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JMF Audio HQS 7001 Monoblock Amplifier and PRS 1.5 Linestage

JMF Audio HQS 7001

Over the years I’ve heard and reviewed many fine solid-state amplifiers from the U.S., Canada, Great Britain, Switzerland, Germany, The Netherlands, Scandinavia, various Eastern European countries, and Japan. What I haven’t yet heard or reviewed is a solid-state amplifier from France.

That is about to change.

Though I’m a bit of a Francophile when it comes to food, wine, art, literature, and music, I haven’t really dipped more than a toe or two in French hi-fi—and that dip, with various Jadis tube amplifiers in the 1990s, was a cautious one. (Back in the day, Jadis’ longtime U.S. distributor, the late Victor Goldstein, who was sadly taken from us at the start of the COVID epidemic, used to turn his head away and shield his eyes every time he switched on a big Jadis monoblock—for fear of fireworks.) Just lately, however, I’ve gotten several pieces of pricey solid-state Gallic gear—two of which, JMF Audio’s HQS 7001 monoblock amplifier and PRS 1.5 linestage, I’ll be reviewing here. (A separate article on the third, Analog Audio Design’s TP-1000 15ips reel-to-reel tape deck, is forthcoming.)

If you’ve never heard of JMF Audio, join the crowd. Until its importer, Audio Skies’ Michael Vamos, and its brand ambassador, Fidelis Audio’s Walter Swanbon, showed up at my door bearing gifts, I hadn’t heard of JMF, either. But then you and I don’t run a recording studio, which is where JMF’s founder, the late Jean-Marie Fusilier, made his reputation. Though his original company (founded in 1974) specialized in high-frequency and infrared remote-control systems for industrial, defense, and nuclear-plant applications, Jean-Marie was also a passionate music lover and audiophile (does this begin to sound familiar?), and in 1985 he launched a side business to “develop linear audio solid-state power amplifiers, using high-voltage rails for greater headroom, high-current-enabled outputs for the best control of the speakers, selected and matched transistors for linearity, high-purity materials to carry the signal, short-signal-path circuit design, direct coupling in the output stage, high internal energy reserve for best transient response, made-to-measure passive components from specialists in aerospace and defense, and techniques and parts normally intended for telecom and radar systems.” His novel amplifiers soon caught the eyes and ears of several celebrated recording engineers in Europe and the U.S., who bought them for their studios. (Artists who have recorded in venues equipped with JMF amps make for a veritable Who’s Who of late-twentieth-century and early-twenty-first-century musicians, ranging from Sting, INXS, Robert Palmer, and Aerosmith, to Willie Nelson, Shania Twain, Celine Dion, and Mariah Carey, to the London Symphony Orchestra and the Moscow Symphony Orchestra and scores of others.)

Though his amps were a commercial success in the pro-audio world, Fusilier was too busy with his industrial and defense remote-control business to broaden his market in the consumer sector. Happily, his sons Laurent and Arnaud, university-trained electrical and mechanical engineers (and music lovers), joined JMF Audio in the early 2000s. Under their guidance, JMF developed and introduced a jackpot of new high-end-audio products, including what might have been the first 768kHz DAC (2003), a psychoacoustically based DSP crossover (2005), the HPM line of loudspeakers (2007–2009), and the CSV pure analog precision volume control, along with many other advanced components, including the amp and preamp under review.

To look at, the JMF HQS 7001 monoblocks are unprepossessing. Though not as strictly no-frills as Fusilier père’s pro-audio originals, they remain (a bit deceptively) utilitarian in appearance—squat, rectangular, completely sealed boxes, made from 10–16mm-thick anodized and brushed aluminum parts. What makes these chassis deceptive is that they actually house a second chassis, within which all the 24k-gold-plated circuit boards, resistors, capacitors, transistors, and transformers are painstakingly segregated and mounted. Both chassis sit on proprietary decoupling feet.

