JMF HQS 7001 monoblock power amplifier Page 2

The rear panel is dominated by large, vertical heatsink fins. To their left, top-to-bottom, are the XLR input, JMF Audio's proprietary gold-plated, 120A-rated, 6mm-diameter LSS output terminals designed for JMF speaker cables, then WBT modular gold-plated output terminals for spades, wire, or 4mm-diameter banana plugs. JMF Audio recommends their own speaker cables, but to keep things as simple as possible, I used my usual cabling. Below the outputs sits a ground connection that may be used to link the loudspeaker's shield to the amplifier's case—I didn't need it—and the connection point for the captive power cord. Everything is positioned quite close together, making cable separation a surmountable challenge.

I placed the HQS 7001s on Grand Prix Monza amp stands with the same Wilson Audio Specialties Pedestal supports I usually use with amplifiers. I plugged the amps directly into my dedicated AC line. All other components were powered by a Stromtank S 2500 Quantum MK II battery-source AC generator.

I took JMF Audio at its word when it recommended allowing its HQS power amplifiers "to warm up for at least four hours at room temperature. For this, the power amplifier should be fully powered on." I left the amps on 24/7.

Time to enjoy
During my first days of listening, I was convinced these amps had a slight sepia finish—that they delivered an entirely satisfying if somewhat toned-down full-range listening experience. Then the sepia finish vanished. In its place, I discovered extremely colorful and neutral sound that made me want to listen more and more. As I type these words on deadline day, I find myself drawn back to the music room for one more listen.

I didn't give the HQS 7001 monos an easy time. Rather than feed them a simple ballad, I challenged them with a recent Recording of the Month that has also become one of my Records to Live For: Shostakovich Symphonies No.2, 3, 12, and 13 performed by the Boston Symphony Orchestra under Andris Nelsons (24/96 WAV, DG 4864965).

Percussion was downright fabulous in the Second Symphony. In the Third and Twelfth, Shostakovich's all-stops assaults of militant optimism were breathtaking. When the Twelfth grew tender and lyrical (albeit not for long), the JMF monos softened with them. And in the monumental Thirteenth, when the magnificent Matthias Goerne gave voice to the rage, sadness, repulsion, irony, stoicism, fear, and resistance transmitted by the five Yevtushenko poems Shostakovich set, the music and sound moved me beyond words. To pull myself back together, I turned to the infinitely beautiful Adagietto from Mahler's Symphony No.5, performed by the Orchestre symphonique de Montréal under Rafael Payare (24/96 FLAC, Pentatone). The sound was gorgeous, warm and filled with color. I enjoyed the presentation's delicacy, grace, and beauty so much that I went on to investigate portions of the symphony's first and final movements. Woodwinds stood out for their warm beauty, and bass was so impressively of a piece that I felt impelled to audition a new percussion recording.

That turned out to be Steven Schick's Soundlines: Weather Systems II (24/96 WAV, Islandia Music Records). As fascinating as Xenakis's percussive tour de force, Psappha, was, and as realistically and convincingly a huge drum resounded with the HQS 7001—I could feel the visceral hits to the drum's head—I found myself wishing that I could locate the even more awesome 24/352.8 rendition of the piece on 2L's Utopias album, which I auditioned over five years ago. That's how vividly aural memory lingers when you get high solely on sound, color, and force. Sticking with Schick, the unique sounds on his rendition of Vivian Fung's The Ice Is Talking intrigued me no end. Sounds of ice cracking and timbral contrasts were totally convincing. Powerful music brought home by powerful amps.

Continuing to heed the call of the untried and unfamiliar, I turned to Lutoslawski's Partita for Violin and Orchestra performed by Christian Tetzlaff and Nicholas Collon on the Finnish Radio Symphony Orchestra's new recording, Witold Lutoslawski: Concerto for Orchestra, Partita for Violin and Orchestra, Novelette (24/96 WAV, Ondine ODE 1444-2). Color saturation was superb, and the sound was open and compelling.

I was on a roll. Time for a journey down memory lane, with two of my longtime soprano favorites: Leontyne Price's radiant rendition of Marc-Antoine Charpentier's "Depuis le jour" from the opera, Louise, recorded at Price's peak in 1965 on her marvelous recital Prima Donna Vol. 1 (16/44.1 MQA, RCA Red Seal/Tidal), and Eileen Farrell and Leonard Bernstein's awe-inspiring Immolation Scene from Wagner's Götterdämmerung, performed by the New York Philharmonic on what sounds like the biggest soundstage in the whole wide world (24/192 FLAC, Columbia/Qobuz).

For days after—a week—I kept hearing the end of the Immolation Scene in my head. I could hardly believe how well these amps captured the maximal openness and volume of Farrell's voice on high. Every inch of the soundstage was consumed by the collapse of Valhalla, Kingdom of the Gods. As Wagner's curious mix of superhuman powers, soap opera intrigue, and hopeless, fatal romanticism crashed and burned on the operatic stage, another God rose in its place: the God of hi-fi.

Time to investigate some other genres. For this task, I welcomed my friend Scott, who picked two very different tracks, Talk Talk's "Life's What You Make It" from The Colour of Spring (24/96 FLAC, Parlophone UK/Qobuz) and The Police's "Spirits in the Material World," from Ghost in the Machine, 2003 remaster (16/44.1 FLAC, Polydor/Qobuz). Both sounded vital.

