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Marantz PM-KI Ruby Integrated Amplifier and SA-KI Ruby SACD Player with DAC

I’ve abbreviated the names of these two components in the title of this review so that they wouldn’t occupy half the page. Their full names are a mouthful: Marantz PM-KI Ruby Ken Ishiwata Signature Reference Integrated Amplifier and Marantz SA-KI Ruby Ken Ishiwata Signature Super Audio CD Player with DAC. “KI” are Ken Ishiwata’s initials, the redundancy, I assume, because the full moniker might not survive a parsimonious copyeditor’s blue pencil. Ishiwata has been with the Marantz Corporation since 1978 and was its principal design auteur for most of that time. The first product to sport his initials and be designated a “signature” model—to my knowledge no one else in product development at Marantz (or any other Asian audio manufacturer?) has been given similar distinction—was, I believe, the CD-63 Mk II K.I. Signature, a tweaked out budget-level CD player marketed as a limited edition that got excellent reviews, sold out fast, and quickly acquired cult status (scarce to nonexistent on the used market, they are treasured by their owners, and at least one major audio reviewer retains it as a reference). 

About ten years ago in anticipation of his third decade with the company, Ishiwata was given carte blanche to design an integrated amplifier and SACD player, the only “limitation” being a $3500–$4000 price point. Thus was born the KI Signature Pearl integrated amp and SACD/CD player, marketed in a limited edition and also the recipient of highly enthusiastic reviews. And now, to celebrate Ishiwata’s forty years (hence, ruby) with Marantz we have a new amp and SACD/CD pair again bearing the signature moniker and offered in a limited edition: two thousand units of each component in black or Marantz’s familiar champagne gold, early adopters privileged to have matching serial numbers. I am not sure what separates these units from the “reference” line of amps and SACD/CD players that have also appeared under Ishiwata’s aegis, including the similarly priced, non-signature Reference pair I reviewed six years ago. He has stated publicly that he is not the sole designer of Marantz products, rather, the head of a team that contributes considerably to the designs. But since he is well known for including long, patient, and detailed listening as an integral, indeed determinative part of product development, perhaps the signature models indicate a more personal involvement with less delegation at the various stages of any given project or simply a more subjective voicing of the sound, about which more anon. That might explain why these latest Signatures now sport Ishiwata’s actual signature laser-engraved on the top edge of the thick faceplate of each unit together with a red LED to symbolize the ruby. Ritz and glitz? No doubt, but inasmuch as Ishiwata is one of the rare Asian designers to have attained celebrity guru status—Marantz long ago gave him the formal title of “Brand Ambassador”—those who buy the KI Rubies will doubtless value the ornament.  

I should point out that in the previous paragraph I put the word “limitation” in quotation marks because, unlike many of my reviewer brethren, I do not believe that expense necessarily, or even routinely, equates to good or superior design: experience, expertise, solid engineering, good judgment, and the like do. Except for the matter of overkill in the casework and other aspects of chassis materials and construction or a commitment to intrinsically more expensive technologies (e.g., getting high power out of vacuum tubes), there is no reason why a correctly designed amplifier in the four-grand range will not perform as well as or better than one of similar wattage costing multiples of that figure. With Ishiwata, however, “better” is a loaded word inasmuch as he believes passionately in voicing his components to sound a certain way that he freely admits is not strictly neutral but is musically beautiful, though without straying too far beyond the bounds of “acceptable neutrality” (my phrase, not his). His description of the sound of the 63 Signature (in a What Hi-Fi? interview from May 2019) could to varying degrees be applied to every product he’s had a strong hand in or at least to every one I’ve heard (including the four I’ve reviewed for TAS): “I knew it wasn’t a neutral sounding player, but it was so musical, you could enjoy listening to music forever with this player.”

