Plinius Koru Phonostage

REVIEW
by Paul Seydor
Sep 05, 2013

Nothing like beginning with a confession: It’s getting to be that one of the hardest categories of components to review is solid-state electronics in the moderately expensive category. To begin with, most of them are so good they must give anyone but hedge fund managers, oil barons, and top Fortune 500 CEOs pause before spending a whole lot more. And not just good, but good in a way that brings them closer and closer together in sound. I’m not resurrecting the canard that electronics that measure similarly sound the same, only that I find it often takes a great deal of very critical listening to ferret out differences that, once ferreted out, sometimes hardly seem worth the effort. These components are for the most part neutral in tonal balance, extremely low in noise and distortion, highly transparent, and offer bagsful of performance at prices that, while hardly inexpensive, are not outrageous, especially by comparison to products in the stratosphere.

These musings are prompted by a superb new phonostage, retailing for $3900, from a manufacturer whose products are relatively new to my personal experience, though the company has been around for a long time—the New Zealand firm Plinius. Before I listened to a note of music, the Koru pushed all my buttons by offering enough options for loading and gain to handle all moving magnets and the majority of moving coils likely to be used with it (also unusual is adjustable capacitance). styled with curved front panels to match the current Plinius look and available in black or silver, the Koru’s fascia is stark, boasting nothing more than a blue LED and the engraved “Plinius” moniker. The business end is the rear panel, where DIP-switches select loading and levels and there is a balanced output in addition to the single-ended RCAs. Plinius claims the Koru’s power supply “boasts a virtual battery approach with over 100,000mF of capacitance and very sophisticated two-stage regulation.”

I’m not sure what a “virtual battery approach” means, except perhaps impressive AC isolation, but I’ll tell you this: The Koru is one super-quiet phonostage. Operation couldn’t be simpler or more straightforward. Determine the loading and level values of your pickup—if you care about this (and you should)—set the switches, hook everything up, and drop the needle.

First up was a perennial favorite despite its seasonal orientation: Joel Cohen’s Sing We Noel with the Boston Camerata [Nonesuch], because it has some drop-dead-beautiful vocals in selections that range from soloists to small choir and period instruments recorded in a rich, warm church ambience. The ambience here is plentiful and should be always in evidence. For example, on side 1, cut 5, when the reader speaks in the left channel, you should be aware of how the reverberation allows his voice to carry across the soundstage; ditto when the soprano sings in the right channel; and when the small choir joins in, it should sound convincingly situated in the space between them. The Koru nailed this.

Other voices, other venues: Doris Day’s “Over the Rainbow” from Hooray for Hollywood. This is a tricky to one get exactly right because Day’s voice is a marvel of lightness and clarity, but there is still a lower register that grounds it. Far too many components, especially with the current taste for etched, exaggerated highs, get the lightness at the expense of a subtle thinness; again, the Koru got it right from the first phrase and projected Day’s voice with pleasing roundedness.

Frank, Nelson, and The Concert Sinatra in MoFi’s latest reissue is arguably the best of the early Reprise albums and worthy of comparison to vintage Capitol. There is fantastic focus and transparency for the voice, bringing it into the room if you play it loud. Meanwhile, those masterly Riddle charts—just listen to the way he wraps an augmented classical orchestra around The Voice, reducing the number of instruments when necessary without ever sounding thin, or swelling for crescendos that never swamp the singer. The end of the show-stopper “My Boy Bill” is an object lesson in how to drop strong brass-led chords into the interstices of a singer’s phrasing so you get the climactic power of a full orchestra without drowning out him and the lyrics. And the way the Koru in combination with the Ortofon Windfeld sets all this out for your delectation, the word “analytical” never crosses your mind. Sinatra and sextet’s Live in Paris, another MoFi reissue, is one of his best live-outing collections.

Though not state-of-the-art sound, it does have that elusive quality of caught-on-the-wing vitality that can sometimes draw you in more persuasively than many a more coiffed studio job can. It certainly did me here, or maybe it was just the beautiful singing. But the recording lets you hear all the flaws (it’s stereo but there’s very little sense of a soundstage as such), and Sinatra sometimes goes off-mike. No matter, magic’s happening in these grooves.

On “Take the A Train” from For Duke, the first peal of Bill Berry’s cornet leaps out of the right speaker with almost shocking immediacy. This is reproduction so vital, explosively dynamic, see- through transparent, and lapel-grabbingly involving that it hardly matters you’d never hear a jazz ensemble sound quite like this live (unless maybe the musicians were actually in your room, and then would be unbearable). The timbres are spot on and the Koru really lets this rip dynamically. What I’m listening for during evaluations is that elusive sense of there being no constriction to the sound. I also want to hear the full vitality of the performers: these guys were charged up and ablaze the two days they cut this album, and there’s no hint of that we-better-get-this-right cautiousness which sometimes disfigures direct-to-disc recordings. Again, the Koru sailed through it all unperturbed.

From a jazz classic to a rock one and Paul Simon’s Graceland. There’s obviously no live-music equivalent to this album, beginning with the synthetic reverb on the opening drum hits. The performers are already in effect so enhanced by the mix itself, which contains so much electric, that I don’t want further enhancement by the equipment. Yet for all the processing, I’ve always found this a very pleasing, easy-on-the-ears album despite how “engineered” it obviously is, perhaps because it never loses a human connection, which is how the Koru reproduced it. With its mix of styles, instruments, genres, continents, and venues, it’s crazy that Simon manages to achieve a unity among these twelve songs. In the a cappella opening to “Diamonds on the soles of Her shoes,” the singers stretch across the soundstage (it actually seems to expand), but on “Homeless,” despite more singers (and, of course, different ones), the perspective is closer and more intimate. so many layers go into an album like this that it can’t possibly be as transparent or as tactile as For Duke, but that slight distance or veil if you will seems to suit a ruminative quality in Simon’s elusive lyrics, even when the music is up-tempo. I’ve listened to this album in whole or in part countless times, but rarely with more attention or greater enjoyment.

