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).
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.