The front-panel controls are equally spare and functional: towards the right center, a vertically aligned series of three small LEDs, which, when lit, indicate overload, DC offset, and high temperature; towards the bottom center, an on/off pushbutton; and on the right center, another vertically aligned series of seven numbered LEDs, which, when metering is activated, light up to indicate output levels (from -15dB to +3dB). There is a toggle switch beneath the metering LEDs to turn the meter on and off (an LED above the switch indicates its status).

The back panel of the amp is just as spare and functional as the front: on the far left at the top is an XLR input, beneath which are two sets of positive/negative speaker connectors (one set gold-plated WBTs and the other proprietary 6mm LSS), below which, at the bottom left, are a 4mm grounding socket and a captive power cord. (JMF supplies its own pc’s for the HQS 7001; there is no IEC option for aftermarket cords.) To the right of these inputs and outputs are the rear-mounted cooling fins.

JMF Audio PRS 1.5

The dual-mono, fully balanced PRS 1.5 linestage preamplifier virtually duplicates most of the design touches found in the HQS monoblocks. It, too, is housed in a double chassis made from thick brushed and anodized aluminum parts. It, too, has a spare and functional front panel, with a large, circular, dual-bearing volume control at its center that is absolutely silken in operation, a rectangular LED panel to its right to indicate volume level, source, and other parameters, and, to the panel’s right, two pushbuttons that switch sources, mute the preamp, put it in standby, or select a “direct” connection for use with a tape recorder or a headphone amplifier. The back panel of the preamp is the only “busy” spot on either JMF component. It is loaded with inputs (three pairs balanced, three pairs unbalanced) and outputs (two balanced, one unbalanced), a 4mm grounding socket, an on/off toggle, and oddly (given the dedicated power cords on the amps), an IEC socket for the cord of your choice.

Internally, there have been many changes to the JMF amps and preamps over the years, but the fundamental design approach has stayed the same. For the amps, the goals remain “high reserves of energy for instant delivery at the output on fortissimos; high voltage for superior headroom and higher efficiency; and high current output for best possible control of loudspeakers, allowing the amplification structure to limit the use of compensations, such as excessive feedback loops.” For the preamp, the goals are “the absence of insertion loss and faithfulness to the music,” achieved in part via the PRS’ patented CSV volume control, which, rather like Soulution’s ingenious vc, uses digitally driven and galvanically isolated stepped attenuators to set levels with high precision, lower noise, zero-out phase shift, and increase output headroom.

JMF Audio HQS 7001 rear

Most of the changes made in JMF’s latest electronics involve the build and selection of component parts—the fruits of long research and experimentation. “The JMF Audio HQS power amplifiers and PRS preamplifier utilize selected and uncommon devices for audio applications: high-frequency precision transistors in matched differential pairs, bespoke passive parts, proprietary dual-sided circuits boards coated in 24k gold to which caps, resistors, and transistors—over 700 of them on certain boards—are hand-mounted and hand-soldered using bespoke solder.”

The results, JMF claims, are amps and preamps that lower noise to a minimum, preserve signals with no insertion losses, and better control the counter-electromotive force of loudspeaker drivers and crossovers by means of the unstinting delivery of current. “Large signals never mask small signals. Notes last longer. And dynamics remain ‘linear’ down to the lowest levels, allowing the reproduction of the smallest details, the subtleties of ambience, and the wide and coherent natural soundstage caught at the recording.”

As was the case with Magico’s S3 2023 loudspeaker, JMF’s big sonic claims for its electronics turned out to be verifiable. Indeed, and rather ironically given that JMF pointedly limits the use of negative feedback and the Swiss company Soulution embraces it (in a highly ingenious and sophisticated form), upon listening to the HQS 7001 monoblocks and PRS 1.5 preamplifier, my first thought was that they sounded uncannily like my reference Soulution 711 amplifier and 727 pre in tonal balance, transient response, harmonic/dynamic duration, and sheer density of musical information.

