The Koetsu Onyx Platinum

Mounting a $10,000 phono cartridge gives you a bit of respect for surgeons: one slip and kaboom! All that craftsmanship down the drain. But the effort is worth it.

Once mounted, moving a smidge here, a smidge there and back a molecule at a time until your vision of setup perfection is reached, and then analog bliss occurs. It certainly does with the $9,995 Koetsu Onyx Platinum phono cartridge.

The entry level Koetsu sound of the Black is very warm and forgiving, almost like a vintage Grado. Moving up the range, each model provides a higher level of depth, dynamics and low-level resolution, never losing the gentleness through the midband that makes these cartridges an object of desire around the world. The Onyx Platinum is nearly the pinnacle of the Koetsu line.

Beginning the audition with a less than perfect record, in this case, the MoFi version of Rickie Lee Jones’ Pirates, instantly captivates. The signature digital edge of this recording is still present, but the inner detail of this previously ignored record is staggering, from beginning to end. Cymbals remain slightly crispy, but the midband is full of warmth, palpability and almost a fourth-dimension of liveliness. If you’re the type of audio enthusiast who wants a “reach out and touch it” experience from your records, the Koetsu delivers the goods. Switching to a better recording, like Shelby Lynne’s classic, Just a Little Lovin’, is otherworldly, and if the rest of your system is up to snuff, this cartridge brings Lynne diabolically close to performing between your speakers. It’s that good, that exciting, that involving.

Aside from the extra-steady hand required with a cartridge of this magnitude, like the other Koetsu cartridges we’ve used, the Onyx Platinum is straightforward to set up. As a relatively low compliance cartridge, a higher mass tonearm is required for this cartridge to deliver the maximum dynamic range. As with past Koetsus, the SME V arms mounted to a few of our reference tables prove a wonderful match as well as the JMW 10.5 arm on the VPI Classic tables.

The test bench

We settle on three major combinations for the Koetsu, all good, yet different. The SME 30, AVID Acutus Reference SP and our highly geeked out Technics SL-1200 – all featuring the SME V tonearm. The SME table proves the weightiest of the three, with the AVID a very close second, yet the Acutus SP proves quicker and more nimble, allowing the Onyx Platinum to sound more open than you might expect. The modded Technics shows surprisingly well, with incredible pace due to its direct drive system, though not possessing the ability to throw as big of a soundstage like the much more expensive AVID and SME tables. SME setup wizards will tell you, as they’ve told me many times, do not use too much damping fluid in the trough, or you will find all that delicacy absent, and you’ll get the “woolly bass” that SME arms are wrongfully noted for. If your SME V has wooly bass, it’s over-damped. Make sure the goo just barely touches the damping paddle and you’re there.

Where the Urushi Blue tracks best at 1.95 grams, the Onyx Platinum settles in at 2.10, offering the best combination of dynamics, HF extension and an incredibly quiet background. The cartridge proves a quick setup in the SME tonearm and after weeks of listening doesn’t feel as if it’s fallen out of alignment like some hypersensitive combinations on the market – another reason I prefer the AVID/SME combination. It’s easy to set up, tolerant of less than perfect setup and does not waver once set up. There may be a more revealing combination, but I love using AVID turntables both for work and pleasure because they are so user friendly, yet offer tremendous performance.

For the more technically inclined, the Onyx Platinum features silver-plated copper windings, with platinum magnets and a solid boron cantilever. Everyone else claims their way is the right way, but Koetsu puts these elements together perfectly. Using the Pass Labs XP-25 phonostage, 100 ohms proves the best loading combination in our reference system.

Those tiny coils only generate .3mv of output, so both the BAT VK-P6SE we recently reviewed (55db of gain) and the phono section of the Audio Research GSPre (56dB) can’t muster enough gain to use the Onyx Platinum successfully. Switching to the Rogers PA-1A with 12AX7 tubes (65dB), the Pass Labs XP-25 (72dB max) and the Simaudio MOON LP 610 (72dB max) gets the job done handily.

More music!

Thirty seconds into the ORG 45 r.p.m. remaster of Duke Ellington’s Jazz Party in Stereo, and you’ll know what the Koetsu magic is all about. Cymbals have seemingly endless decay, and the horns bleat with texture, presence and authority. That being said, Cheap Trick’s In Color sounds pretty damn cool too, with Rick Nielsen’s crunchy guitars having enough bite to feel like one of his Marshall stacks are right here in my listening room.

The wider the range of music in your collection, the more you will appreciate the Onyx Platinum. Comparing it to the other super duper cartridges we’ve lived with long term, it feels somewhere between the spectacular Clearaudio Goldfinger and the Lyra Atlas, with the Goldfinger being even meatier, weightier and more substantial sounding, yet not quite as neutral tonally as the Atlas. All three are amazing, yet if I had all three, the Koetsu would be my daily driver.

Where some cartridges come across as warm, throwing resolution out by the roadside, the Koetsu is more gentle, striking a perfect balance of being ever so slightly forgiving, yet resolving the slightest details at the same time. Yet the presentation offered from this cartridge goes beyond that. If you’ve spent much time with single driver or full range electrostatic speakers, they offer a seamless, cohesive, holistic presentation that no speaker system with multiple drivers can recreate in the same way. What they lack in presenting the last few molecules of dynamic punch or extension is nothing in comparison to the organic recreation of music they offer.

The Koetsu Onyx Platinum is very similar in the sense that the music coming from it unfolds in a way that this unique continuity settles in rather than jostling you into submission. The other high-dollar cartridges are equally compelling, yet in different ways – and much like a Quad 57 speaker, if you love the way it presents music, nothing else will do.

That sums up the performance of the Koetsu Onyx Platinum phono cartridge. If you get the opportunity to hear one and love the way it presents recorded music, it will probably gnaw away at you until you can possess one. While there are plenty of other great phono cartridges costing a lot less money – and you don’t need to spend $10k on a cartridge to enjoy music – if you want this experience, this is what it costs. And if you fall prey to its spell, you will write the check, happily.

Final thoughts: over a year later…

Living with the Onyx Platinum for over a year, I am still just as smitten as I was the day it arrived for review. It’s easy to get caught up in the romance of any product, and living with cartridges at this level can be like courting a mate. Sometimes the initial excitement wears off. Not here.

The Onyx Platinum, now living happily on a Brinkmann Bardo table with RONT power supply continues to deliver the goods. Yet like a bottle of Macallans 60, I don’t serve it to everyone. This is the cartridge I use for serious, personal listening. When the closed sign is on the door and the reviewer hat hangs on the doorknob, the Onyx is my personal choice. And that’s the highest compliment I can give this cartridge. It is pure analog joy. I believe occasional TONE contributor and hifi reviewer extraordinare, Ken Kessler recently arrived at a similar conclusion in HiFi News.

The Koetsu Onyx Platinum Cartridge
MSRP: $9,995

Buy it at:


Turntables                 SME30/SME V tonearm, AVID Acutus Reference SP/SME V tonearm, Technics SL-1200 (heavily modified)/SME V tonearm

Phonostages              Pass Labs XP-25, Rogers PA-1A, Simaudio MOON LP610

Preamplifier              Robert Koda K-10, ARC GSPre, Coffman Labs G1-B

Amplifier                    Pass Labs Xs 300 monoblocks, Audio Research GS150

Speakers                    Quad 2815, GamuT RS5, Dynaudio Evidence Platinum

Power                         IsoTek Super Titan and power cords

Cable                          Cardas Clear, Nordost Frey