Ishiwata’s favorite technology of any is analog tape, and he is known to love vinyl. A practical man, however, he realized early on that the future belongs to digital—he predicted streaming, using that very word, before anyone else in high-end audio I’m aware of even heard of the term—and built his initial reputation as a high-end auteur on the basis of the magic he could work with standard 16/44 (i.e., Red Book) CD playback. But given his preferences, it’s hardly a surprise that the digital technology he embraced and continues to embrace over all others is DSD. I have long familiarity with Ishiwata SACD players inasmuch as I’ve owned the modestly priced SA-8004 SACD/CD player ever since I reviewed it eight years ago (TAS 211), a highly musical, non-fatiguing player that “sacrifices a small amount of detail and absolute resolution for a presentation of great naturalness and musicality. It’s a player I never tire of listening to.” Two years later I reviewed Marantz’s Reference Series SA-11S3 SACD/CD player (together with the PM-11S3 integrated amplifier) and I judged it quite the best reproduction of SACD I had ever had in house, representing a real improvement over the SA-8004, notably in detail, neutrality, and overall authority, while retaining the wonderful musicality for which Ishiwata’s digital components are renowned. I’ll anticipate my conclusions to the extent that I find the KI Ruby at least as good, probably better, one reason perhaps being that Ishiwata is so committed to DSD that the new player upsamples and converts all digital inputs regardless of format of origin to DSD before final conversion to analog.  

The word is that these new components have been designed from the ground up. Maybe so, but quite a bit of technology, circuitry, build, and features from the Reference Series seems to have found its way into the Rubies. Way back when Ishiwata modified the CD-63 he was paying attention to such matters as physical damping of chassis, shielding of circuits, and feet that filter or otherwise isolate from external vibration. This may account for the unusual degree of perceived cleanliness, clarity, and velvety black backgrounds in evidence (I regret the velvet cliché, but it is the metaphor that popped immediately into mind during the first listening session). I am going to forego the usual technical descriptions, as that would involve essentially summarizing the very detailed descriptions on the Marantz website. Suffice it to say, there is a great deal of careful, original, sophisticated, inventive, and even innovative thinking here, like, to name just a few items, the liberal use of use of copper and copper plating in the chasses and jacks, a proprietary transport for the SACD/CD player, a Hypex NCore switching amplifier module, a proprietary phonostage with a JFET that eliminates the need for a “coupling condenser,” and the aforementioned circuit that upsamples all PCM signals to DSD. 

Before getting to the sound, first the features and the ergonomics. The Rubies are styled as we’ve come to expect from Marantz: svelte boxes with subtly curved side cheeks and indirect blue lighting to soften the severity of the industrial look (the review samples were in black). The front panel is not festooned with buttons and switches, as most of the features are accessed (sometimes only accessible) via the remote handset, which operates both components (if you buy the pair you get two identical handsets). Like the Reference Series, the Ruby integrated gives you tone and balance controls, two high-level inputs, a phono- stage for moving-magnet or moving-coil (100 ohms fixed) pickups, and two tape-monitor loops (I have no idea why—in this day and age most people don’t seem to need even one). The amplifier can be operated without the preamplifier (but not vice-versa) and can be configured so that additional PM-KIs can be used either for bi-amping or as the heart of a multichannel setup. The connectivity of the SA-KI will accept everything you need in the way of home digital music components, and its DAC can be used with other CD players and any music server I’m aware of (see the manufacturer’s specifications at the end of this review for a list of digital media it will accept). 

The Rubies are a pleasure to use, though, like the Reference components I reviewed, not without some annoyances. Implementing the balance and tone controls requires more menu operations than I care for and is made even more annoying by the diminutive alphanumeric displays. This is evidently because Ishiwata has strong feelings about the possibility of the display adversely affecting sound quality. But since the display can be turned off entirely via the handset, where’s the harm in making it large enough to be easily read from across the room? If I were purchasing these, I would definitely go for the champagne-gold finish instead of the black for three reasons: it says classic Marantz the way blue meters cry McIntosh; if you want that embossed signature, it practically disappears on the black fascia, while it’s plainly visible on the gold; and the small lettering in medium gray against the black is almost impossible to read in anything but very bright light (I typically used a penlight or my iPhone flashlight to read the functions). 