Sonic density is something I’ve touched on in other places (it is part and parcel of what I call completeness), but with these French electronics (and Soulution’s Swiss offerings), it is a bedrock virtue. To apply an analogy I’ve used before, if you think about how a half-tone print of a photograph looks—in which everything is reduced to a separate dot of pure white, grey, or pure black (rather, dare I say it, like the data streams in digital audio)—and compare it to the appearance of a continuous-tone photograph, in which the same image is reproduced in a broad, smooth, unbroken spectrum of blacks, greys, and whites, you’ll get what I mean by density. Details which stand out coarsely in the half-tone are subsumed into wholes in the continuous-tone print. They’re still there, of course, but they are blended and unified, as they are in life, into a sonic image that is completely and realistically “filled in.”

Why JMF’s electronics should so fully share this signal virtue with Soulution gear, which (as noted) uses a very different design approach, is an interesting question to which I don’t have a really good answer. Given the emphasis JMF puts on its use of 24kt gold reminded me that the gold-wire interconnect and speaker cable from Siltech that I used to fiddle with, lo, these many years ago, also had a similar and beguiling density of texture and timbre, only the gold wire seemed to soften dynamics and mask detail, and the JMF gear does not.

I doubt that the answer to this conundrum is simply the superior application of gold-plated circuit boards. More probably, it is the greater control and noiseless purity of the high current (112 amps in the 300W HQS 7001 monoblocks) generated by the HQSes’ temperature-regulated, individually powered, multiple-matched-resistor, capacitor-free, zero-inductance output stages, which really do seem to handle speaker loads (such as that of the 4-ohm/85dB-sensitive Magico 2023s) with iron grip. (The 7001’s high damping factor of better than 1200 doesn’t hurt, either.) The PRS preamp’s extremely low noise and sheer density of musical information obviously complement the amp’s control and purity.

Given a high-resolution loudspeaker like the Magico S3 2023, you can hear the results of the JMF components’ combined virtues on something as seemingly straightforward as “Ndugu” Chancler’s initial drumbeats from “Billie Jean” on Thriller. The HQS/PRS’ tone color is so intensely rich, its reproduction of instrumental body so sensationally three-dimensional, its resolution of detail so fine that you can not only clearly visualize the foot pedal, beater, and kickdrum head Chancler is using; you can also hear the mechanisms—the slight metallic squeak of the pedal spring and linkage assembly—that are making the contraption work. The same holds true for performance and mix details, like Steve Lukather’s great rhythm guitar intro to “Beat It,” in which his intermittent percussive chucking becomes as clear as day, or the incredible font-to-back and side-to-side soundstage spread of Michael Jackson’s yips, yaps, and backup vocals, which pop up (all over the stage) with a color, clarity, and three-dimensionality that are astounding.

However, saying that the HQS/PRS is a monster of resolution is a bit misleading, as those words imply a thinned-down, analytic presentation. The fact is that through JMF gear you don’t hear the things I just mentioned from the MJ album as if they are separate, spotlit details. You hear them as indivisible parts of wholes. Indeed, you need to willfully pay attention to such minutiae to isolate them as I have, so fully blended are they with instrument and instrumentalist in the JMF soundfield. This is one reason why I kinda disagree with another rave review of top-line JMF electronics by a writer I know well and admire, which compared the HQS amps and PRS preamp (quite favorably) to proverbial straight wires with gain. This famous analogy is meant to convey the notion that nothing is added or subtracted between the original signal and its reproduction. While the minimization of “insertion loss” is, as noted, one of JMF’s goals, beyond their outstanding holism its amps and preamp, nonetheless, have a sound of their own. That it happens to be a sound I’m crazy about (and find very lifelike) doesn’t make it any less of a sonic signature.

To wit, like the Soulution and MBL components that are my references, the JMFs are a bit “bottom-up” in character, which is to say that they are weighted slightly (albeit congenially) to the bottom octaves and the midrange, while their top end is sweet, soft, and liquid—anything but aggressive or bright. In other words, the JMFs have an inherently rich, full, darkish tonal balance. (All the solid-state amps I’ve preferred do.)

