinary. My long-term test track for dynamics is a recommendation from Erick Lichte, "Fit Song," from Cornelius's Sensuous: la musique de 21° siècle (ALAC files ripped from CD, Warner Japan EVE016). The drum samples on "Fit Song" were very cleanly recorded, and I could play them at ridiculously loud levels on the Vimberg speakers without there being any sense of strain. The drums remained behind the plane of the speakers where the synth and voice samples resided, despite the loudness. And while the bass drum crescendos on "Vineta" thundered out of the Vimbergs with the Parasounds, the slight amount of flanging on the bass guitar in Joan Armatrading's "Willow" (16/44.1k FLAC, Tidal) was a model of clarity. Low-frequency power and delicacy!

It was time to see how the new amplifier compared with the original JC 1s: No 38-year-old memories this time. Off I went to my storage space.

Compared with the Halo JC 1
Playing the old JC 1s driving the Vimberg speakers with the level matched with the 1kHz warble tone on Stereophile's Editor's Choice CD to what I had used to audition the new JC 1+s, it all got a little smaller. There was still plenty of low-frequency slam on the Cornelius track, still plenty of soundstage depth on "Vineta," still precise stereo imaging, and a tonal balance that was very similar to that of the new amplifier. But all a little smaller. While Joan Armatrading's haunting voice had the same slightly spitchy quality it had with the new amplifiers—that quality is characteristic of the recording, not the amplifiers—she was presented a touch more forward in the soundstage. The reverb tails of the damped tom-toms that punctate the song's chorus were shorter than I had gotten used to with the JC 1+s.

I followed Joan's "Willow" with Robert Silverman's performance of Schubert's six Moments Musicaux for piano (D.780) from Concert (CD, Stereophile STPH005-2). I had captured this album with a spaced pair of DPA 4006 microphones, so the stereo image is not as precise as is usually the case with my recordings. Even so, with the JC 1+ amplifiers, the feeling of listening to a Steinway D in a real space was very satisfying. And when a member of the audience makes a sound at the back of the hall halfway through the sixth Moment, a sound at the very back of the soundstage is what I heard. Changing to the JC 1s, while the piano's left-hand register still had good low-frequency weight, the image of the piano was closer, the hall a touch smaller, that audience noise slightly less palpable.

While I could live with the JC 1s, and have done so at times over the years, the sound of the new amplifiers had an oh-so-important edge.

Compared with the Lamm M1.2 Reference
At $33,990/pair and offering 95W or 180W into 8 ohms, depending on its output-stage bias setting, this monoblock is more expensive and less powerful than the Parasound Halo JC 1+. But like the Parasound, it is heavily biased into partial class-A operation and its distortion is both very low and predominantly the subjectively innocuous second harmonic. The M1.2s have been in and out of my system since I reviewed them in April 2012. (At regular intervals I offer to return the amplifiers but, like Richard Schram, Vladimir Lamm continues to be okay with the long-term loan.) In my original review, I wrote that as well as the M1.2s being soundstaging champs, there was almost a "glow" to their sound that particularly enhanced mono recordings. Jim Austin basically agreed with me in December 2016: He wrote, "The Lamms didn't bring out every tiny nuance—a surprise, as I expect amps costing this much to do everything perfectly—but boy, are they musical!"

Over the years, while I remain impressed by the Lamms' soundstaging, that glow appears to be accompanied by a somewhat forward balance. Although the M1.2's gain was only a couple of dB higher than the Parasound's, with a high-sensitivity speaker like the Vimberg Mino, I can hear a slight hiss with my ear close to the tweeter, perhaps because I am still using the original input-stage tubes.

Hiss there was none when I changed from the Lamms to the Parasounds. The soundstage remained deep and detailed, but everything within that stage moved a little farther back, with an increased delicacy to the sounds of individual acoustic objects. The M1.2's midrange was a bit more robust-sounding with both the Silverman and Armatrading tracks. Its low frequencies were richer than those of the Halo JC 1+; the Curl-designed amplifier exerted tighter control in the bass with the kickdrum on "Fit Song," which is why I unblocked the Minos' upper ports.

A close-run thing, for sure. With both the big Vimbergs and the little KEFs, I slightly preferred the presentation of the Parasounds on rock and jazz, that of the Lamms on piano and orchestral music.

Summing up
Michael Fremer concluded his review of the original Halo JC 1 by saying "There was nothing solid-state-sounding about the JC 1. . . . There was an honesty to the overall tonal and harmonic presentation that transcended technological stereotypes. Powerful, refined, smooth, organized, dynamic, transparent, and rhythmically supple, the JC 1 offered a combination of attributes that added up to many weeks of listening pleasure."

After several weeks auditioning the Parasound Halo JC 1+ monoblocks, I don't really have anything to add to what Mikey wrote in 2003, other than to note that even with its significant increase in price, the improvement in its sound quality and the explosion in recent years in the prices of high-end, high-power amplifiers keep the JC 1+ competitive. This is a superb-sounding amplifier that will get the best from every loudspeaker with which it is partnered. Well done, Mr. Curl.