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From my Japanese friend who is a retired Koetsu engineer and cartridge collector.World famous and Winner of The Absolute Sound's multi-year "Editors' Choice Award".Koetsu Onyx Platinum Diamond MC Moving Coil Cartridge.This cartridge is extremely rare on the market. Handcrafted by Mr. Fumihiko Sugano, owner of Koetsu Co., Ltd., it with an original diamond cantilever. Previously, only one or two pieces were produced each year, so they were often snapped up by Japanese buyers as soon as they were released, making them very difficult to enter the world market.This is a treasure that has been kept for years, like new condition, the sound is the best, beautifully crafted with excellent detail, the speed of sound is faster, and the mid-bass is really tightened and solid, wide dynamic ranges, very sweet and musical, stylus still sharp, cantilever and suspension is also in excellent condition. Used under 200 hours.The Koetsu Onyx Platinum with a diamond cantilever represents a top-tier moving coil cartridge, combining a rare, hand-cut onyx body with advanced platinum-alloy magnets and a diamond cantilever for enhanced detail. It is renowned for merging the classic, warm "Koetsu midrange magic" with superior clarity, faster transient speed, and exceptional pitch certainty on low frequencies.Key findings from reviews of the Onyx Platinum include:Performance:The cartridge is described as delivering incredible texture, color, and musical nuance, with a very "non-digital," organic, and holographic presentation.Diamond Cantilever Impact:The diamond cantilever upgrade notably improves on the standard model by providing higher resolution and a more "real" life-like sound, removing what some describe as a "dirty window pane" effect.Sonic Signature:While maintaining the lush, romantic Koetsu sound, it offers tighter, more defined bass and improved treble extension.Setup: It requires careful matching with a high-quality tonearm and phonoThe Koetsu Onyx Platinum cartridge with Diamond Cantilever is a work of special artistry - a masterpiece both technically and musically. Each is handmade. Each coil is likewise hand wound. It is designed to visually and sonically deliver music as artfully, technically and masterfully as the record artist meant it to be.The first non-wooden bodied Koetsu. The body of the Onyx Platinum is machined from a block of high quality Onyx stone. Each block is carefully selected for natural grain and polished to a very fine finish. The use of Onyx results in the cartridge being one of the heaviest at 12g. The coils and cores are very tightly matched among the production models. The Onyx Platinum is also the only cartridge with tapped mounting holes.The Onyx Platinum is very different from the earlier Onyx series of cartridges which do not have the Platinum alloy magnets. This makes for a world of difference in terms of performance. However, owners of non-Platinum Onyxes need not despair for it is possible to rebuild these units with the same Platinum innards as the Onyx Platinum.Every audiophile music lover knows of the legendary sound of Koetsu phono cartridges from decades past. Those old enough to have experienced Sugano's Koetsus retain the memory of a musical experience unequaled. Few were privileged to own and enjoy a Koetsu. Many of the converted searched out second and third Koetsus, assuring a long, cherished relationship.Now, in analog's Golden Renaissance and through the efforts of Sugano's sons, Koetsu phono cartridges are again available. Though limited in quantity due to their personal, hand built nature, the Sugano family offers a range of models including the Rosewoods, the Urushi, and the ultimate Koetsu, the Onyx Platinum.To fully appreciate Koetsu, we must know Yosiaki Sugano, artist, musician, swordsman, calligrapher, business executive and creator of the world's most renowned phono cartridges. In his youth, choral singing introduced him to western music, He pursued sword making, dueling, calligraphy and painting, emulating his hero, the 17th century Japanese landmark figure, Honami Koetsu. In postwar Japan, Sugano rose to prominence in one of Japan's largest industrial companies, yet continued to pursue his passions, now including hi-fi.In the 1970's, Sugano began to experiment with phono cartridges by substituting his own parts in commercially available models. His keen ear and deductive reasoning, combined with an artist's sensibilities, led to the creation of what would become a legend in audio. Sensing the moment, Sugano named his cartridge after his hero, Koetsu.Sugano's quest led him to enlist universities, specialized industries and master craftspeople to create the special parts to go into his masterpieces. One of the first to use 4 nines copper (99.99% pure), current production uses 6 nines copper (99.9999% pure). Platinum signature models feature silver cladding