While this might seem to make them less than fully source-neutral and transparent, that is not the case. The JMFs faithfully reflect miking, mixing, and performance style. For instance, on the great Kevin Gray/Cohearent Audio mono reissue of Chet Baker Sings [Blue Note Tone Poet], you can clearly discern how close Baker is to the mic (which, according to the liner notes, was a tube-powered Western Electric 640AA condenser, even though the mic in the cover photograph is clearly an RCA 44-BX ribbon—and sounds like one). The fact that Baker is virtually swallowing the microphone makes the image of his voice considerably larger than, say, MJ’s precisely imaged background vocals potted in on Thriller.

Of course, you can hear many of these differences in image size, mic type, and performer/mic location through virtually any high-quality amplifier. What you won’t necessarily hear is the way this superb reissue increases the color and body of Chet’s whispery high-tenor throughout its narrow, near-monotonal two-octave range (A2–A4) or the clarity of the minor-key excursions Chet adds to his delivery of the lyrics (notably at the ends of songs), keeping things appropriately intimate and just a tad characteristically inconclusive. (It’s as if you were expecting a final note or cadence that Baker deliberately doesn’t deliver, leaving the emotional tenor of the lyrics a little jazzily mixed.) Despite the very close miking, you don’t hear a trace of the sibilance or whistle that you hear on Louis Armstrong’s equally closely miked vocals on Ella and Louis.

Given the analogies I’ve drawn to Soulution gear, you’re probably wondering if the two are sonically identical. The answer is more yes than no, but there are no-parts. In addition to their sensational soundstaging, the JMFs project spotlit vocals and instrumentals a bit closer to the plane of the loudspeakers than the Soulutions do. This has no effect on soundstage depth; in fact, it rather increases the illusion of depth with ensembles in which other vocalists or instrumentalists are situated further back on the boards. The JMFs’ soundstage may also be a wee bit wider than that of the Soulutions, although this depends on the recording. In addition, the amps’ upper midrange is a touch more prominent (q.v., their slight imaging forwardness). Functionally, unlike Soulution, JMF does not offer a (superb) optional built-in phonostage for its preamp. The PRS 1.5 is strictly a linestage. And at 300W into 8 ohms, the JMF HQS 7001s are nominally a bit more powerful than the Soulution 711, which means you can play your music even more unbearably loudly, for what that’s worth.

In noise, resolution, tonal color, dimensionality, dynamic range, and that magical sense of presence that makes recorded instruments and musicians sound as if they’re in the room with you (or you in the room with them), the JMFs and Soulutions are so closely matched that I can’t hear much difference between them. Both are also exceedingly lifelike when it comes to the durations of notes. Neither overemphasizes the starting-transient phase of the dynamic/harmonic envelope, as solid-state amps of yore always did —and many of today’s highest-enders still do. The amps and preamps from both marques give equal time to the development of steady-state tone and decay, which is why their presentations have such lifelike fullness of color, three-dimensional body, and dynamic expressiveness from the softest passages to the loudest ones.

To prove this last point, all you need do is subject the JMFs (or Soulutions) to a musical workout such as the Smetana Quartet’s performance of 20th-century Czech composer Jindrich Feld’s String Quartet No. 4—a neo-Bartókian piece recently gifted to me on LP by my music-loving friend Mark Lehman. In Feld’s Fourth Quartet, dodecaphonic themes are driven along by constant (often abrupt and violent) changes in timbre, intensity, duration, pitch, and articulation. (Feld makes use of just about every bowing technique in a string player’s repertoire, from mournfully sustained notes on single strings, to leisurely legatos, to percussive martelés, to fleet sautillés, to herky-jerky glissandos that descend the scales like a drunk stumbling down a staircase, to entire passages played pizzicato.) The piece is a musical tour de force, which the JMFs reproduce with as much you-are-there realism as good miking in a large, warmish hall will allow. Through the JMFs, the two violins, the viola, and the cello never sound as if they are all string (i.e., all starting transient); even on the pizzicatos you get a healthy taste of soundboard and wooden body and the rich reverberance of decay.