Speaking of annoying, switching from the mm to the mc phonostage requires something on the order of at least four operations in the menu from the handset (which the manual does a very bad job of explaining). An oddity of the mm circuit here is that its input impedance is 39k ohms instead of the standard 47k ohms. When I asked Marantz of America about this, I was told the Japanese engineers “tested many different impedances but concluded 39k ohms sounds best in the Ruby circuit.” 


The Ruby tone controls, like those on the Reference Series, are also a mixed bag. As I observed of the PM-11S3, the 50Hz center point for the bass is fine, but what good is the treble’s 20kHz except maybe for taming insufficiently damped moving-coil resonances (which should be addressed via loading)? A hinge point  of 7.5kHz–10kHz is preferable. Boost or cut is limited to +/-6dB (a 2dB reduction from the Reference and stopping with brakes screeching just short of inadequate, though it will probably prevent anyone from coming to mischief with too liberal a hand on either). For units that obviously aim for a certain amount of retro convenience, the lack of a loudness compensation circuit on the PM-KI for low-level listening is unfortunate and the lack of a stereo/mono switch is deplorable.

Unlike the Reference Series components, the Rubies have single-ended circuits so XLR jacks are eschewed. The IEC jacks will accept after-market power cords but, unlike the Reference Series, there is no separate grounding pin. Neither of these omissions bothers me—I’m not an XLR fetishist—but it’s noted for those who might be. Build-quality, manufacturing, and parts look and feel superb and both components just radiate class and distinction (especially, again, in the gold finish).

The Sound
There are two components here with at least five circuits between them that have the potential to affect the sound in major ways: the phono- and linestages of the PM-KI and the DAC, SACD, and CD sections of the SA. If I were to discuss each in detail this essay would take up more space than three reviews. Fortunately, this isn’t necessary because there are no surprises here: Whether auditioned separately or together—the Rubies are so clearly designed as a pair and go together so logically, even “naturally,” that I did most of the evaluating in tandem—the sound is Ishiwata all the way, which I mean in the most complimentary way. When it comes to truth versus beauty, there can be no doubt that Ishiwata plants his feet firmly in the rich, loamy ground of beauty. In the same What Hi-Fi? interview cited earlier he said that his favorite audio components (not designed by himself) are “Audio Research’s SP-10 preamplifier and Mark Levinson 20.5 monoblocs driving Apogee’s Diva speaker. Crazy, eh?” Crazy like a fox, maybe, because the Rubies separately or together do suggest a marriage of some of what tubes are considered to do best and some of what solid-state is considered to do best. 

Once asked what sonic qualities his perfect component would have, Ishiwata replied, “It would have a rich and warm midband for voices and an amazing three-dimensional soundstage.” I’d say he’s realized that goal. There is some of the warmth, richness, and dimensionality traditionally associated with tubes together with the precision, definition, transient attack, bottom-end extension, and impact for which solid-state is prized. If not echt neutral, it’s surely a sound that anyone who loves music would enjoy: natural, smooth, refined, and, well, that word again, beautiful. This beauty extends downward throughout the whole bottom end, which is solid, weighty, and grounded yet also capable of quite excellent definition, clarity, and real muscle when needed. By contrast the top end is easy on the ears: “crisp” and “extended” might not be the first words that spring to mind upon initial listen, but neither would “soft,” “muted,” “dark,” or “sloping.” On the contrary, there’s high resolution and detail on offer here, yet without its being highlighted, etched, or edgy, and the ambience and atmosphere of venues are reproduced very capably.  Despite its nice sense of body, it’s also rhythmically agile so that those who place high priorities on timing and the speed with which their toes get to tapping will find next to nothing to complain about, while the vitality with which these components reproduce music from all sources guarantees high engagement and involvement. 

Before going on to records and recordings, I must point out that none of the tonal characteristics I’ve described in the preceding two paragraphs are in any way gross or crude; nor do they manifest themselves as colorations or even tonal anomalies thusly defined. Ishiwata is plainly a man of refined sensibility, impeccable taste, and excellent judgment, someone who knows and loves how live music should and does sound and who would never dream of hyping, selling, or otherwise aggressively forcing his tastes upon anyone. His voicings manifest themselves principally as a warmth applied with a very light and discerning hand and an overall smoothness that always falls pleasingly upon the ear. With the Rubies you can banish all worries about component-induced fatigue.    