For one of my last few listens, I asked Fusilier to send a few of the tracks JMF Audio uses to evaluate its electronics. One was Morten Lindberg's recording of the title track from his acoustic jazz album, Polarity (24/352.8 FLAC, 2L-145), with Jan Gunnar Hoff, the Hoff Ensemble, Audun Kleive, and Anders Jormin. This track sounded open and alive; I finished the album and played it again. As with everything else I played, the music sounded so right that questions of slam, speed, color, vibrancy, and so on never crossed my mind.

Given JMF's French provenance, I ended my formal listening with Susan Graham singing Reynaldo Hahn's "À Chloris," from her reputation-defining recital, La Belle Époque (16/44.1 MQA, Erato/Tidal). I was transported back 25 years to the first row of UC Berkeley's Hertz Hall, where I once sat mesmerized by Graham's mezzo as she sang this song. If I am fortunate enough to be surrounded by such beauty as I take my last breath, I will die a lucky man.

I tried to compare resolution and detail between my reference D'Agostino Momentum M400 MxV monoblocks and the JMF HQS 7001s during the extremely complex final three minutes of Payare's Mahler Symphony No.5. I found the two presentations equally satisfying—indeed, equally overwhelming. Air and depth seemed more or less equal. At times I felt that the JMFs delivered more bass; other times, I thought the D'Agostino's bass seemed a mite tighter and tidier.

Which is to say
As I contemplate the monoblocks that have moved me most over the past year or so—the Accuphase A-300, Octave Jubilee Mono SE, Infigo Method 3, Dan D'Agostino Momentum M400 MxV, and the JMF Audio HQS 7001 that is the subject of this review—I realize how unique each of them is. Each has a sound as memorable as Aretha's "Respect," Joni Mitchell's two very different recordings of "Both Sides Now," Dylan's definitive "Like a Rolling Stone," or Lotte Lehmann's irrepressible ecstasy on Wagner's "Dich, teure Halle" and "Du bist der Lenz."

The JMF Audio HQS 7001, however, is especially adept at putting music front and center without injecting commentary. It's not Aretha through Accuphase or Dylan through D'Agostino, as memorable and satisfying as those artistic marriages are; it's Joni front and center with only a microphone between you and her soul. The HQS 7001 is a bit like the fine wine whose bouquet you can't describe other than to say that your meal was divine in part because you sipped it.

If you've got the bucks to make a pair of these amplifiers your own, I urge you to check them out. Compare them with your reference and see if they are right for you. I believe that the more you listen, the more you'll want to listen. The JMF Audio HQS 7001s are that good.

JMF Audio
228 Voie des Chartons
88650 Anould
(310) 975-7099

georgehifi's picture

Nice to see a linear amp review back on deck.

JMF specifies 300W-8ohms, 500W-4 ohms, 850W-2 ohms (this says to me bi-polar)

JA measurements: 310W-8ohm, 515W-4ohm, 760W-2 ohms (this suggest mosfet taking an almost 100w dive into 2ohms, regardless of just 3vac line drop)

Cheers George

a.wayne's picture

Looks like Bi Polar not enuff class A bias for MOSFETS ..!


a.wayne's picture

When was this changed from 33% of rated output to a 1/8 ..?

John Atkinson's picture
a.wayne wrote:
When was this changed from 33% of rated output to a 1/8?

The 1/3 power pre-conditioning had always been unpopular with manufacturers as it required large heatsinks, so in 2000 the FTC revised the pre-conditioning requirement to cope with the advent of multi-channel class-AB amplifiers - see my report on the FTC's "Amplifier Rule" at

I continued using the 1/3 power pre-conditioning for many years, but fairly recently adopted the revised FTC test. I now only apply the 1/3 power test when an amplifier remains cool with the 1/8 power testing.

John Atkinson
Technical Editor, Stereophile

Ortofan's picture

... a pair of power amps in order to attain a state of "bliss" when listening to music reproduced by Harbeth 40.3 XD speakers?
Harbeth's US distributor (as well as a retailer) might well want you to believe so.

However, you might want to know which amp Harbeth's owner/designer Alan Shaw uses at UK hi-fi shows to best demonstrate his company's products.
He has bought and uses Hegel H360/H390 integrated amps. The H390 presently sells for a mere $6,600.

Further note that Mr. Shaw has indicated that a peak power output of about 150W (@ 6 ohms) is likely to be sufficient for most home listeners using his speakers. A Hegel H190 is capable of about 225W continuous and about 320W peak (@ 6 ohms), and is now available for only $2,800.

If JVS observed that the -12dB indicator illuminated only briefly, and the -9dB LED never lit, then he was using, at most, about one-tenth of the maximum output power of which the JMF amps were capable - so, well under 100W. While the H190 would meet that requirement, it would struggle with the 1 ohm EPDR of the Alexia V speakers; however, the H390 would handle it with relative ease.

funambulistic's picture

I was expecting your cost analysis the first day this review dropped. Now do the Luxman!

Ortofan's picture

... that Luxman integrated amp was recommended to Alan Shaw, he deemed it to be too expensive, so instead he bought the cheaper Hegel units.
(Plus, he was under the incorrect impression that Hegel products were made in Scandinavia.)