Bottom line? JMF’s amps and preamp may be new to me (and to you), but if I have a say in it, they won’t stay that way for long. (Our sister magazine, hi-fi+, has already awarded them Product of the Year awards.) I plan to listen to more of the French company’s offerings as soon as I can get my hands on them—and intend to add the HQS 7001s and PRS 1.5 to my collection of reference electronics. These are world-class offerings that do just about everything musical as well as such things can be done by solid-state components, even in comparison with the world’s finest competition. If you’re in the market for topnotch monoblocks and a superlative linestage (and have the requisite l’argent), well…vive la France!

Specs & Pricing

HQS 7001 mono amplifier
Input connection: XLR, gold contacts
Input impedance: 20k ohms
Interference rejection: 100dB typ.
Gain: 34.6dB
Output connection: JMF Audio LSS dia. 6mm (120A continuous rated) and gold-plated WBT for forks or wires
Output power RMS: 300W/8 ohms, 500W/4 ohms, 850W/2 ohms
Output current capability: 112A
Load impedance: >1.5 ohms recommended (tested down to 1 ohm at full output power at the manufacturer)
Monitoring: Level metering (-15dB to +3dB, deactivatable), input offset, overload, high temperature
Bandwidth: Better than 0.1dB 3Hz–20kHz for 250W/4 ohms, small signals better than 1dB at 100kHz
THD+N: Better than 0.01% for 250W/4 ohms at 1kHz (0.001% typ. un-loaded) BW. 20Hz–20kHz
Signal-to-noise ratio: 110dB typ. un-weighted 20Hz-20kHz
Damping factor: Better than 1200 at 8 ohms, wide band
Audio signal coupling: Direct coupling
Dimensions: 19″ x 5.9″ x 21.5″
Net weight: 75 lbs. apiece
Price: $77,900/pr.

PRS 1.5 dual-mono linestage preamplifier
Balanced inputs: 3
Unbalanced inputs: 3
Balanced outputs: 2 allowing biamplification
Unbalanced outputs: 1 modular, fixed or variable
Volume display: 30 to 99
Input impedance: >10k ohms (XLR and RCA inputs)
Maximum input level at low volume: 9V (+20dBu, XLR bal)/4V (+14dBu, RCA)
Maximum input level at max volume: 10V (+22dBu) into 10k ohms load
THD+N: 0.0002% typ. (+22dBu 1kHz in/20Hz–22kHz)
Interferences rejection (balanced input): 100dB typ.
Maximum output level: 3V (+11dBu, XLR bal)/1.4V (+5dBu, RCA), version F
Global signal bandwidth: 1Hz–150kHz (intentionally limited for RF immunity), 20Hz–20kHz (+0.0/–0.0dB)
Signal-tonoise ratio: 120dBA typ. (+22dBu), version F
Channel separation: >100dB (10V output 1kHz, gain min.)
Output impedance: 50 ohms
Maximum gain output/input: 12dB (XLR in), +18dB (RCA)
Volume control range: 70 steps of 1dB
Volume control step precision: Better than 0.05dB above volume 40 < 0.1dB above volume [40]
Dimensions 19″ x 4.2″ x 12.6″
Net weight: 31 lbs.
Price: $39,000

AUDIO SKIES (U.S.A., Canada, and U.K. Importer)
Los Angeles, CA
(310) 975-7099
audioskies.com