PM-KI Ruby: This amplifier’s hundred watts/channel are so conservatively rated that according to some measurements I’ve read it typically generates over half again that much into 8 ohms and way over the rated 200W into 4 ohms. This means that despite a subtly romantic overall character, it can do punch, slam, and wide dynamics excellently unless the speakers are monstrously inefficient and/or the room really large. I had no problems in my 2600 cubic foot listening room driving Harbeth Monitor 40.2s (an easy 6-ohm load, though its 86dB efficiency is a tick on the low side of medium) to much louder levels than I could comfortably stand. To gauge what it could do with the big stuff I started with Telarc’s extraordinary DSD recording of Mahler’s Sixth Symphony, conducted by Benjamin Zander, on an SACD. Imaging and soundstaging being high priorities with Ishiwata, I can report that the PM-KI cast a wide panorama of an augmented, late nineteenth century symphony orchestra with impressive depth and specificity of placement of instruments and instrumental groups within the soundfield. The brass and tympani emerge clearly from the rear, the winds are nicely arrayed across the center, and when the infamous hammer blows land, all three of them, it’s with startling weight and impact. String tone is lovely, pure, and true, without any sort of harshness or steeliness, while the trumpets top the texture with authentic brilliance yet no glare. 

I next went to Kei Koito’s sensational Bach organ recital (Claves CD): the opening Toccata of the Toccata and Fugue in D Minor has deep organ pedal-points that will test any amplifier’s stamina, its ability to sustain current over several measures while the upper registers pile on the textures. Again, the clarity, tonal fullness, separation of lines and pitches were all first rate, and the ambience of the venue was convincingly reproduced, notably the die-aways at the ends of phrases or movements. Anyone who continues to insist that Red Book digital doesn’t allow a proper acoustic fadeout is either an analog zealot or needs to upgrade his equipment.

That the PM and SAs can do delicacy, nuance, and detail superbly was easily demonstrated when I put on the vinyl, the SACD, and the CD of “Sweet Baby James” from Jacintha’s tribute to James Taylor (Groove Note), the voice so immediately present and three-dimensional that I almost caught my breath. A bit later I played a DSD128 download of the same thing and I did catch my breath. Likewise, Lyn Stanley’s London Calling brought similar pleasures and revelations. The “Summertime” duet between her and the pianist Mike Garson that I singled out in my TAS review was spooky in its you-are-there presence, and exquisite in how well were conveyed the expressive nuances of singer and pianist. 


Male voices are handled equally well, whether Sinatra at his saddest on Only the Lonely, Matthias Goerne at his darkest in Schubert ‘s Winterreise, or Paul Hillier at his most ironic on Bitter Ballads (all three on CD from Reprise, Decca, and Harmonia Mundi, respectively). A favorite I’ve owned since I first got into quality reproduction back in the Sixties is the collection of sea songs and shanties by the male chorus of the Robert Shaw Chorale (RCA vinyl and 16/24 via Tidal through NAD’s M50.2 into the SA-KI’s DAC). This splendid program remains as entertaining as the day I bought it, whether for the eye-popping virtuosity of “The Drummer and the Cooke” or the melancholy strains of “Shenandoah” (in one of its best arrangements by the near-legendary Alice Parker). Shaw pioneered a method of getting choristers to pronounce words properly, and you can track virtually every word, even at the all but frenetic tempo of “What Shall We Do with a Drunken Sailor?” I’ve heard some setups come a cropper on this number (especially on the vinyl), but the Rubies sailed through it without blur or smear. This is by any standard a really superior recording of a small chorus, ideally mediating atmosphere and focus, with imaging that lets you enjoy the antiphonal effects in, say, the rounds as the tunes are passed from one section of the group to another.