of the 6 nines copper, a process where a silver sheath is slowly drawn over the copper conductor.Ultra-pure iron square plate formers were sourced for their most predictable magnetic characteristics and lowest oxidation. Pre-aged to the perfect consistency, rubber suspension parts are sourced under license with a rubber damper manufacturer. Special magnetic materials, including Alnico have been featured. Today, samarium-cobalt is used with platinum magnets reserved for the flagship models. Japanese craftsmen carve the rosewood bodies, lacquer coat the Urushi bodies, or cut stone for the onyx Platinum. Styli are specially designed and precision ground for Koetsu.Today, Sugano's sons have revived his art and continue to create musical masterpieces under the watchful eye of the old master. For every music lover, your journey to musical nirvana is incomplete without a Koetsu phono cartridge in your system.Review:"The end result is harmonious and cohesive, and the music unfolds in a way that gives you more time to listen – more time to unravel the individual strands that form part of the whole."Hi-Fi+“… the Koetsu endured in delivering boatloads of color and texture, yet at the same time I’ve never heard a cartridge with greater, clearer pitch certainty on even the lowest bass notes ... All in all, the Koetsu Onyx Platinum communicated color, texture, touch, and musical nuance to an extent and in a combination that I’d never before heard ...”Art DudleyStereophile December 2018Please watch the YouTube videos:Specifications- Body: Onyx stone- Type: Moving coil- Coil wiring: Silver-plated copper- Magnet: Platinum- Stylus type: Proprietary- Cantilever: Diamond- Output voltage: 0.3mV- Frequency response: 20Hz-100kHz- Channel balance @ 1kHz: >0.5dB- Channel separation @ 1kHz: >25dB- Inner impedance: 5 ohms- Recommended impedance: 30 ohms- Weight: 12.5 g- Compliance: 5 x 10-6 cm/dyne @ 100This cartridge comes with Original wood box, Specifications, screws, stylus guard.I have sold a lot of cartridges and got a lot of good feedback, please check them out.And please take a look my other items.Thanks!WayneWayne's Audio
This is a notable cartridge, and the asking price sits well above the typical used market. Against a median of US$3,980 and a 75th percentile of US$4,440, US$12,800 is clearly ambitious, so it needs to be justified by truly exceptional condition, provenance, and any included extras.
Koetsu cartridges are prized for rich tone, texture, and musical flow, especially with a revealing phono stage and a properly matched arm. The upside here is that a clean, original, low-hour example from a respected line can still be a special buy for someone chasing that signature sound, but at this level the buyer should verify stylus condition, hours, retip history, cantilever alignment, and whether the original packaging and paperwork are included.
Independent perspective — not a price guarantee. Always verify condition, accessories and provenance before purchase.
Koetsu traces its origins to Japan in the late 1960s, founded by Yoshiaki Sugano, a remarkable polymath whose background as a boxer, artist, sword maker, and automotive executive fueled his passion for analog audio. Named after the 17th-century artist Honami Koetsu—a distant relative or inspiration—Sugano dissected existing phono cartridges to pioneer high-purity materials like 6N copper coils and rare platinum-iron magnets, driven by his love of Western classical music. He hand-built the first models, such as the Onyx, Rosewood, and Black, retiring from his Toyota/Ford career to perfect their musicality. Sugano passed away in 2002 at age 94, passing the craft to his son Fumihiko, who continued the tradition until his own recent passing, after which the family ceased production.
The brand focuses exclusively on handcrafted moving-coil phono cartridges, blending technical excellence with natural beauty through exotic bodies of stone, rare woods, and Urushi-lacquered finishes. Each cartridge features advanced components like boron cantilevers, line-contact diamond styli, samarium-cobalt magnets, and silver-clad copper windings, all voiced to Sugano's exacting standards on vintage turntables like the Garrard 401. Limited in quantity and available only through select retailers, these sonic masterpieces prioritize vinyl playback refinement over broader categories like amplifiers or speakers.
Koetsu commands reverence in the ultra-high-end market as the pinnacle of cartridge artistry, cult-favored for their poetic tonal delicacy, harmonic resolution, ethereal treble, and authoritative bass—qualities that redefined luxury analog in the 1970s at prices like $800 per unit. Though production has ended, originals remain legendary collector icons, blending generational Japanese craftsmanship with emotional fidelity that divides yet captivates discerning audiophiles.
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