JV’s Reference System

Loudspeakers: MBL 101 X-Treme MKII, Magico S3 2023, Magnepan 1.7 and 30.7
Subwoofers: JL Audio Gotham (pair), Magico S Sub (pair)
Linestage preamps: Soulution 727, MBL 6010 D, Siltech SAGA System C1
Phonostage preamps: Soulution 757, DS Audio Grand Master EQ
Power amplifiers: Soulution 711, MBL 9008 A, Siltech SAGA System V1/P1, Odyssey Audio Stratos
Analog source: Clearaudio Master Innovation, Acoustic Signature Invictus Neo/T-9000 Neo, TW Acustic Black Knight/TW Raven 10.5
Tape deck: United Home Audio Ultima Apollo, Metaxas & Sins Tourbillon, Analog Audio Design TP-1000
Phono cartridges: DS Audio Grand Master EX, DS Audio Grand Master, DS Audio DS-W3, Clearaudio Goldfinger Statement v2.1, Air Tight Opus 1, Ortofon MC Anna, Ortofon MC A90
Digital source: MSB Reference DAC, Soulution 760, Berkeley Alpha DAC 2, Kallista DreamPlay XC
Cable and interconnect: Synergistic Research Galileo SRX (2023), Crystal Cable Art Series da Vinci, Crystal Cable Ultimate Dream
Power cords: Crystal Cable Art Series da Vinci, Crystal Cable Ultimate Dream, Synergistic Research Galileo SRX 2023
Power conditioner: AudioQuest Niagara 5000 (two), Synergistic Research Galileo SX
Support systems: Critical Mass Systems MAXXUM and QXK equipment racks and amp stands
Room Treatments: Synergistic Research Vibratron SX, SteinMusic H2 Harmonizer system, Synergistic Research UEF Acoustic Panels/Atmosphere XL4/UEF Acoustic Dot system, Shakti Hallographs (6), Zanden Acoustic panels, A/V Room Services Metu acoustic panels and traps, ASC Tube Traps
Accessories: DS Audio ES-001, DS Audio ION-001, SteinMusic Pi Carbon Signature record mat, Symposium Isis and Ultra equipment platforms, Symposium Rollerblocks and Fat Padz, Clearaudio Double Matrix Professional Sonic record cleaner 

Tags: AMPLIFIER JMF LINESTAGE MONOBLOCK POWER

Jonathan Valin

By Jonathan Valin

I’ve been a creative writer for most of life. Throughout the 80s and 90s, I wrote eleven novels and many stories—some of which were nominated for (and won) prizes, one of which was made into a not-very-good movie by Paramount, and all of which are still available hardbound and via download on Amazon. At the same time I taught creative writing at a couple of universities and worked brief stints in Hollywood. It looked as if teaching and writing more novels, stories, reviews, and scripts was going to be my life. Then HP called me up out of the blue, and everything changed. I’ve told this story several times, but it’s worth repeating because the second half of my life hinged on it. I’d been an audiophile since I was in my mid-teens, and did all the things a young audiophile did back then, buying what I could afford (mainly on the used market), hanging with audiophile friends almost exclusively, and poring over J. Gordon Holt’s Stereophile and Harry Pearson’s Absolute Sound. Come the early 90s, I took a year and a half off from writing my next novel and, music lover that I was, researched and wrote a book (now out of print) about my favorite classical records on the RCA label. Somehow Harry found out about that book (The RCA Bible), got my phone number (which was unlisted, so to this day I don’t know how he unearthed it), and called. Since I’d been reading him since I was a kid, I was shocked. “I feel like I’m talking to God,” I told him. “No,” said he, in that deep rumbling voice of his, “God is talking to you.” I laughed, of course. But in a way it worked out to be true, since from almost that moment forward I’ve devoted my life to writing about audio and music—first for Harry at TAS, then for Fi (the magazine I founded alongside Wayne Garcia), and in the new millennium at TAS again, when HP hired me back after Fi folded. It’s been an odd and, for the most part, serendipitous career, in which things have simply come my way, like Harry’s phone call, without me planning for them. For better and worse I’ve just gone with them on instinct and my talent to spin words, which is as close to being musical as I come.

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