PM-KI phonostage: Ishiwata is particularly and justifiably proud of this phonostage, which eschews chip-based op-amps in favor of discrete circuits. Fed by an Ortofon Cadenza Bronze in a Basis Vector IV/2200 combination, it gives you wide dynamic range, very low noise (I really had to crank it to hear any, even with an mc as low output as the Ortofon), and plenty of meaningful detail. One of the first things I put on was the DG recording of Bernstein conducting the entire string section of the Vienna Philharmonic in Beethoven’s Op. 131 quartet, a desert-island recording chez Seydor, one I use every time I review equipment. I was astonished. The string tone was drop-dead gorgeous, the back to front layering something to behold, with great separation of textures without sacrificing the gestalt. The plucked strings made me sit up in my seat. When it was over my first note read, “What life and vitality there is here!” 

A sometime rap against Ishiwata’s designs is that smoothness takes precedence over drive: put paid to that by spinning Keith Jarrett’s Koln Concert, which I did one afternoon and found myself riveted through all four sides. As everyone must know, this was for Jarrett an occasion fraught with frustration: the piano, although a Bösendorfer, was not in good condition and frantic last-minute efforts by a tuner didn’t come close to making a silk’s purse out of it. Jarrett reluctantly consented to do the concert and in the event it turned out to be a great occasion, perhaps his signature achievement in recording. No, the piano doesn’t sound particularly good, but in the face of musicmaking of such commitment, fire, and inspiration, it just goes to show that it’s artist, not the instrument, that really matters. Jarrett’s various vocalizings are easily discerned through even the loudest, thickest passages and the presence of the audience is palpable.

A new album by the jazz guitarist Anthony Wilson (one of Diane Krall’s favorite collaborators) called Songs and Photographs, in which Wilson sings and plays songs of his own devising, is a recording of state-of-art purity and truth to timbre: It isn’t audiophile spectacular, rather just unobtrusively right (Joe Harley the producer, Michael C. Ross the engineer). The transparency is such you’d be forgiven for thinking no electronics were used in the recording. (The drum kit here will certainly test your system’s mettle if you wish to lay a heavy hand on the volume.)

SA Ruby SACD and CD: I might as well lay my cards on the table and admit that all other things being equal I think well-executed DSD is the best recording medium on the planet, indeed the best ever devised. It lacks the colorations and the speed—and thus the pitch—instabilities of even some of the very best vinyl reproduction (likewise analog tape, though tape’s instabilities of pitch are far less egregious than vinyl’s); it is source accurate with the widest dynamic envelope, the lowest noise and distortion, and the highest neutrality. When I reviewed the Reference Series SA-11S3 I judged it the best SACD player I had ever had in house. That was six years ago. I’d have to lie to say that my sonic recall is so infallible that I can pronounce the Ruby superior. What I can say for certain is that the Ruby gave me the best SACD reproduction I’ve had in house or with which I’ve had long experience since the SA-11S3, and it might be even better. As I’ve already described its performance on several SACD recordings, let me add only that all the recordings I typically use for reference and reviewing purposes were reproduced superbly. A powerful new recording by Susanna Maliki, a strong up and coming conductor, of Bartók’s Miraculous Mandarin Suite (BIS) allowed the SA to show off its imaging capabilities and its dynamic range. Freddy Kempf’s recording (BIS) of the “Moonlight” and “Pathetique” sonatas brings the piano into the room in a powerfully persuasive way. The same is true of Angela Hewitt’s very different sounding instrument, a colorful Faziolli, in the Bach Toccatas (Hyperion). And one of the most exciting recordings I listened to during these evaluations was Jordi Savall’s La Folia (Alia Vox): a riot of colorful olde instruments thrillingly performed in a magically atmospheric setting. 

While Ishiwata’s commitment to DSD/SACD is absolute, he is the first to admit that Red Book properly implemented can be nearly as good, which this new player demonstrates to a fare thee well. As with the SACD playback, so with the CD: this is the finest reproduction I’ve heard from any single-unit player I’ve ever owned or had long experience with. Does this owe to the converting of all PCM to DSD? I have no idea (see sidebar for more on this), but the clearly observable differences I routinely hear between Red Book and SACD of the same source were with this player narrower than I’ve previously experienced.  