I found Plinius’s Hautonga integrated amplifier, which I recently reviewed TAs 229), to be a component distinctly on the Yang side of neutral, not bright as such but with a slight bit of an etched character to it. I hear no evidence of that from the Koru, which leaves me impressed more than anything else with its ease and confidence. There are no readily discernible tonal anomalies up and down the scale, and it renders the highest of highs and the lowest of lows impartially, so far as my ears tell me. Listen to Rhapsodies, Stokowski’s great album of orchestral rhapsodies by Liszt and Enesco, where the doublebasses are powerfully resonant, well defined, yet not “tight” as such, which they never are in actuality. The Bernstein Carmen was every bit as thrilling as it should be, but with a difference that was entirely salutary: Without sacrificing an iota of the almost preternatural excitement of the sound on this remarkable recording, the presentation was much smoother in the highs than I’ve heard from some phonostages, which owed, I believe, at least in part to the proper loading. At the bottom end, where this recording can sound a little wooly, there was also a subtle but welcome impression of increased control and definition.

The Koru also did a superb job keeping the complex textures of Britten’s War Requiem clear as well as reproducing the composer’s spatial effects. As was so often the case, the very enterprising producer John Culshaw created a soundscape for the performance, with a boys’ chorus and an organ soloist separated off to the left and higher than the others, two male soloists toward the front and to the right, Britten’s chamber orchestra and the main chorus behind them and spread across the soundstage, while a soprano, intended to be off by herself and also higher, was placed on the left. Despite the deployment of the various forces in places throughout the hall that have their own microacoustics, as it were, the sense of an integrated space with an enveloping ambience comes through. Height cannot of course be realized in stereo, but the Koru replicated the composer’s spatial directions, which are integral to the music, and Culshaw’s aural landscape very persuasively; brass and tympani in the Die Irae were also quite stunningly registered in the famous Kingsway acoustic.

There was only one anomaly I consistently noted in my listening, which was an ever so slight reduction in apparent depth. At first I thought it was my imagination, but it held across a wide spectrum of recordings. Depending on the characteristics of your transducers, you might not even notice it, but I did, though beyond registering it in my notes, it was small enough that I soon stopped noticing it.

Apart from this, I really don’t have all that much to describe about the sound of this unit because it does its job with such undemonstrative excellence. But while I had the unit I thought I’d run some comparisons with another phonostage which is similarly priced to the Koru and has similar features, notably an adequate range of loading and level options, the tubed Zesto Audio’s Andros ($4500, Issue 222). As with solid-state, so tube electronics have been steadily improving over the years. It’s been a long time since anyone has been able truthfully to tarnish either technology with the brushes of years past: thin, edgy for solid-state; soft, mushy for tubes. And yet, paradoxically, the more they improve and thus move toward each other in sound quality, the more they seem to remain stubbornly different in the way each attempts to render reality. To my ears, anyhow, there is something about the best tube gear that continues to suggest a very subtle Wizard of Oz-like Technicolor prettification of the reproduction and about solid-state an equal pull in the opposite direction—that is, a very subtle desaturation. Or perhaps it’s a matter of texture or fineness of grain. It’s difficult to define but it is there.

I’ve often wished that those who concern themselves with more technical aspects of audio would try to determine what might account for the difference. I personally believe that with electronics of comparable specification, once levels are matched, sonic differences stem fundamentally from anomalies in frequency response and from noise and distortion. But my friends who do measurements tell me they can’t really find anything objective to account for this. Yet one of my technically sophisticated and knowledgeable TAs colleagues, who is much into measurements and gets to listen to a lot of really expensive solid-state gear, once old me that at the end of a hard day he still finds he prefers tubes because they are the equivalent to a long, relaxed “ahhhhh.” Another colleague, equally sophisticated and knowledgeable technically, used to love tubes, but now decisively prefers solid-state because, he says, when it comes to what’s on source material, “I want truth, not euphemism.” For myself, sometimes listening to the best solid- state gear I find myself vaguely hankering for something ever so slightly more flavorful or tasty, and sometimes listening to the best tube gear I find myself vaguely wanting something maybe a little less caloric. (From time to time, availability of equipment permitting, I enjoy using a combination of tubes and solid-state.)

Well, there it is: Nothing to be resolved in a pleasurable afternoon of casual comparisons, let alone in a product review. so I’ll take my leave in a conundrum. One of the best things I can say toward recommending the Andros is that there’s a lot you can say about the sound, little of it not good. One of the best things I can say toward recommending the Koru is that there’s little you can say about the sound and very little of that is not good. You pays your money, you takes your pick . . . but I can’t imagine anyone devoted to vinyl less than happy with either except, perhaps, we audio reviewers, who have to find something to write about.

SPECS & PRICING

Input: RCA unbalanced
Gain: 50dB, 56dB, 60dB, 66dB
Loading options: 47k, 22k, 1k, 470, 220, 100, 47, 22 ohms; input capacitance selectable 100pf or 570pf
Output: RCA unbalanced and XLR balanced
Frequency response: 20Hz—20kHz +/-0.2db referenced to RIAA curve
S/N: -80DB, 5mV input, A-weighted
THD: less than 0.01% at all levels below clipping
Dimensions: 17.75″ x 3.5″ x 15.75″
Weight: 12 lbs.
Price: $3900