Cartridges — DS Audio Grand Master Extreme

The Grand Master Extreme, also called the Grand Master EX, is an optical phono cartridge from DS Audio of Japan, and it heads the brand's optical cartridge range, above the Grand Master. It is hand-made in Japan with in-house quality control. It was launched on 22 June 2023 at the North West Audio Show in Cheshire, UK, at USD 22,500 or GBP 18,995 for the cartridge alone, and Grand Master owners were offered a 20% upgrade discount.

Key specs that matter

DS Audio uses a 0.22 mm square one-piece diamond cantilever with an integral Micro Ridge tip cut from the same diamond, made by Orbray, formerly Namiki Precision. The body is ultra duralumin, and the cantilever holder is stainless steel. Output exceeds 70 mV, and channel separation is more than 27 dB at 1 kHz. Tracking force is 2.0 to 2.2 g, with 2.1 g recommended. The US distributor gives the weight as 7.7 g.

Engineering and use context

No magnet or coil is involved in producing the signal. Instead, a light from an LED passes a shutter on the cantilever and falls on photodetectors, and the moving shutter changes the amount of light, which the detectors convert into a signal. The Grand Master Extreme uses DS Audio's third-generation optical generator, with independent LEDs and photodetectors for the left and right channels. Because the shutter is very light and there is no magnet or coil to move, the moving mass is low. Cutting the cantilever and stylus from one diamond removes the adhesive joint that normally holds the stylus, so no glue sits between the tip and the cantilever. Diamond is the stiffest cantilever material, so the stylus movement passes to the shutter with little flexing. Because the output follows how far the stylus moves, not how fast, the signal needs a different equalisation curve from a magnetic cartridge. That is why it cannot run into a standard phono stage and needs a DS Audio optical equaliser, which also supplies power to the LEDs. All DS Audio cartridges work with all DS Audio equalisers. The output of more than 70 mV is far above that of magnetic cartridges, so the equaliser needs little gain.

Pairing

The intended partner is the two-chassis Grand Master equaliser with its separate power supply, priced at GBP 42,200. A rigid tonearm that sets the recommended tracking force accurately suits the diamond cantilever.

Alternatives

The DS Audio Grand Master is the optical cartridge one step below, with a bonded diamond cantilever.