As with the Reference SA-11S3, this new Ruby has a pair of filters for Red Book reproduction, described in manual this way: 1: “Very precise soundstage and smooth tonal balance.” 2: “Neutral tonal balance—slightly brighter than Filter 1.” You couldn’t prove the superior imaging of 1 over 2 by anything I played, but 1 does sound a smidgeon smoother and 2 a tad brighter. But they are close enough that I’m pretty sure I couldn’t identify which was which on unfamiliar material (this was not the case with the filters on the Reference player). One of my notes suggests that percussive instruments, like a piano, sound a bit more percussive on 2, a bit less so on 1. (Neither filter is a default, meaning that whichever is engaged upon turn-off will be engaged upon turn-on.)

KI Ruby DAC: The built-in DAC here is so good I doubt that most prospective buyers will feel the need or the desire to move beyond the player itself once they add a music server. I spent a great deal of time using this DAC for streaming, both from my computer and, better still, an NAD M50.2 music server, with results that were essentially limited only by the quality of the source material. Indeed, at least half or more of my evaluations consisted in streaming Tidal or Qobuz routed through KI’s on-board DAC. The quality of reproduction was always at least as good as the highest CD quality and frequently better if the file was hi-res or MQA. I also listened with great pleasure to hi-res downloads. Among the very best sound I got regardless of format were downloads of DSD files, typically superior to the best vinyl. The DSD file of Jacintha’s Johnny Mercer album (Groove Note) was unsurpassed in my experience for sounding as if I had a direct connection back to the source.

Six years ago I began my review of Ishiwata’s Reference Series by observing that it was impossible not to be impressed by them. The same is true of these new Rubies, yet I would also add that it is equally impossible not to be impressed by the value they offer. Think about it: You have a 100Wpc amplifier (typically 150W or more); a preamplifier with a phonostage and a number of useful features; and an SACD/CD player with a built-in DAC that together will handle virtually every digital medium for the playback of music in the home—all of superlative performance, plus quality of build, parts, manufacturing, and workmanship that cannot be faulted. While at $3999 each they cannot be considered inexpensive, in the increasingly lunatic world of high-end audio pricing they certainly represent amazing value when you figure their sonic performance invites comparison on an absolute scale and leaves virtually nothing to be desired. My personal reference electronics are so good—McIntosh C52 preamplifier with DAC, Benchmark DAC1, Benchmark AHB2 amplifier, Phenomena II phonostage—that I’m always happy to return to them when reviewing duties are over. These new Marantzes haven’t changed this, but they are so good that should I ever decide to simplify my system without serious compromise, they would rank very high on any shortlist (my annoyance with certain aspects of their ergonomics notwithstanding).

Meanwhile, I was nearly finished with this review when I read the announcement that Ken Ishiwata is leaving Marantz because, I was told by the importer, that at nearly eighty Ishiwata has decided it’s time to retire. If this is true, then the KI Ruby Signatures become in effect his valedictory designs. Should this turn out to be the case, they are surely as fitting a valediction as he could desire, realizing as they do his highest and most cherished ideals in the reproduction of music in the home. {Editor’s note: We were saddened to learn that Ken Ishiwata passed away last November.}

Specs & Pricing

Marantz PM-KI Ruby integrated amplifier 
Power output: 100Wpc, 8 ohms, 200Wpc, 4 ohms at 0.01% THD, 5Hz–50kHz
Inputs: Three unbalanced, two tape loops, one phono, power-amp in, all on RCA jacks
Dimensions: 17.32″ x 5″ x 17.83″ 
Weight: 34.61 lbs.
Price: $3999

Marantz SA Ruby Super Audio CD player with DAC
Frequency response: SACD 2Hz–50kHz at 0.0008% THD, CD 2Hz–20kHz at 0.0015% THD 
Inputs: Optical, coaxial, USB-A (front), USB-B (rear)
Outputs: Single-ended, balanced, optical, coaxial
Dimensions: 17.32″ x 5″ x 16.5″ 
Weight: 37.7 lbs.
Price: $3999

100 Corporate Drive
Mahwah, N.J. 07430-2041


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