Cartridges — Koetsu Onyx Platinum

The Onyx Platinum is a moving-coil phono cartridge from Koetsu, built with a genuine onyx stone body and boron cantilever. Koetsu is a Japanese manufacturer with a legendary reputation among vinyl enthusiasts, hand-building cartridges using exotic body materials and generally commanding some of the highest prices in the category.

Position in line

It sits alongside the Urushi Tsugaru and Azule in Koetsu's cartridge range as related designs using different body materials and finishes. This positioning alongside the Urushi Tsugaru and Azule reflects Koetsu's broader approach of offering essentially similar core cartridge engineering across a wide range of distinct, often exotic body materials, each carrying its own specific price and aesthetic appeal.

Key specs that matter

Output voltage is 0.3 mV, a low figure typical of a moving-coil design needing a high-gain phono stage or step-up transformer to reach usable signal levels. Recommended load is 75-500 ohms. Weight is 12.5 g, a substantial mass for a cartridge, reflecting the genuine onyx stone body material.

Sound and use context

As a cartridge, its contribution is in tracing the groove and converting motion to signal - Koetsu's house sound, generally associated with a rich, warm, deeply engaging tonal character, is legendary within the vinyl enthusiast community and should come through clearly here as it does across the brand's broader range of body-material variants.

Pairing

The 0.3 mV output needs a phono stage with substantial MC gain or a step-up transformer; the 75-500 ohm recommended load range should be checked against a specific phono stage's switchable settings before purchase.

Alternatives

The Urushi Tsugaru and Azule sit alongside this model in Koetsu's cartridge range using different body materials, worth comparing directly with a specialist dealer given how much the specific stone or wood body material affects both price and claimed tonal character across Koetsu's catalogue. Given the considerable investment a cartridge at this level represents, professional installation and careful alignment by an experienced turntable technician are essential rather than optional, since even a well-chosen cartridge can dramatically underperform if mounted incorrectly. Koetsu legendary status within the vinyl enthusiast community means seeking out a specialist dealer with genuine hands-on experience of the brand is worth the research effort.